[PATCH v2 for-next 00/13] resend of for-next cleanups

[PATCH v2 for-next 00/13] resend of for-next cleanups

[Pavel Begunkov]

The series is based on the 5.14 branch with fixes from 5.13 that are
missing applied on top:

216e5835966a io_uring: fix misaccounting fix buf pinned pages
b16ef427adf3 io_uring: fix data race to avoid potential NULL-deref
3743c1723bfc io-wq: Fix UAF when wakeup wqe in hash waitqueue
17a91051fe63 io_uring/io-wq: close io-wq full-stop gap

v2: rebase
    droped one not important patch

Pavel Begunkov (13):
  io-wq: embed wqe ptr array into struct io_wq
  io-wq: remove unused io-wq refcounting
  io_uring: refactor io_iopoll_req_issued
  io_uring: rename function *task_file
  io-wq: don't repeat IO_WQ_BIT_EXIT check by worker
  io-wq: simplify worker exiting
  io_uring: hide rsrc tag copy into generic helpers
  io_uring: remove rsrc put work irq save/restore
  io_uring: add helpers for 2 level table alloc
  io_uring: don't vmalloc rsrc tags
  io_uring: cache task struct refs
  io_uring: unify SQPOLL and user task cancellations
  io_uring: inline io_iter_do_read()

 fs/io-wq.c    |  29 +----
 fs/io_uring.c | 349 ++++++++++++++++++++++++++------------------------
 2 files changed, 191 insertions(+), 187 deletions(-)

-- 
2.31.1

[PATCH 01/13] io-wq: embed wqe ptr array into struct io_wq

[Pavel Begunkov]

io-wq keeps an array of pointers to struct io_wqe, allocate this array
as a part of struct io-wq, it's easier to code and saves an extra
indirection for nearly each io-wq call.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io-wq.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index b3e8624a37d0..1ca98fc7d52b 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -102,7 +102,6 @@ struct io_wqe {
  * Per io_wq state
   */
 struct io_wq {
-	struct io_wqe **wqes;
 	unsigned long state;
 
 	free_work_fn *free_work;
@@ -118,6 +117,8 @@ struct io_wq {
 	struct hlist_node cpuhp_node;
 
 	struct task_struct *task;
+
+	struct io_wqe *wqes[];
 };
 
 static enum cpuhp_state io_wq_online;
@@ -907,17 +908,12 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
 	if (WARN_ON_ONCE(!data->free_work || !data->do_work))
 		return ERR_PTR(-EINVAL);
 
-	wq = kzalloc(sizeof(*wq), GFP_KERNEL);
+	wq = kzalloc(struct_size(wq, wqes, nr_node_ids), GFP_KERNEL);
 	if (!wq)
 		return ERR_PTR(-ENOMEM);
-
-	wq->wqes = kcalloc(nr_node_ids, sizeof(struct io_wqe *), GFP_KERNEL);
-	if (!wq->wqes)
-		goto err_wq;
-
 	ret = cpuhp_state_add_instance_nocalls(io_wq_online, &wq->cpuhp_node);
 	if (ret)
-		goto err_wqes;
+		goto err_wq;
 
 	refcount_inc(&data->hash->refs);
 	wq->hash = data->hash;
@@ -962,8 +958,6 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
 	cpuhp_state_remove_instance_nocalls(io_wq_online, &wq->cpuhp_node);
 	for_each_node(node)
 		kfree(wq->wqes[node]);
-err_wqes:
-	kfree(wq->wqes);
 err_wq:
 	kfree(wq);
 	return ERR_PTR(ret);
@@ -1036,7 +1030,6 @@ static void io_wq_destroy(struct io_wq *wq)
 		kfree(wqe);
 	}
 	io_wq_put_hash(wq->hash);
-	kfree(wq->wqes);
 	kfree(wq);
 }
 
-- 
2.31.1

[PATCH 02/13] io-wq: remove unused io-wq refcounting

[Pavel Begunkov]

iowq->refs is initialised to one and killed on exit, so it's not used
and we can kill it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io-wq.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 1ca98fc7d52b..f058ea0bcae8 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -109,8 +109,6 @@ struct io_wq {
 
 	struct io_wq_hash *hash;
 
