[PATCH v4 00/13] io_uring: buffer registration enhancements

[PATCH v4 00/13] io_uring: buffer registration enhancements

[Bijan Mottahedeh]

v4:

- address v3 comments (TBD REGISTER_BUFFERS)
- rebase

v3:

- batch file->rsrc renames into a signle patch when possible
- fix other review changes from v2
- fix checkpatch warnings

v2:

- drop readv/writev with fixed buffers patch
- handle ref_nodes both both files/buffers with a single ref_list
- make file/buffer handling more unified

This patchset implements a set of enhancements to buffer registration
consistent with existing file registration functionality:

- buffer registration updates		IORING_REGISTER_BUFFERS_UPDATE
					IORING_OP_BUFFERS_UPDATE

- buffer registration sharing		IORING_SETUP_SHARE_BUF
					IORING_SETUP_ATTACH_BUF

I have kept the original patchset unchanged for the most part to
facilitate reviewing and so this set adds a number of additional patches
mostly making file/buffer handling more unified.

Patch 1-2 modularize existing buffer registration code.

Patch 3-7 generalize fixed_file functionality to fixed_rsrc.

Patch 8 applies fixed_rsrc functionality for fixed buffers support.

Patch 9-10 generalize files_update functionality to rsrc_update.

Patch 11 implements buffer registration update, and introduces
IORING_REGISTER_BUFFERS_UPDATE and IORING_OP_BUFFERS_UPDATE, consistent
with file registration update.

Patch 12 generalizes fixed resource allocation 

Patch 13 implements buffer sharing among multiple rings; it works as follows:

- A new ring, A,  is setup. Since no buffers have been registered, the
  registered buffer state is an empty set, Z. That's different from the
  NULL state in current implementation.

- Ring B is setup, attaching to Ring A. It's also attaching to it's
  buffer registrations, now we have two references to the same empty
  set, Z.

- Ring A registers buffers into set Z, which is no longer empty.

- Ring B sees this immediately, since it's already sharing that set.

Testing

I have used liburing file-{register,update} tests as models for
buffer-{register,update,share}, tests and they run ok.

TBD

- I tried to use a single opcode for files/buffers but ran into an
issue since work_flags is different for files/buffers.  This should
be ok for the most part since req->work.flags is ultimately examined;
however, there are place where io_op_defs[opcode].work_flags is examined
directly, and I wasn't sure what would the best way to handle that.

- Need to still address Pavel's comments about deadlocks. I figure
to send out the set anyway since this is a last patch and may even be
handled separately.

Bijan Mottahedeh (13):
  io_uring: modularize io_sqe_buffer_register
  io_uring: modularize io_sqe_buffers_register
  io_uring: rename file related variables to rsrc
  io_uring: generalize io_queue_rsrc_removal
  io_uring: separate ref_list from fixed_rsrc_data
  io_uring: split alloc_fixed_file_ref_node
  io_uring: add rsrc_ref locking routines
  io_uring: implement fixed buffers registration similar to fixed files
  io_uring: create common fixed_rsrc_ref_node handling routines
  io_uring: generalize files_update functionlity to rsrc_update
  io_uring: support buffer registration updates
  io_uring: create common fixed_rsrc_data allocation routines
  io_uring: support buffer registration sharing

 fs/io_uring.c                 | 1002 +++++++++++++++++++++++++++++------------
 include/uapi/linux/io_uring.h |   13 +-
 2 files changed, 733 insertions(+), 282 deletions(-)

-- 
1.8.3.1

[PATCH v4 01/13] io_uring: modularize io_sqe_buffer_register

[Bijan Mottahedeh]

Split io_sqe_buffer_register into two routines:

- io_sqe_buffer_register() registers a single buffer
- io_sqe_buffers_register iterates over all user specified buffers

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c | 210 ++++++++++++++++++++++++++++++----------------------------
 1 file changed, 107 insertions(+), 103 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 27a8c22..2708409 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8281,7 +8281,7 @@ static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
 	return pages;
 }
 
-static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
+static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
 {
 	int i, j;
 
@@ -8399,14 +8399,103 @@ static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
 	return ret;
 }
 
-static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
-				  unsigned nr_args)
+static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
+				  struct io_mapped_ubuf *imu,
+				  struct page **last_hpage)
 {
 	struct vm_area_struct **vmas = NULL;
 	struct page **pages = NULL;
+	unsigned long off, start, end, ubuf;
+	size_t size;
+	int ret, pret, nr_pages, i;
+
+	ubuf = (unsigned long) iov->iov_base;
+	end = (ubuf + iov->iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	start = ubuf >> PAGE_SHIFT;
+	nr_pages = end - start;
+
+	ret = -ENOMEM;
+
+	pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
+	if (!pages)
+		goto done;
+
+	vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *),
+			      GFP_KERNEL);
+	if (!vmas)
+		goto done;
+
+	imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec),
+				   GFP_KERNEL);
+	if (!imu->bvec)
+		goto done;
+
+	ret = 0;
+	mmap_read_lock(current->mm);
+	pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
+			      pages, vmas);
+	if (pret == nr_pages) {
+		/* don't support file backed memory */
+		for (i = 0; i < nr_pages; i++) {
+			struct vm_area_struct *vma = vmas[i];
+
+			if (vma->vm_file &&
+			    !is_file_hugepages(vma->vm_file)) {
+				ret = -EOPNOTSUPP;
+				break;
+			}
+		}
+	} else {
+		ret = pret < 0 ? pret : -EFAULT;
+	}
+	mmap_read_unlock(current->mm);
+	if (ret) {
+		/*
+		 * if we did partial map, or found file backed vmas,
+		 * release any pages we did get
+		 */
+		if (pret > 0)
+			unpin_user_pages(pages, pret);
+		kvfree(imu->bvec);
+		goto done;
+	}
+
+	ret = io_buffer_account_pin(ctx, pages, pret, imu, last_hpage);
+	if (ret) {
+		unpin_user_pages(pages, pret);
+		kvfree(imu->bvec);
+		goto done;
+	}
+
+	off = ubuf & ~PAGE_MASK;
+	size = iov->iov_len;
+	for (i = 0; i < nr_pages; i++) {
+		size_t vec_len;
+
+		vec_len = min_t(size_t, size, PAGE_SIZE - off);
+		imu->bvec[i].bv_page = pages[i];
+		imu->bvec[i].bv_len = vec_len;
+		imu->bvec[i].bv_offset = off;
+		off = 0;
+		size -= vec_len;
+	}
+	/* store original address for later verification */
+	imu->ubuf = ubuf;
+	imu->len = iov->iov_len;
+	imu->nr_bvecs = nr_pages;
+	ret = 0;
+done:
+	kvfree(pages);
+	kvfree(vmas);
+	return ret;
+}
+
+static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
+				   unsigned int nr_args)
+{
+	int i, ret;
+	struct iovec iov;
 	struct page *last_hpage = NULL;
-	int i, j, got_pages = 0;
-	int ret = -EINVAL;
 
 	if (ctx->user_bufs)
 		return -EBUSY;
@@ -8420,14 +8509,10 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
 
 	for (i = 0; i < nr_args; i++) {
 		struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
-		unsigned long off, start, end, ubuf;
-		int pret, nr_pages;
-		struct iovec iov;
-		size_t size;
 
 		ret = io_copy_iov(ctx, &iov, arg, i);
 		if (ret)
-			goto err;
+			break;
 
 		/*
 		 * Don't impose further limits on the size and buffer
@@ -8436,103 +8521,22 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
 		 */
 		ret = -EFAULT;
 		if (!iov.iov_base || !iov.iov_len)
-			goto err;
+			break;
 
 		/* arbitrary limit, but we need something */
 		if (iov.iov_len > SZ_1G)
-			goto err;
-
-		ubuf = (unsigned long) iov.iov_base;
-		end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
-		start = ubuf >> PAGE_SHIFT;
-		nr_pages = end - start;
-
-		ret = 0;
-		if (!pages || nr_pages > got_pages) {
-			kvfree(vmas);
-			kvfree(pages);
-			pages = kvmalloc_array(nr_pages, sizeof(struct page *),
-						GFP_KERNEL);
-			vmas = kvmalloc_array(nr_pages,
-					sizeof(struct vm_area_struct *),
-					GFP_KERNEL);
-			if (!pages || !vmas) {
-				ret = -ENOMEM;
-				goto err;
-			}
-			got_pages = nr_pages;
-		}
-
-		imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec),
-						GFP_KERNEL);
-		ret = -ENOMEM;
-		if (!imu->bvec)
-			goto err;
-
-		ret = 0;
-		mmap_read_lock(current->mm);
-		pret = pin_user_pages(ubuf, nr_pages,
-				      FOLL_WRITE | FOLL_LONGTERM,
-				      pages, vmas);
-		if (pret == nr_pages) {
-			/* don't support file backed memory */
-			for (j = 0; j < nr_pages; j++) {
-				struct vm_area_struct *vma = vmas[j];
-
-				if (vma->vm_file &&
-				    !is_file_hugepages(vma->vm_file)) {
-					ret = -EOPNOTSUPP;
-					break;
-				}
-			}
-		} else {
-			ret = pret < 0 ? pret : -EFAULT;
-		}
-		mmap_read_unlock(current->mm);
-		if (ret) {
-			/*
-			 * if we did partial map, or found file backed vmas,
-			 * release any pages we did get
-			 */
-			if (pret > 0)
-				unpin_user_pages(pages, pret);
-			kvfree(imu->bvec);
-			goto err;
-		}
-
-		ret = io_buffer_account_pin(ctx, pages, pret, imu, &last_hpage);
-		if (ret) {
-			unpin_user_pages(pages, pret);
-			kvfree(imu->bvec);
-			goto err;
-		}
+			break;
 
-		off = ubuf & ~PAGE_MASK;
-		size = iov.iov_len;
-		for (j = 0; j < nr_pages; j++) {
-			size_t vec_len;
-
-			vec_len = min_t(size_t, size, PAGE_SIZE - off);
-			imu->bvec[j].bv_page = pages[j];
-			imu->bvec[j].bv_len = vec_len;
-			imu->bvec[j].bv_offset = off;
-			off = 0;
-			size -= vec_len;
-		}
-		/* store original address for later verification */
-		imu->ubuf = ubuf;
-		imu->len = iov.iov_len;
-		imu->nr_bvecs = nr_pages;
+		ret = io_sqe_buffer_register(ctx, &iov, imu, &last_hpage);
+		if (ret)
+			break;
 
 		ctx->nr_user_bufs++;
 	}
-	kvfree(pages);
-	kvfree(vmas);
-	return 0;
-err:
-	kvfree(pages);
-	kvfree(vmas);
-	io_sqe_buffer_unregister(ctx);
+
+	if (ret)
+		io_sqe_buffers_unregister(ctx);
+
 	return ret;
 }
 
@@ -8586,7 +8590,7 @@ static void io_destroy_buffers(struct io_ring_ctx *ctx)
 static void io_ring_ctx_free(struct io_ring_ctx *ctx)
 {
 	io_finish_async(ctx);
-	io_sqe_buffer_unregister(ctx);
+	io_sqe_buffers_unregister(ctx);
 
 	if (ctx->sqo_task) {
 		put_task_struct(ctx->sqo_task);
@@ -9913,13 +9917,13 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
 
 	switch (opcode) {
 	case IORING_REGISTER_BUFFERS:
-		ret = io_sqe_buffer_register(ctx, arg, nr_args);
+		ret = io_sqe_buffers_register(ctx, arg, nr_args);
 		break;
 	case IORING_UNREGISTER_BUFFERS:
 		ret = -EINVAL;
 		if (arg || nr_args)
 			break;
-		ret = io_sqe_buffer_unregister(ctx);
+		ret = io_sqe_buffers_unregister(ctx);
 		break;
 	case IORING_REGISTER_FILES:
 		ret = io_sqe_files_register(ctx, arg, nr_args);
-- 
1.8.3.1

[PATCH v4 02/13] io_uring: modularize io_sqe_buffers_register

[Bijan Mottahedeh]

Move allocation of buffer management structures, and validation of
buffers into separate routines.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c | 51 ++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 34 insertions(+), 17 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2708409..ed90dbe 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8490,13 +8490,8 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
 	return ret;
 }
 
-static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
-				   unsigned int nr_args)
+static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
 {
-	int i, ret;
-	struct iovec iov;
-	struct page *last_hpage = NULL;
-
 	if (ctx->user_bufs)
 		return -EBUSY;
 	if (!nr_args || nr_args > UIO_MAXIOV)
@@ -8507,6 +8502,37 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 	if (!ctx->user_bufs)
 		return -ENOMEM;
 
+	return 0;
+}
+
+static int io_buffer_validate(struct iovec *iov)
+{
+	/*
+	 * Don't impose further limits on the size and buffer
+	 * constraints here, we'll -EINVAL later when IO is
+	 * submitted if they are wrong.
+	 */
+	if (!iov->iov_base || !iov->iov_len)
+		return -EFAULT;
+
+	/* arbitrary limit, but we need something */
+	if (iov->iov_len > SZ_1G)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
+				   unsigned int nr_args)
+{
+	int i, ret;
+	struct iovec iov;
+	struct page *last_hpage = NULL;
+
+	ret = io_buffers_map_alloc(ctx, nr_args);
+	if (ret)
+		return ret;
+
 	for (i = 0; i < nr_args; i++) {
 		struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
 
@@ -8514,17 +8540,8 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 		if (ret)
 			break;
 
-		/*
-		 * Don't impose further limits on the size and buffer
-		 * constraints here, we'll -EINVAL later when IO is
-		 * submitted if they are wrong.
-		 */
-		ret = -EFAULT;
-		if (!iov.iov_base || !iov.iov_len)
-			break;
-
-		/* arbitrary limit, but we need something */
-		if (iov.iov_len > SZ_1G)
+		ret = io_buffer_validate(&iov);
+		if (ret)
 			break;
 
 		ret = io_sqe_buffer_register(ctx, &iov, imu, &last_hpage);
-- 
1.8.3.1

[PATCH v4 03/13] io_uring: rename file related variables to rsrc

[Bijan Mottahedeh]

This is a prep rename patch for subsequent patches to generalize file
registration.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c                 | 226 ++++++++++++++++++++++--------------------
 include/uapi/linux/io_uring.h |   3 +-
 2 files changed, 118 insertions(+), 111 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ed90dbe..2c5d8c3 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -195,24 +195,29 @@ struct io_mapped_ubuf {
 	unsigned long	acct_pages;
 };
 
-struct fixed_file_table {
+struct io_rsrc_put {
+	struct list_head list;
+	struct file *file;
+};
+
+struct fixed_rsrc_table {
 	struct file		**files;
 };
 
-struct fixed_file_ref_node {
+struct fixed_rsrc_ref_node {
 	struct percpu_ref		refs;
 	struct list_head		node;
-	struct list_head		file_list;
-	struct fixed_file_data		*file_data;
+	struct list_head		rsrc_list;
+	struct fixed_rsrc_data		*rsrc_data;
 	struct llist_node		llist;
 	bool				done;
 };
 
-struct fixed_file_data {
-	struct fixed_file_table		*table;
+struct fixed_rsrc_data {
+	struct fixed_rsrc_table		*table;
 	struct io_ring_ctx		*ctx;
 
-	struct fixed_file_ref_node	*node;
+	struct fixed_rsrc_ref_node	*node;
 	struct percpu_ref		refs;
 	struct completion		done;
 	struct list_head		ref_list;
@@ -318,7 +323,7 @@ struct io_ring_ctx {
 	 * readers must ensure that ->refs is alive as long as the file* is
 	 * used. Only updated through io_uring_register(2).
 	 */
-	struct fixed_file_data	*file_data;
+	struct fixed_rsrc_data	*file_data;
 	unsigned		nr_user_files;
 
 	/* if used, fixed mapped user buffers */
@@ -382,8 +387,8 @@ struct io_ring_ctx {
 		struct list_head	inflight_list;
 	} ____cacheline_aligned_in_smp;
 
-	struct delayed_work		file_put_work;
-	struct llist_head		file_put_llist;
+	struct delayed_work		rsrc_put_work;
+	struct llist_head		rsrc_put_llist;
 
 	struct work_struct		exit_work;
 	struct io_restriction		restrictions;
@@ -493,7 +498,7 @@ struct io_open {
 	unsigned long			nofile;
 };
 
-struct io_files_update {
+struct io_rsrc_update {
 	struct file			*file;
 	u64				arg;
 	u32				nr_args;
@@ -687,7 +692,7 @@ struct io_kiocb {
 		struct io_sr_msg	sr_msg;
 		struct io_open		open;
 		struct io_close		close;
-		struct io_files_update	files_update;
+		struct io_rsrc_update	rsrc_update;
 		struct io_fadvise	fadvise;
 		struct io_madvise	madvise;
 		struct io_epoll		epoll;
@@ -717,7 +722,7 @@ struct io_kiocb {
 	u64				user_data;
 
 	struct io_kiocb			*link;
-	struct percpu_ref		*fixed_file_refs;
+	struct percpu_ref		*fixed_rsrc_refs;
 
 	/*
 	 * 1. used with ctx->iopoll_list with reads/writes
@@ -995,8 +1000,8 @@ enum io_mem_account {
 static void __io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
 					    struct task_struct *task);
 
-static void destroy_fixed_file_ref_node(struct fixed_file_ref_node *ref_node);
-static struct fixed_file_ref_node *alloc_fixed_file_ref_node(
+static void destroy_fixed_rsrc_ref_node(struct fixed_rsrc_ref_node *ref_node);
+static struct fixed_rsrc_ref_node *alloc_fixed_file_ref_node(
 			struct io_ring_ctx *ctx);
 
 static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
@@ -1009,13 +1014,13 @@ static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
 static void __io_queue_linked_timeout(struct io_kiocb *req);
 static void io_queue_linked_timeout(struct io_kiocb *req);
 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
-				 struct io_uring_files_update *ip,
+				 struct io_uring_rsrc_update *ip,
 				 unsigned nr_args);
 static void __io_clean_op(struct io_kiocb *req);
 static struct file *io_file_get(struct io_submit_state *state,
 				struct io_kiocb *req, int fd, bool fixed);
 static void __io_queue_sqe(struct io_kiocb *req, struct io_comp_state *cs);
-static void io_file_put_work(struct work_struct *work);
+static void io_rsrc_put_work(struct work_struct *work);
 
 static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
 			       struct iovec **iovec, struct iov_iter *iter,
@@ -1055,9 +1060,9 @@ static inline void io_set_resource_node(struct io_kiocb *req)
 {
 	struct io_ring_ctx *ctx = req->ctx;
 
-	if (!req->fixed_file_refs) {
-		req->fixed_file_refs = &ctx->file_data->node->refs;
-		percpu_ref_get(req->fixed_file_refs);
+	if (!req->fixed_rsrc_refs) {
+		req->fixed_rsrc_refs = &ctx->file_data->node->refs;
+		percpu_ref_get(req->fixed_rsrc_refs);
 	}
 }
 
@@ -1316,8 +1321,8 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
 	INIT_LIST_HEAD(&ctx->timeout_list);
 	spin_lock_init(&ctx->inflight_lock);
 	INIT_LIST_HEAD(&ctx->inflight_list);
-	INIT_DELAYED_WORK(&ctx->file_put_work, io_file_put_work);
-	init_llist_head(&ctx->file_put_llist);
+	INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
+	init_llist_head(&ctx->rsrc_put_llist);
 	return ctx;
 err:
 	if (ctx->fallback_req)
@@ -1957,8 +1962,8 @@ static void io_dismantle_req(struct io_kiocb *req)
 		kfree(req->async_data);
 	if (req->file)
 		io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));
-	if (req->fixed_file_refs)
-		percpu_ref_put(req->fixed_file_refs);
+	if (req->fixed_rsrc_refs)
+		percpu_ref_put(req->fixed_rsrc_refs);
 	io_req_clean_work(req);
 }
 
@@ -5915,7 +5920,7 @@ static int io_async_cancel(struct io_kiocb *req)
 	return 0;
 }
 
-static int io_files_update_prep(struct io_kiocb *req,
+static int io_rsrc_update_prep(struct io_kiocb *req,
 				const struct io_uring_sqe *sqe)
 {
 	if (unlikely(req->ctx->flags & IORING_SETUP_SQPOLL))
@@ -5925,11 +5930,11 @@ static int io_files_update_prep(struct io_kiocb *req,
 	if (sqe->ioprio || sqe->rw_flags)
 		return -EINVAL;
 
-	req->files_update.offset = READ_ONCE(sqe->off);
-	req->files_update.nr_args = READ_ONCE(sqe->len);
-	if (!req->files_update.nr_args)
+	req->rsrc_update.offset = READ_ONCE(sqe->off);
+	req->rsrc_update.nr_args = READ_ONCE(sqe->len);
+	if (!req->rsrc_update.nr_args)
 		return -EINVAL;
-	req->files_update.arg = READ_ONCE(sqe->addr);
+	req->rsrc_update.arg = READ_ONCE(sqe->addr);
 	return 0;
 }
 
@@ -5937,17 +5942,17 @@ static int io_files_update(struct io_kiocb *req, bool force_nonblock,
 			   struct io_comp_state *cs)
 {
 	struct io_ring_ctx *ctx = req->ctx;
-	struct io_uring_files_update up;
+	struct io_uring_rsrc_update up;
 	int ret;
 
 	if (force_nonblock)
 		return -EAGAIN;
 
-	up.offset = req->files_update.offset;
-	up.fds = req->files_update.arg;
+	up.offset = req->rsrc_update.offset;
+	up.fds = req->rsrc_update.arg;
 
 	mutex_lock(&ctx->uring_lock);
-	ret = __io_sqe_files_update(ctx, &up, req->files_update.nr_args);
+	ret = __io_sqe_files_update(ctx, &up, req->rsrc_update.nr_args);
 	mutex_unlock(&ctx->uring_lock);
 
 	if (ret < 0)
@@ -6002,7 +6007,7 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	case IORING_OP_CLOSE:
 		return io_close_prep(req, sqe);
 	case IORING_OP_FILES_UPDATE:
-		return io_files_update_prep(req, sqe);
+		return io_rsrc_update_prep(req, sqe);
 	case IORING_OP_STATX:
 		return io_statx_prep(req, sqe);
 	case IORING_OP_FADVISE:
@@ -6372,7 +6377,7 @@ static struct io_wq_work *io_wq_submit_work(struct io_wq_work *work)
 static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,
 					      int index)
 {
-	struct fixed_file_table *table;
+	struct fixed_rsrc_table *table;
 
 	table = &ctx->file_data->table[index >> IORING_FILE_TABLE_SHIFT];
 	return table->files[index & IORING_FILE_TABLE_MASK];
@@ -6758,7 +6763,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
 	req->ctx = ctx;
 	req->flags = 0;
 	req->link = NULL;
-	req->fixed_file_refs = NULL;
+	req->fixed_rsrc_refs = NULL;
 	/* one is dropped after submission, the other at completion */
 	refcount_set(&req->refs, 2);
 	req->task = current;
@@ -7239,28 +7244,28 @@ static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
 #endif
 }
 
-static void io_file_ref_kill(struct percpu_ref *ref)
+static void io_rsrc_ref_kill(struct percpu_ref *ref)
 {
-	struct fixed_file_data *data;
+	struct fixed_rsrc_data *data;
 
-	data = container_of(ref, struct fixed_file_data, refs);
+	data = container_of(ref, struct fixed_rsrc_data, refs);
 	complete(&data->done);
 }
 