-	refcount_t refs;
-
 	atomic_t worker_refs;
 	struct completion worker_done;
 
@@ -949,7 +947,6 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
 	}
 
 	wq->task = get_task_struct(data->task);
-	refcount_set(&wq->refs, 1);
 	atomic_set(&wq->worker_refs, 1);
 	init_completion(&wq->worker_done);
 	return wq;
@@ -1038,8 +1035,7 @@ void io_wq_put_and_exit(struct io_wq *wq)
 	WARN_ON_ONCE(!test_bit(IO_WQ_BIT_EXIT, &wq->state));
 
 	io_wq_exit_workers(wq);
-	if (refcount_dec_and_test(&wq->refs))
-		io_wq_destroy(wq);
+	io_wq_destroy(wq);
 }
 
 static bool io_wq_worker_affinity(struct io_worker *worker, void *data)
-- 
2.31.1

[PATCH 03/13] io_uring: refactor io_iopoll_req_issued

[Pavel Begunkov]

A simple refactoring of io_iopoll_req_issued(), move in_async inside so
we don't pass it around and save on double checking it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 44 +++++++++++++++++++++-----------------------
 1 file changed, 21 insertions(+), 23 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 485f1f055db3..8fbb48c1ac7a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2520,9 +2520,14 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
  * find it from a io_do_iopoll() thread before the issuer is done
  * accessing the kiocb cookie.
  */
-static void io_iopoll_req_issued(struct io_kiocb *req, bool in_async)
+static void io_iopoll_req_issued(struct io_kiocb *req)
 {
 	struct io_ring_ctx *ctx = req->ctx;
+	const bool in_async = io_wq_current_is_worker();
+
+	/* workqueue context doesn't hold uring_lock, grab it now */
+	if (unlikely(in_async))
+		mutex_lock(&ctx->uring_lock);
 
 	/*
 	 * Track whether we have multiple files in our lists. This will impact
@@ -2549,14 +2554,19 @@ static void io_iopoll_req_issued(struct io_kiocb *req, bool in_async)
 	else
 		list_add_tail(&req->inflight_entry, &ctx->iopoll_list);
 
-	/*
-	 * If IORING_SETUP_SQPOLL is enabled, sqes are either handled in sq thread
-	 * task context or in io worker task context. If current task context is
-	 * sq thread, we don't need to check whether should wake up sq thread.
-	 */
-	if (in_async && (ctx->flags & IORING_SETUP_SQPOLL) &&
-	    wq_has_sleeper(&ctx->sq_data->wait))
-		wake_up(&ctx->sq_data->wait);
+	if (unlikely(in_async)) {
+		/*
+		 * If IORING_SETUP_SQPOLL is enabled, sqes are either handle
+		 * in sq thread task context or in io worker task context. If
+		 * current task context is sq thread, we don't need to check
+		 * whether should wake up sq thread.
+		 */
+		if ((ctx->flags & IORING_SETUP_SQPOLL) &&
+		    wq_has_sleeper(&ctx->sq_data->wait))
+			wake_up(&ctx->sq_data->wait);
+
+		mutex_unlock(&ctx->uring_lock);
+	}
 }
 
 static inline void io_state_file_put(struct io_submit_state *state)
@@ -6210,23 +6220,11 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
 
 	if (creds)
 		revert_creds(creds);
-
 	if (ret)
 		return ret;
-
 	/* If the op doesn't have a file, we're not polling for it */
-	if ((ctx->flags & IORING_SETUP_IOPOLL) && req->file) {
-		const bool in_async = io_wq_current_is_worker();
-
-		/* workqueue context doesn't hold uring_lock, grab it now */
-		if (in_async)
-			mutex_lock(&ctx->uring_lock);
-
-		io_iopoll_req_issued(req, in_async);
-
-		if (in_async)
-			mutex_unlock(&ctx->uring_lock);
-	}
+	if ((ctx->flags & IORING_SETUP_IOPOLL) && req->file)
+		io_iopoll_req_issued(req);
 
 	return 0;
 }
-- 
2.31.1

[PATCH 04/13] io_uring: rename function *task_file

[Pavel Begunkov]