-static void io_sqe_files_set_node(struct fixed_file_data *file_data,
-				  struct fixed_file_ref_node *ref_node)
+static void io_sqe_rsrc_set_node(struct fixed_rsrc_data *rsrc_data,
+				 struct fixed_rsrc_ref_node *ref_node)
 {
-	spin_lock_bh(&file_data->lock);
-	file_data->node = ref_node;
-	list_add_tail(&ref_node->node, &file_data->ref_list);
-	spin_unlock_bh(&file_data->lock);
-	percpu_ref_get(&file_data->refs);
+	spin_lock_bh(&rsrc_data->lock);
+	rsrc_data->node = ref_node;
+	list_add_tail(&ref_node->node, &rsrc_data->ref_list);
+	spin_unlock_bh(&rsrc_data->lock);
+	percpu_ref_get(&rsrc_data->refs);
 }
 
 static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 {
-	struct fixed_file_data *data = ctx->file_data;
-	struct fixed_file_ref_node *backup_node, *ref_node = NULL;
+	struct fixed_rsrc_data *data = ctx->file_data;
+	struct fixed_rsrc_ref_node *backup_node, *ref_node = NULL;
 	unsigned nr_tables, i;
 	int ret;
 
@@ -7279,7 +7284,7 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 	percpu_ref_kill(&data->refs);
 
 	/* wait for all refs nodes to complete */
-	flush_delayed_work(&ctx->file_put_work);
+	flush_delayed_work(&ctx->rsrc_put_work);
 	do {
 		ret = wait_for_completion_interruptible(&data->done);
 		if (!ret)
@@ -7288,7 +7293,7 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 		if (ret < 0) {
 			percpu_ref_resurrect(&data->refs);
 			reinit_completion(&data->done);
-			io_sqe_files_set_node(data, backup_node);
+			io_sqe_rsrc_set_node(data, backup_node);
 			return ret;
 		}
 	} while (1);
@@ -7302,7 +7307,7 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 	kfree(data);
 	ctx->file_data = NULL;
 	ctx->nr_user_files = 0;
-	destroy_fixed_file_ref_node(backup_node);
+	destroy_fixed_rsrc_ref_node(backup_node);
 	return 0;
 }
 
@@ -7525,13 +7530,13 @@ static int io_sqe_files_scm(struct io_ring_ctx *ctx)
 }
 #endif
 
-static int io_sqe_alloc_file_tables(struct fixed_file_data *file_data,
+static int io_sqe_alloc_file_tables(struct fixed_rsrc_data *file_data,
 				    unsigned nr_tables, unsigned nr_files)
 {
 	int i;
 
 	for (i = 0; i < nr_tables; i++) {
-		struct fixed_file_table *table = &file_data->table[i];
+		struct fixed_rsrc_table *table = &file_data->table[i];
 		unsigned this_files;
 
 		this_files = min(nr_files, IORING_MAX_FILES_TABLE);
@@ -7546,7 +7551,7 @@ static int io_sqe_alloc_file_tables(struct fixed_file_data *file_data,
 		return 0;
 
 	for (i = 0; i < nr_tables; i++) {
-		struct fixed_file_table *table = &file_data->table[i];
+		struct fixed_rsrc_table *table = &file_data->table[i];
 		kfree(table->files);
 	}
 	return 1;
@@ -7614,56 +7619,51 @@ static void io_ring_file_put(struct io_ring_ctx *ctx, struct file *file)
 #endif
 }
 
-struct io_file_put {
-	struct list_head list;
-	struct file *file;
-};
-
-static void __io_file_put_work(struct fixed_file_ref_node *ref_node)
+static void __io_rsrc_put_work(struct fixed_rsrc_ref_node *ref_node)
 {
-	struct fixed_file_data *file_data = ref_node->file_data;
-	struct io_ring_ctx *ctx = file_data->ctx;
-	struct io_file_put *pfile, *tmp;
+	struct fixed_rsrc_data *rsrc_data = ref_node->rsrc_data;
+	struct io_ring_ctx *ctx = rsrc_data->ctx;
+	struct io_rsrc_put *prsrc, *tmp;
 
-	list_for_each_entry_safe(pfile, tmp, &ref_node->file_list, list) {
-		list_del(&pfile->list);
-		io_ring_file_put(ctx, pfile->file);
-		kfree(pfile);
+	list_for_each_entry_safe(prsrc, tmp, &ref_node->rsrc_list, list) {
+		list_del(&prsrc->list);
+		io_ring_file_put(ctx, prsrc->file);
+		kfree(prsrc);
 	}
 
 	percpu_ref_exit(&ref_node->refs);
 	kfree(ref_node);
-	percpu_ref_put(&file_data->refs);
+	percpu_ref_put(&rsrc_data->refs);
 }
 
-static void io_file_put_work(struct work_struct *work)
+static void io_rsrc_put_work(struct work_struct *work)
 {
 	struct io_ring_ctx *ctx;
 	struct llist_node *node;
 
-	ctx = container_of(work, struct io_ring_ctx, file_put_work.work);
-	node = llist_del_all(&ctx->file_put_llist);
+	ctx = container_of(work, struct io_ring_ctx, rsrc_put_work.work);
+	node = llist_del_all(&ctx->rsrc_put_llist);
 
 	while (node) {
-		struct fixed_file_ref_node *ref_node;
+		struct fixed_rsrc_ref_node *ref_node;
 		struct llist_node *next = node->next;
 
-		ref_node = llist_entry(node, struct fixed_file_ref_node, llist);
-		__io_file_put_work(ref_node);
+		ref_node = llist_entry(node, struct fixed_rsrc_ref_node, llist);
+		__io_rsrc_put_work(ref_node);
 		node = next;
 	}
 }
 
-static void io_file_data_ref_zero(struct percpu_ref *ref)
+static void io_rsrc_data_ref_zero(struct percpu_ref *ref)
 {
-	struct fixed_file_ref_node *ref_node;
-	struct fixed_file_data *data;
+	struct fixed_rsrc_ref_node *ref_node;
+	struct fixed_rsrc_data *data;
 	struct io_ring_ctx *ctx;
 	bool first_add = false;
 	int delay = HZ;
 
-	ref_node = container_of(ref, struct fixed_file_ref_node, refs);
-	data = ref_node->file_data;
+	ref_node = container_of(ref, struct fixed_rsrc_ref_node, refs);
+	data = ref_node->rsrc_data;
 	ctx = data->ctx;
 
 	spin_lock_bh(&data->lock);
@@ -7671,12 +7671,12 @@ static void io_file_data_ref_zero(struct percpu_ref *ref)
 
 	while (!list_empty(&data->ref_list)) {
 		ref_node = list_first_entry(&data->ref_list,
-					struct fixed_file_ref_node, node);
+					struct fixed_rsrc_ref_node, node);
 		/* recycle ref nodes in order */
 		if (!ref_node->done)
 			break;
 		list_del(&ref_node->node);
-		first_add |= llist_add(&ref_node->llist, &ctx->file_put_llist);
+		first_add |= llist_add(&ref_node->llist, &ctx->rsrc_put_llist);
 	}
 	spin_unlock_bh(&data->lock);
 
@@ -7684,33 +7684,33 @@ static void io_file_data_ref_zero(struct percpu_ref *ref)
 		delay = 0;
 
 	if (!delay)
-		mod_delayed_work(system_wq, &ctx->file_put_work, 0);
+		mod_delayed_work(system_wq, &ctx->rsrc_put_work, 0);
 	else if (first_add)
-		queue_delayed_work(system_wq, &ctx->file_put_work, delay);
+		queue_delayed_work(system_wq, &ctx->rsrc_put_work, delay);
 }
 
-static struct fixed_file_ref_node *alloc_fixed_file_ref_node(
+static struct fixed_rsrc_ref_node *alloc_fixed_file_ref_node(
 			struct io_ring_ctx *ctx)
 {
-	struct fixed_file_ref_node *ref_node;
+	struct fixed_rsrc_ref_node *ref_node;
 
 	ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
 	if (!ref_node)
 		return NULL;
 
-	if (percpu_ref_init(&ref_node->refs, io_file_data_ref_zero,
+	if (percpu_ref_init(&ref_node->refs, io_rsrc_data_ref_zero,
 			    0, GFP_KERNEL)) {
 		kfree(ref_node);
 		return NULL;
 	}
 	INIT_LIST_HEAD(&ref_node->node);
-	INIT_LIST_HEAD(&ref_node->file_list);
-	ref_node->file_data = ctx->file_data;
+	INIT_LIST_HEAD(&ref_node->rsrc_list);
+	ref_node->rsrc_data = ctx->file_data;
 	ref_node->done = false;
 	return ref_node;
 }
 
-static void destroy_fixed_file_ref_node(struct fixed_file_ref_node *ref_node)
+static void destroy_fixed_rsrc_ref_node(struct fixed_rsrc_ref_node *ref_node)
 {
 	percpu_ref_exit(&ref_node->refs);
 	kfree(ref_node);
@@ -7723,8 +7723,8 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 	unsigned nr_tables, i;
 	struct file *file;
 	int fd, ret = -ENOMEM;
-	struct fixed_file_ref_node *ref_node;
-	struct fixed_file_data *file_data;
+	struct fixed_rsrc_ref_node *ref_node;
+	struct fixed_rsrc_data *file_data;
 
 	if (ctx->file_data)
 		return -EBUSY;
@@ -7747,7 +7747,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 	if (!file_data->table)
 		goto out_free;
 
-	if (percpu_ref_init(&file_data->refs, io_file_ref_kill,
+	if (percpu_ref_init(&file_data->refs, io_rsrc_ref_kill,
 				PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
 		goto out_free;
 
@@ -7756,7 +7756,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 	ctx->file_data = file_data;
 
 	for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
-		struct fixed_file_table *table;
+		struct fixed_rsrc_table *table;
 		unsigned index;
 
 		if (copy_from_user(&fd, &fds[i], sizeof(fd))) {
@@ -7800,7 +7800,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 		return -ENOMEM;
 	}
 
-	io_sqe_files_set_node(file_data, ref_node);
+	io_sqe_rsrc_set_node(file_data, ref_node);
 	return ret;
 out_fput:
 	for (i = 0; i < ctx->nr_user_files; i++) {
@@ -7863,28 +7863,34 @@ static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
 #endif
 }
 
-static int io_queue_file_removal(struct fixed_file_data *data,
-				 struct file *file)
+static int io_queue_rsrc_removal(struct fixed_rsrc_data *data,
+				 struct file *rsrc)
 {
-	struct io_file_put *pfile;
-	struct fixed_file_ref_node *ref_node = data->node;
+	struct io_rsrc_put *prsrc;
+	struct fixed_rsrc_ref_node *ref_node = data->node;
 
-	pfile = kzalloc(sizeof(*pfile), GFP_KERNEL);
-	if (!pfile)
+	prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL);
+	if (!prsrc)
 		return -ENOMEM;
 
-	pfile->file = file;
-	list_add(&pfile->list, &ref_node->file_list);
+	prsrc->file = rsrc;
+	list_add(&prsrc->list, &ref_node->rsrc_list);
 
 	return 0;
 }
 
+static inline int io_queue_file_removal(struct fixed_rsrc_data *data,
+					struct file *file)
+{
+	return io_queue_rsrc_removal(data, file);
+}
+
 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
-				 struct io_uring_files_update *up,
+				 struct io_uring_rsrc_update *up,
 				 unsigned nr_args)
 {
-	struct fixed_file_data *data = ctx->file_data;
-	struct fixed_file_ref_node *ref_node;
+	struct fixed_rsrc_data *data = ctx->file_data;
+	struct fixed_rsrc_ref_node *ref_node;
 	struct file *file;
 	__s32 __user *fds;
 	int fd, i, err;
@@ -7903,7 +7909,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 	done = 0;
 	fds = u64_to_user_ptr(up->fds);
 	while (nr_args) {
-		struct fixed_file_table *table;
+		struct fixed_rsrc_table *table;
 		unsigned index;
 
 		err = 0;
@@ -7956,9 +7962,9 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 
 	if (needs_switch) {
 		percpu_ref_kill(&data->node->refs);
-		io_sqe_files_set_node(data, ref_node);
+		io_sqe_rsrc_set_node(data, ref_node);
 	} else
-		destroy_fixed_file_ref_node(ref_node);
+		destroy_fixed_rsrc_ref_node(ref_node);
 
 	return done ? done : err;
 }
@@ -7966,7 +7972,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg,
 			       unsigned nr_args)
 {
-	struct io_uring_files_update up;
+	struct io_uring_rsrc_update up;
 
 	if (!ctx->file_data)
 		return -ENXIO;
@@ -9340,7 +9346,7 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
 	seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);
 	seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);
 	for (i = 0; has_lock && i < ctx->nr_user_files; i++) {
-		struct fixed_file_table *table;
+		struct fixed_rsrc_table *table;
 		struct file *f;
 
 		table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT];
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index d31a2a1..77de7c0 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -285,12 +285,13 @@ enum {
 	IORING_REGISTER_LAST
 };
 
-struct io_uring_files_update {
+struct io_uring_rsrc_update {
 	__u32 offset;
 	__u32 resv;
 	__aligned_u64 /* __s32 * */ fds;
 };
 
+#define io_uring_files_update	io_uring_rsrc_update
 #define IO_URING_OP_SUPPORTED	(1U << 0)
 
 struct io_uring_probe_op {
-- 
1.8.3.1

[PATCH v4 04/13] io_uring: generalize io_queue_rsrc_removal

[Bijan Mottahedeh]

Generalize io_queue_rsrc_removal to handle both files and buffers.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2c5d8c3..88baa13 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -195,13 +195,22 @@ struct io_mapped_ubuf {
 	unsigned long	acct_pages;
 };
 
+struct io_ring_ctx;
+
 struct io_rsrc_put {
 	struct list_head list;
-	struct file *file;
+	union {
+		void *rsrc;
+		struct file *file;
+		struct io_mapped_ubuf *buf;
+	};
 };
 
 struct fixed_rsrc_table {
-	struct file		**files;
+	union {
+		struct file		**files;
+		struct io_mapped_ubuf	*bufs;
+	};
 };
 
 struct fixed_rsrc_ref_node {
@@ -209,6 +218,8 @@ struct fixed_rsrc_ref_node {
 	struct list_head		node;
 	struct list_head		rsrc_list;
 	struct fixed_rsrc_data		*rsrc_data;
+	void				(*rsrc_put)(struct io_ring_ctx *ctx,
+						    struct io_rsrc_put *prsrc);
 	struct llist_node		llist;
 	bool				done;
 };
@@ -7557,8 +7568,9 @@ static int io_sqe_alloc_file_tables(struct fixed_rsrc_data *file_data,
 	return 1;
 }
 
-static void io_ring_file_put(struct io_ring_ctx *ctx, struct file *file)
+static void io_ring_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
 {
+	struct file *file = prsrc->file;
 #if defined(CONFIG_UNIX)
 	struct sock *sock = ctx->ring_sock->sk;
 	struct sk_buff_head list, *head = &sock->sk_receive_queue;
@@ -7627,7 +7639,7 @@ static void __io_rsrc_put_work(struct fixed_rsrc_ref_node *ref_node)
 
 	list_for_each_entry_safe(prsrc, tmp, &ref_node->rsrc_list, list) {
 		list_del(&prsrc->list);
-		io_ring_file_put(ctx, prsrc->file);
+		ref_node->rsrc_put(ctx, prsrc);
 		kfree(prsrc);
 	}
 
@@ -7706,6 +7718,7 @@ static struct fixed_rsrc_ref_node *alloc_fixed_file_ref_node(
 	INIT_LIST_HEAD(&ref_node->node);
 	INIT_LIST_HEAD(&ref_node->rsrc_list);
 	ref_node->rsrc_data = ctx->file_data;
+	ref_node->rsrc_put = io_ring_file_put;
 	ref_node->done = false;
 	return ref_node;
 }
@@ -7863,8 +7876,7 @@ static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
 #endif
 }
 
-static int io_queue_rsrc_removal(struct fixed_rsrc_data *data,
-				 struct file *rsrc)
+static int io_queue_rsrc_removal(struct fixed_rsrc_data *data, void *rsrc)
 {
 	struct io_rsrc_put *prsrc;
 	struct fixed_rsrc_ref_node *ref_node = data->node;
@@ -7873,7 +7885,7 @@ static int io_queue_rsrc_removal(struct fixed_rsrc_data *data,
 	if (!prsrc)
 		return -ENOMEM;
 
-	prsrc->file = rsrc;
+	prsrc->rsrc = rsrc;
 	list_add(&prsrc->list, &ref_node->rsrc_list);
 
 	return 0;
@@ -7882,7 +7894,7 @@ static int io_queue_rsrc_removal(struct fixed_rsrc_data *data,
 static inline int io_queue_file_removal(struct fixed_rsrc_data *data,
 					struct file *file)
 {
-	return io_queue_rsrc_removal(data, file);
+	return io_queue_rsrc_removal(data, (void *)file);
 }
 
 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
-- 
1.8.3.1

[PATCH v4 05/13] io_uring: separate ref_list from fixed_rsrc_data

[Bijan Mottahedeh]

Uplevel ref_list and make it common to all resources.  This is to
allow one common ref_list to be used for both files, and buffers
in upcoming patches.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c | 35 ++++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 88baa13..98e34eb 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -231,8 +231,6 @@ struct fixed_rsrc_data {
 	struct fixed_rsrc_ref_node	*node;
 	struct percpu_ref		refs;
 	struct completion		done;
-	struct list_head		ref_list;
-	spinlock_t			lock;
 };
 
 struct io_buffer {
@@ -400,6 +398,8 @@ struct io_ring_ctx {
 
 	struct delayed_work		rsrc_put_work;
 	struct llist_head		rsrc_put_llist;
+	struct list_head		rsrc_ref_list;
+	spinlock_t			rsrc_ref_lock;
 
 	struct work_struct		exit_work;
 	struct io_restriction		restrictions;
@@ -1332,6 +1332,8 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
 	INIT_LIST_HEAD(&ctx->timeout_list);
 	spin_lock_init(&ctx->inflight_lock);
 	INIT_LIST_HEAD(&ctx->inflight_list);
+	spin_lock_init(&ctx->rsrc_ref_lock);
+	INIT_LIST_HEAD(&ctx->rsrc_ref_list);
 	INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
 	init_llist_head(&ctx->rsrc_put_llist);
 	return ctx;
@@ -7263,13 +7265,14 @@ static void io_rsrc_ref_kill(struct percpu_ref *ref)
 	complete(&data->done);
 }
 
-static void io_sqe_rsrc_set_node(struct fixed_rsrc_data *rsrc_data,
+static void io_sqe_rsrc_set_node(struct io_ring_ctx *ctx,
+				 struct fixed_rsrc_data *rsrc_data,
 				 struct fixed_rsrc_ref_node *ref_node)
 {
-	spin_lock_bh(&rsrc_data->lock);
+	spin_lock_bh(&ctx->rsrc_ref_lock);
 	rsrc_data->node = ref_node;
-	list_add_tail(&ref_node->node, &rsrc_data->ref_list);
-	spin_unlock_bh(&rsrc_data->lock);
+	list_add_tail(&ref_node->node, &ctx->rsrc_ref_list);
+	spin_unlock_bh(&ctx->rsrc_ref_lock);
 	percpu_ref_get(&rsrc_data->refs);
 }
 
@@ -7286,9 +7289,9 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 	if (!backup_node)
 		return -ENOMEM;
 
-	spin_lock_bh(&data->lock);
+	spin_lock_bh(&ctx->rsrc_ref_lock);
 	ref_node = data->node;
-	spin_unlock_bh(&data->lock);
+	spin_unlock_bh(&ctx->rsrc_ref_lock);
 	if (ref_node)
 		percpu_ref_kill(&ref_node->refs);
 
@@ -7304,7 +7307,7 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 		if (ret < 0) {
 			percpu_ref_resurrect(&data->refs);
 			reinit_completion(&data->done);
-			io_sqe_rsrc_set_node(data, backup_node);
+			io_sqe_rsrc_set_node(ctx, data, backup_node);
 			return ret;
 		}
 	} while (1);
@@ -7678,11 +7681,11 @@ static void io_rsrc_data_ref_zero(struct percpu_ref *ref)
 	data = ref_node->rsrc_data;
 	ctx = data->ctx;
 
-	spin_lock_bh(&data->lock);
+	spin_lock_bh(&ctx->rsrc_ref_lock);
 	ref_node->done = true;
 
-	while (!list_empty(&data->ref_list)) {
-		ref_node = list_first_entry(&data->ref_list,
+	while (!list_empty(&ctx->rsrc_ref_list)) {
+		ref_node = list_first_entry(&ctx->rsrc_ref_list,
 					struct fixed_rsrc_ref_node, node);
 		/* recycle ref nodes in order */
 		if (!ref_node->done)
@@ -7690,7 +7693,7 @@ static void io_rsrc_data_ref_zero(struct percpu_ref *ref)
 		list_del(&ref_node->node);
 		first_add |= llist_add(&ref_node->llist, &ctx->rsrc_put_llist);
 	}
-	spin_unlock_bh(&data->lock);
+	spin_unlock_bh(&ctx->rsrc_ref_lock);
 
 	if (percpu_ref_is_dying(&data->refs))
 		delay = 0;
@@ -7751,8 +7754,6 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 		return -ENOMEM;
 	file_data->ctx = ctx;
 	init_completion(&file_data->done);
-	INIT_LIST_HEAD(&file_data->ref_list);
-	spin_lock_init(&file_data->lock);
 
 	nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE);
 	file_data->table = kcalloc(nr_tables, sizeof(*file_data->table),
@@ -7813,7 +7814,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 		return -ENOMEM;
 	}
 
-	io_sqe_rsrc_set_node(file_data, ref_node);
+	io_sqe_rsrc_set_node(ctx, file_data, ref_node);
 	return ret;
 out_fput:
 	for (i = 0; i < ctx->nr_user_files; i++) {
@@ -7974,7 +7975,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 
 	if (needs_switch) {
 		percpu_ref_kill(&data->node->refs);
-		io_sqe_rsrc_set_node(data, ref_node);
+		io_sqe_rsrc_set_node(ctx, data, ref_node);
 	} else
 		destroy_fixed_rsrc_ref_node(ref_node);
 
-- 
1.8.3.1

[PATCH v4 06/13] io_uring: split alloc_fixed_file_ref_node

[Bijan Mottahedeh]

Split alloc_fixed_file_ref_node into resource generic/specific parts,
to be leveraged for fixed buffers.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 98e34eb..1d04e82 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7704,7 +7704,7 @@ static void io_rsrc_data_ref_zero(struct percpu_ref *ref)
 		queue_delayed_work(system_wq, &ctx->rsrc_put_work, delay);
 }
 
-static struct fixed_rsrc_ref_node *alloc_fixed_file_ref_node(
+static struct fixed_rsrc_ref_node *alloc_fixed_rsrc_ref_node(
 			struct io_ring_ctx *ctx)
 {
 	struct fixed_rsrc_ref_node *ref_node;
@@ -7720,9 +7720,21 @@ static struct fixed_rsrc_ref_node *alloc_fixed_file_ref_node(
 	}
 	INIT_LIST_HEAD(&ref_node->node);
 	INIT_LIST_HEAD(&ref_node->rsrc_list);
+	ref_node->done = false;
+	return ref_node;
+}
+
+static struct fixed_rsrc_ref_node *alloc_fixed_file_ref_node(
+			struct io_ring_ctx *ctx)
+{
+	struct fixed_rsrc_ref_node *ref_node;
+
+	ref_node = alloc_fixed_rsrc_ref_node(ctx);
+	if (!ref_node)
+		return NULL;
+
 	ref_node->rsrc_data = ctx->file_data;
 	ref_node->rsrc_put = io_ring_file_put;
-	ref_node->done = false;
 	return ref_node;
 }
 