What at some moment was references to struct file used to control
lifetimes of task/ctx is now just internal tctx structures/nodes,
so rename outdated *task_file() routines into something more sensible.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8fbb48c1ac7a..cea3d0f5dad5 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1024,7 +1024,7 @@ static const struct io_op_def io_op_defs[] = {
 };
 
 static bool io_disarm_next(struct io_kiocb *req);
-static void io_uring_del_task_file(unsigned long index);
+static void io_uring_del_tctx_node(unsigned long index);
 static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
 					 struct task_struct *task,
 					 bool cancel_all);
@@ -8709,7 +8709,7 @@ static void io_tctx_exit_cb(struct callback_head *cb)
 	 * node. It'll be removed by the end of cancellation, just ignore it.
 	 */
 	if (!atomic_read(&tctx->in_idle))
-		io_uring_del_task_file((unsigned long)work->ctx);
+		io_uring_del_tctx_node((unsigned long)work->ctx);
 	complete(&work->completion);
 }
 
@@ -8962,7 +8962,7 @@ static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
 	}
 }
 
-static int __io_uring_add_task_file(struct io_ring_ctx *ctx)
+static int __io_uring_add_tctx_node(struct io_ring_ctx *ctx)
 {
 	struct io_uring_task *tctx = current->io_uring;
 	struct io_tctx_node *node;
@@ -8999,19 +8999,19 @@ static int __io_uring_add_task_file(struct io_ring_ctx *ctx)
 /*
  * Note that this task has used io_uring. We use it for cancelation purposes.
  */
-static inline int io_uring_add_task_file(struct io_ring_ctx *ctx)
+static inline int io_uring_add_tctx_node(struct io_ring_ctx *ctx)
 {
 	struct io_uring_task *tctx = current->io_uring;
 
 	if (likely(tctx && tctx->last == ctx))
 		return 0;
-	return __io_uring_add_task_file(ctx);
+	return __io_uring_add_tctx_node(ctx);
 }
 
 /*
  * Remove this io_uring_file -> task mapping.
  */
-static void io_uring_del_task_file(unsigned long index)
+static void io_uring_del_tctx_node(unsigned long index)
 {
 	struct io_uring_task *tctx = current->io_uring;
 	struct io_tctx_node *node;
@@ -9041,7 +9041,7 @@ static void io_uring_clean_tctx(struct io_uring_task *tctx)
 	unsigned long index;
 
 	xa_for_each(&tctx->xa, index, node)
-		io_uring_del_task_file(index);
+		io_uring_del_tctx_node(index);
 	if (wq) {
 		/*
 		 * Must be after io_uring_del_task_file() (removes nodes under
@@ -9325,7 +9325,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
 		}
 		submitted = to_submit;
 	} else if (to_submit) {
-		ret = io_uring_add_task_file(ctx);
+		ret = io_uring_add_tctx_node(ctx);
 		if (unlikely(ret))
 			goto out;
 		mutex_lock(&ctx->uring_lock);
@@ -9535,7 +9535,7 @@ static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file)
 	if (fd < 0)
 		return fd;
 
-	ret = io_uring_add_task_file(ctx);
+	ret = io_uring_add_tctx_node(ctx);
 	if (ret) {
 		put_unused_fd(fd);
 		return ret;
-- 
2.31.1

[PATCH 05/13] io-wq: don't repeat IO_WQ_BIT_EXIT check by worker

[Pavel Begunkov]

io_wqe_worker()'s main loop does check IO_WQ_BIT_EXIT flag, so no need
for a second test_bit at the end as it will immediately jump to the
first check afterwards.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io-wq.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index f058ea0bcae8..8c13e23d4a8a 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -559,8 +559,7 @@ static int io_wqe_worker(void *data)
 		if (ret)
 			continue;
 		/* timed out, exit unless we're the fixed worker */
-		if (test_bit(IO_WQ_BIT_EXIT, &wq->state) ||
-		    !(worker->flags & IO_WORKER_F_FIXED))
+		if (!(worker->flags & IO_WORKER_F_FIXED))
 			break;
 	}
 