-- 
1.8.3.1

[PATCH v4 07/13] io_uring: add rsrc_ref locking routines

[Bijan Mottahedeh]

Encapsulate resource reference locking into separate routines.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1d04e82..61e87c4 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7265,14 +7265,24 @@ static void io_rsrc_ref_kill(struct percpu_ref *ref)
 	complete(&data->done);
 }
 
+static inline void io_rsrc_ref_lock(struct io_ring_ctx *ctx)
+{
+	spin_lock_bh(&ctx->rsrc_ref_lock);
+}
+
+static inline void io_rsrc_ref_unlock(struct io_ring_ctx *ctx)
+{
+	spin_unlock_bh(&ctx->rsrc_ref_lock);
+}
+
 static void io_sqe_rsrc_set_node(struct io_ring_ctx *ctx,
 				 struct fixed_rsrc_data *rsrc_data,
 				 struct fixed_rsrc_ref_node *ref_node)
 {
-	spin_lock_bh(&ctx->rsrc_ref_lock);
+	io_rsrc_ref_lock(ctx);
 	rsrc_data->node = ref_node;
 	list_add_tail(&ref_node->node, &ctx->rsrc_ref_list);
-	spin_unlock_bh(&ctx->rsrc_ref_lock);
+	io_rsrc_ref_unlock(ctx);
 	percpu_ref_get(&rsrc_data->refs);
 }
 
@@ -7289,9 +7299,9 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 	if (!backup_node)
 		return -ENOMEM;
 
-	spin_lock_bh(&ctx->rsrc_ref_lock);
+	io_rsrc_ref_lock(ctx);
 	ref_node = data->node;
-	spin_unlock_bh(&ctx->rsrc_ref_lock);
+	io_rsrc_ref_unlock(ctx);
 	if (ref_node)
 		percpu_ref_kill(&ref_node->refs);
 
@@ -7681,7 +7691,7 @@ static void io_rsrc_data_ref_zero(struct percpu_ref *ref)
 	data = ref_node->rsrc_data;
 	ctx = data->ctx;
 
-	spin_lock_bh(&ctx->rsrc_ref_lock);
+	io_rsrc_ref_lock(ctx);
 	ref_node->done = true;
 
 	while (!list_empty(&ctx->rsrc_ref_list)) {
@@ -7693,7 +7703,7 @@ static void io_rsrc_data_ref_zero(struct percpu_ref *ref)
 		list_del(&ref_node->node);
 		first_add |= llist_add(&ref_node->llist, &ctx->rsrc_put_llist);
 	}
-	spin_unlock_bh(&ctx->rsrc_ref_lock);
+	io_rsrc_ref_unlock(ctx);
 
 	if (percpu_ref_is_dying(&data->refs))
 		delay = 0;
-- 
1.8.3.1

[PATCH v4 08/13] io_uring: implement fixed buffers registration similar to fixed files

[Bijan Mottahedeh]

Apply fixed_rsrc functionality for fixed buffers support.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c | 234 +++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 198 insertions(+), 36 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 61e87c4..91be618 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -104,6 +104,14 @@
 #define IORING_MAX_RESTRICTIONS	(IORING_RESTRICTION_LAST + \
 				 IORING_REGISTER_LAST + IORING_OP_LAST)
 
+/*
+ * Shift of 7 is 128 entries, or exactly one page on 64-bit archs
+ */
+#define IORING_BUF_TABLE_SHIFT	7	/* struct io_mapped_ubuf */
+#define IORING_MAX_BUFS_TABLE	(1U << IORING_BUF_TABLE_SHIFT)
+#define IORING_BUF_TABLE_MASK	(IORING_MAX_BUFS_TABLE - 1)
+#define IORING_MAX_FIXED_BUFS	UIO_MAXIOV
+
 struct io_uring {
 	u32 head ____cacheline_aligned_in_smp;
 	u32 tail ____cacheline_aligned_in_smp;
@@ -336,8 +344,8 @@ struct io_ring_ctx {
 	unsigned		nr_user_files;
 
 	/* if used, fixed mapped user buffers */
+	struct fixed_rsrc_data	*buf_data;
 	unsigned		nr_user_bufs;
-	struct io_mapped_ubuf	*user_bufs;
 
 	struct user_struct	*user;
 
@@ -2958,6 +2966,15 @@ static void kiocb_done(struct kiocb *kiocb, ssize_t ret,
 		io_rw_done(kiocb, ret);
 }
 
+static inline struct io_mapped_ubuf *io_buf_from_index(struct io_ring_ctx *ctx,
+						       int index)
+{
+	struct fixed_rsrc_table *table;
+
+	table = &ctx->buf_data->table[index >> IORING_BUF_TABLE_SHIFT];
+	return &table->bufs[index & IORING_BUF_TABLE_MASK];
+}
+
 static ssize_t io_import_fixed(struct io_kiocb *req, int rw,
 			       struct iov_iter *iter)
 {
@@ -2971,7 +2988,7 @@ static ssize_t io_import_fixed(struct io_kiocb *req, int rw,
 	if (unlikely(buf_index >= ctx->nr_user_bufs))
 		return -EFAULT;
 	index = array_index_nospec(buf_index, ctx->nr_user_bufs);
-	imu = &ctx->user_bufs[index];
+	imu = io_buf_from_index(ctx, index);
 	buf_addr = req->rw.addr;
 
 	/* overflow */
@@ -8322,28 +8339,71 @@ static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
 	return pages;
 }
 
-static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
+static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf *imu)
 {
-	int i, j;
+	unsigned int i;
 
-	if (!ctx->user_bufs)
-		return -ENXIO;
+	for (i = 0; i < imu->nr_bvecs; i++)
+		unpin_user_page(imu->bvec[i].bv_page);
 
-	for (i = 0; i < ctx->nr_user_bufs; i++) {
-		struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
+	if (imu->acct_pages)
+		io_unaccount_mem(ctx, imu->nr_bvecs, ACCT_PINNED);
+	kvfree(imu->bvec);
+	imu->nr_bvecs = 0;
+}
 
-		for (j = 0; j < imu->nr_bvecs; j++)
-			unpin_user_page(imu->bvec[j].bv_page);
+static void io_buffers_unmap(struct io_ring_ctx *ctx)
+{
+	unsigned int i;
+	struct io_mapped_ubuf *imu;
 
-		if (imu->acct_pages)
-			io_unaccount_mem(ctx, imu->acct_pages, ACCT_PINNED);
-		kvfree(imu->bvec);
-		imu->nr_bvecs = 0;
+	for (i = 0; i < ctx->nr_user_bufs; i++) {
+		imu = io_buf_from_index(ctx, i);
+		io_buffer_unmap(ctx, imu);
 	}
+}
+
+static void io_buffers_map_free(struct io_ring_ctx *ctx)
+{
+	struct fixed_rsrc_data *data = ctx->buf_data;
+	unsigned int nr_tables, i;
+
+	if (!data)
+		return;
 
-	kfree(ctx->user_bufs);
-	ctx->user_bufs = NULL;
+	nr_tables = DIV_ROUND_UP(ctx->nr_user_bufs, IORING_MAX_BUFS_TABLE);
+	for (i = 0; i < nr_tables; i++)
+		kfree(data->table[i].bufs);
+	kfree(data->table);
+	percpu_ref_exit(&data->refs);
+	kfree(data);
+	ctx->buf_data = NULL;
 	ctx->nr_user_bufs = 0;
+}
+
+static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
+{
+	struct fixed_rsrc_data *data = ctx->buf_data;
+	struct fixed_rsrc_ref_node *ref_node = NULL;
+
+	if (!data)
+		return -ENXIO;
+
+	io_rsrc_ref_lock(ctx);
+	ref_node = data->node;
+	io_rsrc_ref_unlock(ctx);
+	if (ref_node)
+		percpu_ref_kill(&ref_node->refs);
+
+	percpu_ref_kill(&data->refs);
+
+	/* wait for all refs nodes to complete */
+	flush_delayed_work(&ctx->rsrc_put_work);
+	wait_for_completion(&data->done);
+
+	io_buffers_unmap(ctx);
+	io_buffers_map_free(ctx);
+
 	return 0;
 }
 
@@ -8396,7 +8456,9 @@ static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
 
 	/* check previously registered pages */
 	for (i = 0; i < ctx->nr_user_bufs; i++) {
-		struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
+		struct io_mapped_ubuf *imu;
+
+		imu = io_buf_from_index(ctx, i);
 
 		for (j = 0; j < imu->nr_bvecs; j++) {
 			if (!PageCompound(imu->bvec[j].bv_page))
@@ -8531,19 +8593,79 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
 	return ret;
 }
 
-static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
+static void io_free_buf_tables(struct fixed_rsrc_data *buf_data,
+			       unsigned int nr_tables)
 {
-	if (ctx->user_bufs)
-		return -EBUSY;
-	if (!nr_args || nr_args > UIO_MAXIOV)
-		return -EINVAL;
+	int i;
 
-	ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf),
-					GFP_KERNEL);
-	if (!ctx->user_bufs)
-		return -ENOMEM;
+	for (i = 0; i < nr_tables; i++) {
+		struct fixed_rsrc_table *table = &buf_data->table[i];
 
-	return 0;
+		kfree(table->bufs);
+	}
+}
+
+static int io_alloc_buf_tables(struct fixed_rsrc_data *buf_data,
+			       unsigned int nr_tables, unsigned int nr_bufs)
+{
+	int i;
+
+	for (i = 0; i < nr_tables; i++) {
+		struct fixed_rsrc_table *table = &buf_data->table[i];
+		unsigned int this_bufs;
+
+		this_bufs = min(nr_bufs, IORING_MAX_BUFS_TABLE);
+		table->bufs = kcalloc(this_bufs, sizeof(struct io_mapped_ubuf),
+				      GFP_KERNEL);
+		if (!table->bufs)
+			break;
+		nr_bufs -= this_bufs;
+	}
+
+	if (i == nr_tables)
+		return 0;
+
+	io_free_buf_tables(buf_data, i);
+	return 1;
+}
+
+static struct fixed_rsrc_data *io_buffers_map_alloc(struct io_ring_ctx *ctx,
+						    unsigned int nr_args)
+{
+	unsigned int nr_tables;
+	struct fixed_rsrc_data *buf_data;
+	int ret = -ENOMEM;
+
+	if (!nr_args || nr_args > IORING_MAX_FIXED_BUFS)
+		return ERR_PTR(-EINVAL);
+
+	buf_data = kzalloc(sizeof(*ctx->buf_data), GFP_KERNEL);
+	if (!buf_data)
+		return ERR_PTR(-ENOMEM);
+	buf_data->ctx = ctx;
+	init_completion(&buf_data->done);
+
+	nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_BUFS_TABLE);
+	buf_data->table = kcalloc(nr_tables, sizeof(*buf_data->table),
+				  GFP_KERNEL);
+	if (!buf_data->table)
+		goto out_free;
+
+	if (percpu_ref_init(&buf_data->refs, io_rsrc_ref_kill,
+			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
+		goto out_free;
+
+	if (io_alloc_buf_tables(buf_data, nr_tables, nr_args))
+		goto out_ref;
+
+	return buf_data;
+
+out_ref:
+	percpu_ref_exit(&buf_data->refs);
+out_free:
+	kfree(buf_data->table);
+	kfree(buf_data);
+	return ERR_PTR(ret);
 }
 
 static int io_buffer_validate(struct iovec *iov)
@@ -8563,39 +8685,78 @@ static int io_buffer_validate(struct iovec *iov)
 	return 0;
 }
 