-- 
2.31.1

[PATCH 06/13] io-wq: simplify worker exiting

[Pavel Begunkov]

io_worker_handle_work() already takes care of the empty list case and
releases spinlock, so get rid of ugly conditional unlocking and
unconditionally call handle_work()

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io-wq.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 8c13e23d4a8a..2c37776c0280 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -565,10 +565,7 @@ static int io_wqe_worker(void *data)
 
 	if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
 		raw_spin_lock_irq(&wqe->lock);
-		if (!wq_list_empty(&wqe->work_list))
-			io_worker_handle_work(worker);
-		else
-			raw_spin_unlock_irq(&wqe->lock);
+		io_worker_handle_work(worker);
 	}
 
 	io_worker_exit(worker);
-- 
2.31.1

[PATCH 07/13] io_uring: hide rsrc tag copy into generic helpers

[Pavel Begunkov]

Make io_rsrc_data_alloc() taking care of rsrc tags loading on
registration, so we don't need to repeat it for each new rsrc type.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 55 +++++++++++++++++++++++++--------------------------
 1 file changed, 27 insertions(+), 28 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index cea3d0f5dad5..18ed6ecb1d76 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7156,27 +7156,38 @@ static void io_rsrc_data_free(struct io_rsrc_data *data)
 	kfree(data);
 }
 
-static struct io_rsrc_data *io_rsrc_data_alloc(struct io_ring_ctx *ctx,
-					       rsrc_put_fn *do_put,
-					       unsigned nr)
+static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, rsrc_put_fn *do_put,
+			      u64 __user *utags, unsigned nr,
+			      struct io_rsrc_data **pdata)
 {
 	struct io_rsrc_data *data;
+	unsigned i;
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
-		return NULL;
+		return -ENOMEM;
 
 	data->tags = kvcalloc(nr, sizeof(*data->tags), GFP_KERNEL);
 	if (!data->tags) {
 		kfree(data);
-		return NULL;
+		return -ENOMEM;
+	}
+	if (utags) {
+		for (i = 0; i < nr; i++) {
+			if (copy_from_user(&data->tags[i], &utags[i],
+					   sizeof(data->tags[i]))) {
+				io_rsrc_data_free(data);
+				return -EFAULT;
+			}
+		}
 	}
 
 	atomic_set(&data->refs, 1);
 	data->ctx = ctx;
 	data->do_put = do_put;
 	init_completion(&data->done);
-	return data;
+	*pdata = data;
+	return 0;
 }
 
 static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
@@ -7628,7 +7639,6 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 	struct file *file;
 	int fd, ret;
 	unsigned i;
-	struct io_rsrc_data *file_data;
 
 	if (ctx->file_data)
 		return -EBUSY;
@@ -7639,27 +7649,24 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 	ret = io_rsrc_node_switch_start(ctx);
 	if (ret)
 		return ret;
+	ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args,
+				 &ctx->file_data);
+	if (ret)
+		return ret;
 
-	file_data = io_rsrc_data_alloc(ctx, io_rsrc_file_put, nr_args);
-	if (!file_data)
-		return -ENOMEM;
-	ctx->file_data = file_data;
 	ret = -ENOMEM;
 	if (!io_alloc_file_tables(&ctx->file_table, nr_args))
 		goto out_free;
 
 	for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
-		u64 tag = 0;
-
-		if ((tags && copy_from_user(&tag, &tags[i], sizeof(tag))) ||
-		    copy_from_user(&fd, &fds[i], sizeof(fd))) {
+		if (copy_from_user(&fd, &fds[i], sizeof(fd))) {
 			ret = -EFAULT;
 			goto out_fput;
 		}
 		/* allow sparse sets */
 		if (fd == -1) {
 			ret = -EINVAL;
-			if (unlikely(tag))
+			if (unlikely(ctx->file_data->tags[i]))
 				goto out_fput;
 			continue;
 		}
@@ -7680,7 +7687,6 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 			fput(file);
 			goto out_fput;
 		}
-		ctx->file_data->tags[i] = tag;
 		io_fixed_file_set(io_fixed_file_slot(&ctx->file_table, i), file);
 	}
 