+static void io_ring_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
+{
+	io_buffer_unmap(ctx, prsrc->buf);
+}
+
+static struct fixed_rsrc_ref_node *alloc_fixed_buf_ref_node(
+			struct io_ring_ctx *ctx)
+{
+	struct fixed_rsrc_ref_node *ref_node;
+
+	ref_node = alloc_fixed_rsrc_ref_node(ctx);
+	ref_node->rsrc_data = ctx->buf_data;
+	ref_node->rsrc_put = io_ring_buf_put;
+	return ref_node;
+}
+
 static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 				   unsigned int nr_args)
 {
 	int i, ret;
 	struct iovec iov;
 	struct page *last_hpage = NULL;
+	struct fixed_rsrc_ref_node *ref_node;
+	struct fixed_rsrc_data *buf_data;
 
-	ret = io_buffers_map_alloc(ctx, nr_args);
-	if (ret)
-		return ret;
+	if (ctx->nr_user_bufs)
+		return -EBUSY;
 
-	for (i = 0; i < nr_args; i++) {
-		struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
+	buf_data = io_buffers_map_alloc(ctx, nr_args);
+	if (IS_ERR(buf_data))
+		return PTR_ERR(buf_data);
+
+	for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
+		struct io_mapped_ubuf *imu;
 
 		ret = io_copy_iov(ctx, &iov, arg, i);
 		if (ret)
 			break;
 
+		/* allow sparse sets */
+		if (!iov.iov_base && !iov.iov_len)
+			continue;
+
 		ret = io_buffer_validate(&iov);
 		if (ret)
 			break;
 
+		imu = io_buf_from_index(ctx, i);
+
 		ret = io_sqe_buffer_register(ctx, &iov, imu, &last_hpage);
 		if (ret)
 			break;
+	}
 
-		ctx->nr_user_bufs++;
+	ctx->buf_data = buf_data;
+	if (ret) {
+		io_sqe_buffers_unregister(ctx);
+		return ret;
 	}
 
-	if (ret)
+	ref_node = alloc_fixed_buf_ref_node(ctx);
+	if (IS_ERR(ref_node)) {
 		io_sqe_buffers_unregister(ctx);
+		return PTR_ERR(ref_node);
+	}
 
-	return ret;
+	buf_data->node = ref_node;
+	io_rsrc_ref_lock(ctx);
+	list_add(&ref_node->node, &ctx->rsrc_ref_list);
+	io_rsrc_ref_unlock(ctx);
+	percpu_ref_get(&buf_data->refs);
+	return 0;
 }
 
 static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
@@ -9393,7 +9554,7 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
 	}
 	seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs);
 	for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) {
-		struct io_mapped_ubuf *buf = &ctx->user_bufs[i];
+		struct io_mapped_ubuf *buf = io_buf_from_index(ctx, i);
 
 		seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf,
 						(unsigned int) buf->len);
@@ -9908,6 +10069,7 @@ static bool io_register_op_must_quiesce(int op)
 	switch (op) {
 	case IORING_UNREGISTER_FILES:
 	case IORING_REGISTER_FILES_UPDATE:
+	case IORING_UNREGISTER_BUFFERS:
 	case IORING_REGISTER_PROBE:
 	case IORING_REGISTER_PERSONALITY:
 	case IORING_UNREGISTER_PERSONALITY:
-- 
1.8.3.1

[PATCH v4 09/13] io_uring: create common fixed_rsrc_ref_node handling routines

[Bijan Mottahedeh]

Create common routines to be used for both files/buffers registration.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c | 47 ++++++++++++++++++++++++-----------------------
 1 file changed, 24 insertions(+), 23 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 91be618..fbff8480 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7303,15 +7303,12 @@ static void io_sqe_rsrc_set_node(struct io_ring_ctx *ctx,
 	percpu_ref_get(&rsrc_data->refs);
 }
 
-static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
+static int io_rsrc_ref_quiesce(struct fixed_rsrc_data *data,
+			       struct io_ring_ctx *ctx)
 {
-	struct fixed_rsrc_data *data = ctx->file_data;
 	struct fixed_rsrc_ref_node *backup_node, *ref_node = NULL;
-	unsigned nr_tables, i;
 	int ret;
 
-	if (!data)
-		return -ENXIO;
 	backup_node = alloc_fixed_file_ref_node(ctx);
 	if (!backup_node)
 		return -ENOMEM;
@@ -7339,6 +7336,23 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 		}
 	} while (1);
 
+	destroy_fixed_rsrc_ref_node(backup_node);
+	return 0;
+}
+
+static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
+{
+	struct fixed_rsrc_data *data = ctx->file_data;
+	unsigned int nr_tables, i;
+	int ret;
+
+	if (!data)
+		return -ENXIO;
+
+	ret = io_rsrc_ref_quiesce(data, ctx);
+	if (ret)
+		return ret;
+
 	__io_sqe_files_unregister(ctx);
 	nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE);
 	for (i = 0; i < nr_tables; i++)
@@ -7348,7 +7362,6 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 	kfree(data);
 	ctx->file_data = NULL;
 	ctx->nr_user_files = 0;
-	destroy_fixed_rsrc_ref_node(backup_node);
 	return 0;
 }
 
@@ -8384,22 +8397,14 @@ static void io_buffers_map_free(struct io_ring_ctx *ctx)
 static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
 {
 	struct fixed_rsrc_data *data = ctx->buf_data;
-	struct fixed_rsrc_ref_node *ref_node = NULL;
+	int ret;
 
 	if (!data)
 		return -ENXIO;
 
-	io_rsrc_ref_lock(ctx);
-	ref_node = data->node;
-	io_rsrc_ref_unlock(ctx);
-	if (ref_node)
-		percpu_ref_kill(&ref_node->refs);
-
-	percpu_ref_kill(&data->refs);
-
-	/* wait for all refs nodes to complete */
-	flush_delayed_work(&ctx->rsrc_put_work);
-	wait_for_completion(&data->done);
+	ret = io_rsrc_ref_quiesce(data, ctx);
+	if (ret)
+		return ret;
 
 	io_buffers_unmap(ctx);
 	io_buffers_map_free(ctx);
@@ -8751,11 +8756,7 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 		return PTR_ERR(ref_node);
 	}
 
-	buf_data->node = ref_node;
-	io_rsrc_ref_lock(ctx);
-	list_add(&ref_node->node, &ctx->rsrc_ref_list);
-	io_rsrc_ref_unlock(ctx);
-	percpu_ref_get(&buf_data->refs);
+	io_sqe_rsrc_set_node(ctx, buf_data, ref_node);
 	return 0;
 }
 
-- 
1.8.3.1

Re: [PATCH v4 09/13] io_uring: create common fixed_rsrc_ref_node handling routines

[Bijan Mottahedeh]

On 1/6/2021 12:39 PM, Bijan Mottahedeh wrote:
> Create common routines to be used for both files/buffers registration.
> 
> Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
> ---
>   fs/io_uring.c | 47 ++++++++++++++++++++++++-----------------------
>   1 file changed, 24 insertions(+), 23 deletions(-)
> 
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 91be618..fbff8480 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -7303,15 +7303,12 @@ static void io_sqe_rsrc_set_node(struct io_ring_ctx *ctx,
>   	percpu_ref_get(&rsrc_data->refs);
>   }
>   
> -static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
> +static int io_rsrc_ref_quiesce(struct fixed_rsrc_data *data,
> +			       struct io_ring_ctx *ctx)
>   {
> -	struct fixed_rsrc_data *data = ctx->file_data;
>   	struct fixed_rsrc_ref_node *backup_node, *ref_node = NULL;
> -	unsigned nr_tables, i;
>   	int ret;
>   
> -	if (!data)
> -		return -ENXIO;
>   	backup_node = alloc_fixed_file_ref_node(ctx);
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I introduced a bug here; I call the file allocator directly.  I've fixed 
it by passing in the proper allocator.  Will send it with the next patch 
set.


>   	if (!backup_node)
>   		return -ENOMEM;
> @@ -7339,6 +7336,23 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
>   		}
>   	} while (1);
>   
> +	destroy_fixed_rsrc_ref_node(backup_node);
> +	return 0;
> +}
> +
> +static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
> +{
> +	struct fixed_rsrc_data *data = ctx->file_data;
> +	unsigned int nr_tables, i;
> +	int ret;
> +
> +	if (!data)
> +		return -ENXIO;
> +
> +	ret = io_rsrc_ref_quiesce(data, ctx);
> +	if (ret)
> +		return ret;
> +
>   	__io_sqe_files_unregister(ctx);
>   	nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE);
>   	for (i = 0; i < nr_tables; i++)
> @@ -7348,7 +7362,6 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
>   	kfree(data);
>   	ctx->file_data = NULL;
>   	ctx->nr_user_files = 0;
> -	destroy_fixed_rsrc_ref_node(backup_node);
>   	return 0;
>   }
>   
> @@ -8384,22 +8397,14 @@ static void io_buffers_map_free(struct io_ring_ctx *ctx)
>   static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
>   {
>   	struct fixed_rsrc_data *data = ctx->buf_data;
> -	struct fixed_rsrc_ref_node *ref_node = NULL;
> +	int ret;
>   
>   	if (!data)
>   		return -ENXIO;
>   
> -	io_rsrc_ref_lock(ctx);
> -	ref_node = data->node;
> -	io_rsrc_ref_unlock(ctx);
> -	if (ref_node)
> -		percpu_ref_kill(&ref_node->refs);
> -
> -	percpu_ref_kill(&data->refs);
> -
> -	/* wait for all refs nodes to complete */
> -	flush_delayed_work(&ctx->rsrc_put_work);
> -	wait_for_completion(&data->done);
> +	ret = io_rsrc_ref_quiesce(data, ctx);
> +	if (ret)
> +		return ret;
>   
>   	io_buffers_unmap(ctx);
>   	io_buffers_map_free(ctx);
> @@ -8751,11 +8756,7 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
>   		return PTR_ERR(ref_node);
>   	}
>   
> -	buf_data->node = ref_node;
> -	io_rsrc_ref_lock(ctx);
> -	list_add(&ref_node->node, &ctx->rsrc_ref_list);
> -	io_rsrc_ref_unlock(ctx);
> -	percpu_ref_get(&buf_data->refs);
> +	io_sqe_rsrc_set_node(ctx, buf_data, ref_node);
>   	return 0;
>   }
>   
> 

[PATCH v4 10/13] io_uring: generalize files_update functionlity to rsrc_update

[Bijan Mottahedeh]

Generalize files_update functionality to rsrc_update in order to
leverage it for buffers updates.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c                 | 19 ++++++++++++++-----
 include/uapi/linux/io_uring.h |  6 +++++-
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index fbff8480..b956029 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5951,7 +5951,7 @@ static int io_async_cancel(struct io_kiocb *req)
 }
 
 static int io_rsrc_update_prep(struct io_kiocb *req,
-				const struct io_uring_sqe *sqe)
+			       const struct io_uring_sqe *sqe)
 {
 	if (unlikely(req->ctx->flags & IORING_SETUP_SQPOLL))
 		return -EINVAL;
@@ -5968,8 +5968,11 @@ static int io_rsrc_update_prep(struct io_kiocb *req,
 	return 0;
 }
 
-static int io_files_update(struct io_kiocb *req, bool force_nonblock,
-			   struct io_comp_state *cs)
+static int io_rsrc_update(struct io_kiocb *req, bool force_nonblock,
+			  struct io_comp_state *cs,
+			  int (*update)(struct io_ring_ctx *ctx,
+					struct io_uring_rsrc_update *up,
+					unsigned int nr_args))
 {
 	struct io_ring_ctx *ctx = req->ctx;
 	struct io_uring_rsrc_update up;
@@ -5979,10 +5982,10 @@ static int io_files_update(struct io_kiocb *req, bool force_nonblock,
 		return -EAGAIN;
 
 	up.offset = req->rsrc_update.offset;
-	up.fds = req->rsrc_update.arg;
+	up.rsrc = req->rsrc_update.arg;
 
 	mutex_lock(&ctx->uring_lock);
-	ret = __io_sqe_files_update(ctx, &up, req->rsrc_update.nr_args);
+	ret = (*update)(ctx, &up, req->rsrc_update.nr_args);
 	mutex_unlock(&ctx->uring_lock);
 
 	if (ret < 0)
@@ -5991,6 +5994,12 @@ static int io_files_update(struct io_kiocb *req, bool force_nonblock,
 	return 0;
 }
 
+static int io_files_update(struct io_kiocb *req, bool force_nonblock,
+			   struct io_comp_state *cs)
+{
+	return io_rsrc_update(req, force_nonblock, cs, __io_sqe_files_update);
+}
+
 static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	switch (req->opcode) {
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 77de7c0..f51190b 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -288,7 +288,11 @@ enum {
 struct io_uring_rsrc_update {
 	__u32 offset;
 	__u32 resv;
-	__aligned_u64 /* __s32 * */ fds;
+	union {
+		__aligned_u64 /* __s32 * */ fds;
+		__aligned_u64 /* __s32 * */ iovs;
+		__aligned_u64 /* __s32 * */ rsrc;
+	};
 };
 
 #define io_uring_files_update	io_uring_rsrc_update
-- 
1.8.3.1

[PATCH v4 11/13] io_uring: support buffer registration updates

[Bijan Mottahedeh]

Introduce IORING_REGISTER_BUFFERS_UPDATE and IORING_OP_BUFFERS_UPDATE,
consistent with file registration update.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c                 | 128 +++++++++++++++++++++++++++++++++++++++++-
 include/uapi/linux/io_uring.h |   2 +
 2 files changed, 128 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index b956029..dcbf9b1 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1009,6 +1009,9 @@ struct io_op_def {
 		.work_flags		= IO_WQ_WORK_MM | IO_WQ_WORK_FILES |
 						IO_WQ_WORK_FS | IO_WQ_WORK_BLKCG,
 	},
+	[IORING_OP_BUFFERS_UPDATE] = {
+		.work_flags		= IO_WQ_WORK_MM,
+	},
 };
 
 enum io_mem_account {
@@ -1035,6 +1038,9 @@ static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
 static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 				 struct io_uring_rsrc_update *ip,
 				 unsigned nr_args);
+static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
+				   struct io_uring_rsrc_update *up,
+				   unsigned int nr_args);
 static void __io_clean_op(struct io_kiocb *req);
 static struct file *io_file_get(struct io_submit_state *state,
 				struct io_kiocb *req, int fd, bool fixed);
@@ -6000,6 +6006,12 @@ static int io_files_update(struct io_kiocb *req, bool force_nonblock,
 	return io_rsrc_update(req, force_nonblock, cs, __io_sqe_files_update);
 }
 
+static int io_buffers_update(struct io_kiocb *req, bool force_nonblock,
+			     struct io_comp_state *cs)
+{
+	return io_rsrc_update(req, force_nonblock, cs, __io_sqe_buffers_update);
+}
+
 static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	switch (req->opcode) {
@@ -6071,11 +6083,13 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		return io_renameat_prep(req, sqe);
 	case IORING_OP_UNLINKAT:
 		return io_unlinkat_prep(req, sqe);
+	case IORING_OP_BUFFERS_UPDATE:
+		return io_rsrc_update_prep(req, sqe);
 	}
 
 	printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
 			req->opcode);
-	return-EINVAL;
+	return -EINVAL;
 }
 
 static int io_req_defer_prep(struct io_kiocb *req,
@@ -6330,6 +6344,9 @@ static int io_issue_sqe(struct io_kiocb *req, bool force_nonblock,
 	case IORING_OP_UNLINKAT:
 		ret = io_unlinkat(req, force_nonblock);
 		break;
+	case IORING_OP_BUFFERS_UPDATE:
+		ret = io_buffers_update(req, force_nonblock, cs);
+		break;
 	default:
 		ret = -EINVAL;
 		break;
@@ -8037,8 +8054,9 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 	if (needs_switch) {
 		percpu_ref_kill(&data->node->refs);
 		io_sqe_rsrc_set_node(ctx, data, ref_node);
-	} else
+	} else {
 		destroy_fixed_rsrc_ref_node(ref_node);
+	}
 
 	return done ? done : err;
 }
@@ -8371,6 +8389,7 @@ static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf *imu)
 	if (imu->acct_pages)
 		io_unaccount_mem(ctx, imu->nr_bvecs, ACCT_PINNED);
 	kvfree(imu->bvec);
+	imu->bvec = NULL;
 	imu->nr_bvecs = 0;
 }
 
@@ -8574,6 +8593,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
 		if (pret > 0)
 			unpin_user_pages(pages, pret);
 		kvfree(imu->bvec);
+		imu->bvec = NULL;
 		goto done;
 	}
 
@@ -8702,6 +8722,8 @@ static int io_buffer_validate(struct iovec *iov)
 static void io_ring_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
 {
 	io_buffer_unmap(ctx, prsrc->buf);
+	kvfree(prsrc->buf);
+	prsrc->buf = NULL;
 }
 
 static struct fixed_rsrc_ref_node *alloc_fixed_buf_ref_node(
@@ -8769,6 +8791,104 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 	return 0;
 }
 
+static inline int io_queue_buffer_removal(struct fixed_rsrc_data *data,
+					  struct io_mapped_ubuf *imu)
+{
+	return io_queue_rsrc_removal(data, (void *)imu);
+}
+
+static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
+				   struct io_uring_rsrc_update *up,
+				   unsigned int nr_args)
+{
+	struct fixed_rsrc_data *data = ctx->buf_data;
+	struct fixed_rsrc_ref_node *ref_node;
+	struct io_mapped_ubuf *imu;
+	struct iovec iov;
+	struct iovec __user *iovs;
+	struct page *last_hpage = NULL;
+	__u32 done;
+	int i, err;
+	bool needs_switch = false;
+
+	if (check_add_overflow(up->offset, nr_args, &done))
+		return -EOVERFLOW;
+	if (done > ctx->nr_user_bufs)
+		return -EINVAL;
+
+	ref_node = alloc_fixed_buf_ref_node(ctx);
+	if (IS_ERR(ref_node))
+		return PTR_ERR(ref_node);
+
+	done = 0;
+	iovs = u64_to_user_ptr(up->iovs);
+	while (nr_args) {
+		struct fixed_rsrc_table *table;
+		unsigned int index;
+
+		err = 0;
+		if (copy_from_user(&iov, &iovs[done], sizeof(iov))) {
+			err = -EFAULT;
+			break;
+		}
+		i = array_index_nospec(up->offset, ctx->nr_user_bufs);
+		table = &ctx->buf_data->table[i >> IORING_BUF_TABLE_SHIFT];
+		index = i & IORING_BUF_TABLE_MASK;
+		imu = &table->bufs[index];
+		if (table->bufs[index].ubuf) {
+			struct io_mapped_ubuf *dup;
+
+			dup = kmemdup(imu, sizeof(*imu), GFP_KERNEL);
+			if (!dup) {
+				err = -ENOMEM;
+				break;
+			}
+			err = io_queue_buffer_removal(data, dup);
+			if (err)
+				break;
+			memset(imu, 0, sizeof(*imu));
+			needs_switch = true;
+		}
+		if (!io_buffer_validate(&iov)) {
+			err = io_sqe_buffer_register(ctx, &iov, imu,
+						     &last_hpage);
+			if (err) {
+				memset(imu, 0, sizeof(*imu));
+				break;
+			}
+		}
+		nr_args--;
+		done++;
+		up->offset++;
+	}
+
+	if (needs_switch) {
+		percpu_ref_kill(&data->node->refs);
+		io_sqe_rsrc_set_node(ctx, data, ref_node);
+	} else {
+		destroy_fixed_rsrc_ref_node(ref_node);
+	}
+
+	return done ? done : err;
+}
+
+static int io_sqe_buffers_update(struct io_ring_ctx *ctx, void __user *arg,
+				 unsigned int nr_args)
+{
+	struct io_uring_rsrc_update up;
+
+	if (!ctx->buf_data)
+		return -ENXIO;
+	if (!nr_args)
+		return -EINVAL;
+	if (copy_from_user(&up, arg, sizeof(up)))
+		return -EFAULT;
+	if (up.resv)
+		return -EINVAL;
+
+	return __io_sqe_buffers_update(ctx, &up, nr_args);
+}
+
 static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
 {
 	__s32 __user *fds = arg;
@@ -10080,6 +10200,7 @@ static bool io_register_op_must_quiesce(int op)
 	case IORING_UNREGISTER_FILES:
 	case IORING_REGISTER_FILES_UPDATE:
 	case IORING_UNREGISTER_BUFFERS:
+	case IORING_REGISTER_BUFFERS_UPDATE:
 	case IORING_REGISTER_PROBE:
 	case IORING_REGISTER_PERSONALITY:
 	case IORING_UNREGISTER_PERSONALITY:
@@ -10155,6 +10276,9 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
 			break;
 		ret = io_sqe_buffers_unregister(ctx);
 		break;
+	case IORING_REGISTER_BUFFERS_UPDATE:
+		ret = io_sqe_buffers_update(ctx, arg, nr_args);
+		break;
 	case IORING_REGISTER_FILES:
 		ret = io_sqe_files_register(ctx, arg, nr_args);
 		break;
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index f51190b..b289ef8 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -137,6 +137,7 @@ enum {
 	IORING_OP_SHUTDOWN,
 	IORING_OP_RENAMEAT,
 	IORING_OP_UNLINKAT,
+	IORING_OP_BUFFERS_UPDATE,
 
 	/* this goes last, obviously */
 	IORING_OP_LAST,
@@ -280,6 +281,7 @@ enum {
 	IORING_UNREGISTER_PERSONALITY		= 10,
 	IORING_REGISTER_RESTRICTIONS		= 11,
 	IORING_REGISTER_ENABLE_RINGS		= 12,
+	IORING_REGISTER_BUFFERS_UPDATE		= 13,
 
 	/* this goes last */
 	IORING_REGISTER_LAST
-- 
1.8.3.1

[PATCH v4 12/13] io_uring: create common fixed_rsrc_data allocation routines

[Bijan Mottahedeh]

Create common alloc/free fixed_rsrc_data routines for both files and
buffers.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c | 75 ++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 41 insertions(+), 34 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index dcbf9b1..ea708ec 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7366,6 +7366,33 @@ static int io_rsrc_ref_quiesce(struct fixed_rsrc_data *data,
 	return 0;
 }
 
+static struct fixed_rsrc_data *alloc_fixed_rsrc_data(struct io_ring_ctx *ctx)
+{
+	struct fixed_rsrc_data *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return ERR_PTR(-ENOMEM);
+
+	data->ctx = ctx;
+	init_completion(&data->done);
+
+	if (percpu_ref_init(&data->refs, io_rsrc_ref_kill,
+			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
+		kfree(data);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return data;
+}
+
+static void free_fixed_rsrc_data(struct fixed_rsrc_data *data)
+{
+	percpu_ref_exit(&data->refs);
+	kfree(data->table);
+	kfree(data);
+}
+
 static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 {
 	struct fixed_rsrc_data *data = ctx->file_data;
@@ -7383,9 +7410,7 @@ static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 	nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE);
 	for (i = 0; i < nr_tables; i++)
 		kfree(data->table[i].files);
-	kfree(data->table);
-	percpu_ref_exit(&data->refs);
-	kfree(data);
+	free_fixed_rsrc_data(ctx->file_data);
 	ctx->file_data = NULL;
 	ctx->nr_user_files = 0;
 	return 0;
@@ -7827,11 +7852,9 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 	if (nr_args > IORING_MAX_FIXED_FILES)
 		return -EMFILE;
 