@@ -8398,9 +8404,9 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 	ret = io_rsrc_node_switch_start(ctx);
 	if (ret)
 		return ret;
-	data = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, nr_args);
-	if (!data)
-		return -ENOMEM;
+	ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data);
+	if (ret)
+		return ret;
 	ret = io_buffers_map_alloc(ctx, nr_args);
 	if (ret) {
 		io_rsrc_data_free(data);
@@ -8408,19 +8414,13 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 	}
 
 	for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
-		u64 tag = 0;
-
-		if (tags && copy_from_user(&tag, &tags[i], sizeof(tag))) {
-			ret = -EFAULT;
-			break;
-		}
 		ret = io_copy_iov(ctx, &iov, arg, i);
 		if (ret)
 			break;
 		ret = io_buffer_validate(&iov);
 		if (ret)
 			break;
-		if (!iov.iov_base && tag) {
+		if (!iov.iov_base && data->tags[i]) {
 			ret = -EINVAL;
 			break;
 		}
@@ -8429,7 +8429,6 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 					     &last_hpage);
 		if (ret)
 			break;
-		data->tags[i] = tag;
 	}
 
 	WARN_ON_ONCE(ctx->buf_data);
-- 
2.31.1

[PATCH 08/13] io_uring: remove rsrc put work irq save/restore

[Pavel Begunkov]

io_rsrc_put_work() is executed by workqueue in non-irq context, so no
need for irqsave/restore variants of spinlocking.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 18ed6ecb1d76..59cd9dc6164c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7550,14 +7550,13 @@ static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
 
 		if (prsrc->tag) {
 			bool lock_ring = ctx->flags & IORING_SETUP_IOPOLL;
-			unsigned long flags;
 
 			io_ring_submit_lock(ctx, lock_ring);
-			spin_lock_irqsave(&ctx->completion_lock, flags);
+			spin_lock_irq(&ctx->completion_lock);
 			io_cqring_fill_event(ctx, prsrc->tag, 0, 0);
 			ctx->cq_extra++;
 			io_commit_cqring(ctx);
-			spin_unlock_irqrestore(&ctx->completion_lock, flags);
+			spin_unlock_irq(&ctx->completion_lock);
 			io_cqring_ev_posted(ctx);
 			io_ring_submit_unlock(ctx, lock_ring);
 		}
-- 
2.31.1

[PATCH 09/13] io_uring: add helpers for 2 level table alloc

[Pavel Begunkov]

Some parts like fixed file table use 2 level tables, factor out helpers
for allocating/deallocating them as more users are to come.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 73 ++++++++++++++++++++++++++++++---------------------
 1 file changed, 43 insertions(+), 30 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 59cd9dc6164c..d6c1322119d6 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7054,14 +7054,36 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 	return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
 }
 
-static void io_free_file_tables(struct io_file_table *table, unsigned nr_files)
+static void io_free_page_table(void **table, size_t size)
 {
-	unsigned i, nr_tables = DIV_ROUND_UP(nr_files, IORING_MAX_FILES_TABLE);
+	unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
 
 	for (i = 0; i < nr_tables; i++)
-		kfree(table->files[i]);
-	kfree(table->files);
-	table->files = NULL;
+		kfree(table[i]);
+	kfree(table);
+}
+
+static void **io_alloc_page_table(size_t size)
+{
+	unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
+	size_t init_size = size;
+	void **table;
+
+	table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL);
+	if (!table)
+		return NULL;
+
+	for (i = 0; i < nr_tables; i++) {
+		unsigned int this_size = min(size, PAGE_SIZE);
+
+		table[i] = kzalloc(this_size, GFP_KERNEL);
+		if (!table[i]) {
+			io_free_page_table(table, init_size);
+			return NULL;
+		}
+		size -= this_size;
+	}
+	return table;
 }
 
 static inline void io_rsrc_ref_lock(struct io_ring_ctx *ctx)
@@ -7190,6 +7212,22 @@ static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, rsrc_put_fn *do_put,
 	return 0;
 }
 