-	file_data = kzalloc(sizeof(*ctx->file_data), GFP_KERNEL);
-	if (!file_data)
-		return -ENOMEM;
-	file_data->ctx = ctx;
-	init_completion(&file_data->done);
+	file_data = alloc_fixed_rsrc_data(ctx);
+	if (IS_ERR(file_data))
+		return PTR_ERR(ref_node);
 
 	nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE);
 	file_data->table = kcalloc(nr_tables, sizeof(*file_data->table),
@@ -7839,12 +7862,8 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 	if (!file_data->table)
 		goto out_free;
 
-	if (percpu_ref_init(&file_data->refs, io_rsrc_ref_kill,
-				PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
-		goto out_free;
-
 	if (io_sqe_alloc_file_tables(file_data, nr_tables, nr_args))
-		goto out_ref;
+		goto out_free;
 	ctx->file_data = file_data;
 
 	for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
@@ -7903,11 +7922,8 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 	for (i = 0; i < nr_tables; i++)
 		kfree(file_data->table[i].files);
 	ctx->nr_user_files = 0;
-out_ref:
-	percpu_ref_exit(&file_data->refs);
 out_free:
-	kfree(file_data->table);
-	kfree(file_data);
+	free_fixed_rsrc_data(ctx->file_data);
 	ctx->file_data = NULL;
 	return ret;
 }
@@ -8673,32 +8689,23 @@ static struct fixed_rsrc_data *io_buffers_map_alloc(struct io_ring_ctx *ctx,
 	if (!nr_args || nr_args > IORING_MAX_FIXED_BUFS)
 		return ERR_PTR(-EINVAL);
 
-	buf_data = kzalloc(sizeof(*ctx->buf_data), GFP_KERNEL);
-	if (!buf_data)
-		return ERR_PTR(-ENOMEM);
-	buf_data->ctx = ctx;
-	init_completion(&buf_data->done);
+	buf_data = alloc_fixed_rsrc_data(ctx);
+	if (IS_ERR(buf_data))
+		return buf_data;
 
 	nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_BUFS_TABLE);
 	buf_data->table = kcalloc(nr_tables, sizeof(*buf_data->table),
 				  GFP_KERNEL);
 	if (!buf_data->table)
-		goto out_free;
-
-	if (percpu_ref_init(&buf_data->refs, io_rsrc_ref_kill,
-			    PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
-		goto out_free;
+		goto out;
 
 	if (io_alloc_buf_tables(buf_data, nr_tables, nr_args))
-		goto out_ref;
+		goto out;
 
 	return buf_data;
-
-out_ref:
-	percpu_ref_exit(&buf_data->refs);
-out_free:
-	kfree(buf_data->table);
-	kfree(buf_data);
+out:
+	free_fixed_rsrc_data(ctx->buf_data);
+	ctx->buf_data = NULL;
 	return ERR_PTR(ret);
 }
 
-- 
1.8.3.1

[PATCH v4 13/13] io_uring: support buffer registration sharing

[Bijan Mottahedeh]

Implement buffer sharing among multiple rings.

A ring shares its (future) buffer registrations at setup time with
IORING_SETUP_SHARE_BUF. A ring attaches to another ring's buffer
registration at setup time with IORING_SETUP_ATTACH_BUF, after
authenticating with the buffer registration owner's fd. Any updates to
the owner's buffer registrations become immediately available to the
attached rings.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
---
 fs/io_uring.c                 | 85 +++++++++++++++++++++++++++++++++++++++++--
 include/uapi/linux/io_uring.h |  2 +
 2 files changed, 83 insertions(+), 4 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ea708ec..08ca435e 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8438,6 +8438,13 @@ static void io_buffers_map_free(struct io_ring_ctx *ctx)
 	ctx->nr_user_bufs = 0;
 }
 
+static void io_detach_buf_data(struct io_ring_ctx *ctx)
+{
+	percpu_ref_put(&ctx->buf_data->refs);
+	ctx->buf_data = NULL;
+	ctx->nr_user_bufs = 0;
+}
+
 static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
 {
 	struct fixed_rsrc_data *data = ctx->buf_data;
@@ -8446,6 +8453,11 @@ static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
 	if (!data)
 		return -ENXIO;
 
+	if (ctx->flags & IORING_SETUP_ATTACH_BUF) {
+		io_detach_buf_data(ctx);
+		return 0;
+	}
+
 	ret = io_rsrc_ref_quiesce(data, ctx);
 	if (ret)
 		return ret;
@@ -8689,9 +8701,13 @@ static struct fixed_rsrc_data *io_buffers_map_alloc(struct io_ring_ctx *ctx,
 	if (!nr_args || nr_args > IORING_MAX_FIXED_BUFS)
 		return ERR_PTR(-EINVAL);
 
-	buf_data = alloc_fixed_rsrc_data(ctx);
-	if (IS_ERR(buf_data))
-		return buf_data;
+	if (ctx->buf_data) {
+		buf_data = ctx->buf_data;
+	} else {
+		buf_data = alloc_fixed_rsrc_data(ctx);
+		if (IS_ERR(buf_data))
+			return buf_data;
+	}
 
 	nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_BUFS_TABLE);
 	buf_data->table = kcalloc(nr_tables, sizeof(*buf_data->table),
@@ -8756,9 +8772,17 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 	if (ctx->nr_user_bufs)
 		return -EBUSY;
 
+	if (ctx->flags & IORING_SETUP_ATTACH_BUF) {
+		if (!ctx->buf_data)
+			return -EFAULT;
+		ctx->nr_user_bufs = ctx->buf_data->ctx->nr_user_bufs;
+		return 0;
+	}
+
 	buf_data = io_buffers_map_alloc(ctx, nr_args);
 	if (IS_ERR(buf_data))
 		return PTR_ERR(buf_data);
+	ctx->buf_data = buf_data;
 
 	for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
 		struct io_mapped_ubuf *imu;
@@ -8782,7 +8806,6 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 			break;
 	}
 
-	ctx->buf_data = buf_data;
 	if (ret) {
 		io_sqe_buffers_unregister(ctx);
 		return ret;
@@ -9833,6 +9856,55 @@ static struct file *io_uring_get_file(struct io_ring_ctx *ctx)
 	return file;
 }
 
+static int io_attach_buf_data(struct io_ring_ctx *ctx,
+			      struct io_uring_params *p)
+{
+	struct io_ring_ctx *ctx_attach;
+	struct fd f;
+
+	f = fdget(p->wq_fd);
+	if (!f.file)
+		return -EBADF;
+	if (f.file->f_op != &io_uring_fops) {
+		fdput(f);
+		return -EINVAL;
+	}
+
+	ctx_attach = f.file->private_data;
+	if (!ctx_attach->buf_data) {
+		fdput(f);
+		return -EINVAL;
+	}
+	ctx->buf_data = ctx_attach->buf_data;
+
+	percpu_ref_get(&ctx->buf_data->refs);
+	fdput(f);
+	return 0;
+}
+
+static int io_init_buf_data(struct io_ring_ctx *ctx, struct io_uring_params *p)
+{
+	if ((p->flags & (IORING_SETUP_SHARE_BUF | IORING_SETUP_ATTACH_BUF)) ==
+	    (IORING_SETUP_SHARE_BUF | IORING_SETUP_ATTACH_BUF))
+		return -EINVAL;
+
+	if (p->flags & IORING_SETUP_SHARE_BUF) {
+		struct fixed_rsrc_data *buf_data;
+
+		buf_data = alloc_fixed_rsrc_data(ctx);
+		if (IS_ERR(buf_data))
+			return PTR_ERR(buf_data);
+
+		ctx->buf_data = buf_data;
+		return 0;
+	}
+
+	if (p->flags & IORING_SETUP_ATTACH_BUF)
+		return io_attach_buf_data(ctx, p);
+
+	return 0;
+}
+
 static int io_uring_create(unsigned entries, struct io_uring_params *p,
 			   struct io_uring_params __user *params)
 {
@@ -9950,6 +10022,10 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p,
 	if (ret)
 		goto err;
 
+	ret = io_init_buf_data(ctx, p);
+	if (ret)
+		goto err;
+
 	ret = io_sq_offload_create(ctx, p);
 	if (ret)
 		goto err;
@@ -10030,6 +10106,7 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
 	if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
 			IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |
 			IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
+			IORING_SETUP_SHARE_BUF | IORING_SETUP_ATTACH_BUF |
 			IORING_SETUP_R_DISABLED))
 		return -EINVAL;
 
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index b289ef8..3ad786a 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -98,6 +98,8 @@ enum {
 #define IORING_SETUP_CLAMP	(1U << 4)	/* clamp SQ/CQ ring sizes */
 #define IORING_SETUP_ATTACH_WQ	(1U << 5)	/* attach to existing wq */
 #define IORING_SETUP_R_DISABLED	(1U << 6)	/* start with ring disabled */
+#define IORING_SETUP_SHARE_BUF	(1U << 7)	/* share buffer registration */
+#define IORING_SETUP_ATTACH_BUF	(1U << 8)	/* attach buffer registration */
 
 enum {
 	IORING_OP_NOP,
-- 
1.8.3.1

Re: [PATCH v4 00/13] io_uring: buffer registration enhancements

[Jens Axboe]

On 1/6/21 1:39 PM, Bijan Mottahedeh wrote:
> v4:
> 
> - address v3 comments (TBD REGISTER_BUFFERS)
> - rebase
> 
> v3:
> 
> - batch file->rsrc renames into a signle patch when possible
> - fix other review changes from v2
> - fix checkpatch warnings
> 
> v2:
> 
> - drop readv/writev with fixed buffers patch
> - handle ref_nodes both both files/buffers with a single ref_list
> - make file/buffer handling more unified
> 
> This patchset implements a set of enhancements to buffer registration
> consistent with existing file registration functionality:
> 
> - buffer registration updates		IORING_REGISTER_BUFFERS_UPDATE
> 					IORING_OP_BUFFERS_UPDATE
> 
> - buffer registration sharing		IORING_SETUP_SHARE_BUF
> 					IORING_SETUP_ATTACH_BUF
> 
> I have kept the original patchset unchanged for the most part to
> facilitate reviewing and so this set adds a number of additional patches
> mostly making file/buffer handling more unified.
> 
> Patch 1-2 modularize existing buffer registration code.

Applied 1-2 for now with Pavel's review, hopefully we can crank through
the rest of the series and target 5.12.

-- 
Jens Axboe

Re: [PATCH v4 00/13] io_uring: buffer registration enhancements

[Bijan Mottahedeh]

On 1/7/2021 7:53 AM, Jens Axboe wrote:
> On 1/6/21 1:39 PM, Bijan Mottahedeh wrote:
>> v4:
>>
>> - address v3 comments (TBD REGISTER_BUFFERS)
>> - rebase
>>
>> v3:
>>
>> - batch file->rsrc renames into a signle patch when possible
>> - fix other review changes from v2
>> - fix checkpatch warnings
>>
>> v2:
>>
>> - drop readv/writev with fixed buffers patch
>> - handle ref_nodes both both files/buffers with a single ref_list
>> - make file/buffer handling more unified
>>
>> This patchset implements a set of enhancements to buffer registration
>> consistent with existing file registration functionality:
>>
>> - buffer registration updates		IORING_REGISTER_BUFFERS_UPDATE
>> 					IORING_OP_BUFFERS_UPDATE
>>
>> - buffer registration sharing		IORING_SETUP_SHARE_BUF
>> 					IORING_SETUP_ATTACH_BUF
>>
>> I have kept the original patchset unchanged for the most part to
>> facilitate reviewing and so this set adds a number of additional patches
>> mostly making file/buffer handling more unified.
>>
>> Patch 1-2 modularize existing buffer registration code.
> 
> Applied 1-2 for now with Pavel's review, hopefully we can crank through
> the rest of the series and target 5.12.
> 

Thanks.  As for the other patches, #13 needs some attention based on 
Pavel's observations regarding possible deadlocks.  Can you have a look 
at the discussion for that patch in the v2 series?