+static bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files)
+{
+	size_t size = nr_files * sizeof(struct io_fixed_file);
+
+	table->files = (struct io_fixed_file **)io_alloc_page_table(size);
+	return !!table->files;
+}
+
+static void io_free_file_tables(struct io_file_table *table, unsigned nr_files)
+{
+	size_t size = nr_files * sizeof(struct io_fixed_file);
+
+	io_free_page_table((void **)table->files, size);
+	table->files = NULL;
+}
+
 static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
 {
 #if defined(CONFIG_UNIX)
@@ -7451,31 +7489,6 @@ static int io_sqe_files_scm(struct io_ring_ctx *ctx)
 }
 #endif
 
-static bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files)
-{
-	unsigned i, nr_tables = DIV_ROUND_UP(nr_files, IORING_MAX_FILES_TABLE);
-
-	table->files = kcalloc(nr_tables, sizeof(*table->files), GFP_KERNEL);
-	if (!table->files)
-		return false;
-
-	for (i = 0; i < nr_tables; i++) {
-		unsigned int this_files = min(nr_files, IORING_MAX_FILES_TABLE);
-
-		table->files[i] = kcalloc(this_files, sizeof(*table->files[i]),
-					GFP_KERNEL);
-		if (!table->files[i])
-			break;
-		nr_files -= this_files;
-	}
-
-	if (i == nr_tables)
-		return true;
-
-	io_free_file_tables(table, nr_tables * IORING_MAX_FILES_TABLE);
-	return false;
-}
-
 static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
 {
 	struct file *file = prsrc->file;
-- 
2.31.1

[PATCH 10/13] io_uring: don't vmalloc rsrc tags

[Pavel Begunkov]

We don't really need vmalloc for keeping tags, it's not a hot path and
is there out of convenience, so replace it with two level tables to not
litter kernel virtual memory mappings.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 52 +++++++++++++++++++++++++++++++++++----------------
 1 file changed, 36 insertions(+), 16 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index d6c1322119d6..692c91d03054 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -100,6 +100,10 @@
 #define IORING_MAX_RESTRICTIONS	(IORING_RESTRICTION_LAST + \
 				 IORING_REGISTER_LAST + IORING_OP_LAST)
 
+#define IO_RSRC_TAG_TABLE_SHIFT	9
+#define IO_RSRC_TAG_TABLE_MAX	(1U << IO_RSRC_TAG_TABLE_SHIFT)
+#define IO_RSRC_TAG_TABLE_MASK	(IO_RSRC_TAG_TABLE_MAX - 1)
+
 #define IORING_MAX_REG_BUFFERS	(1U << 14)
 
 #define SQE_VALID_FLAGS	(IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK|	\
@@ -243,7 +247,8 @@ typedef void (rsrc_put_fn)(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
 struct io_rsrc_data {
 	struct io_ring_ctx		*ctx;
 
-	u64				*tags;
+	u64				**tags;
+	unsigned int			nr;
 	rsrc_put_fn			*do_put;
 	atomic_t			refs;
 	struct completion		done;
@@ -7172,9 +7177,20 @@ static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, struct io_ring_ctx *ct
 	return ret;
 }
 
+static u64 *io_get_tag_slot(struct io_rsrc_data *data, unsigned int idx)
+{
+	unsigned int off = idx & IO_RSRC_TAG_TABLE_MASK;
+	unsigned int table_idx = idx >> IO_RSRC_TAG_TABLE_SHIFT;
+
+	return &data->tags[table_idx][off];
+}
+
 static void io_rsrc_data_free(struct io_rsrc_data *data)
 {
-	kvfree(data->tags);
+	size_t size = data->nr * sizeof(data->tags[0][0]);
+
+	if (data->tags)
+		io_free_page_table((void **)data->tags, size);
 	kfree(data);
 }
 
@@ -7183,33 +7199,37 @@ static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, rsrc_put_fn *do_put,
 			      struct io_rsrc_data **pdata)
 {
 	struct io_rsrc_data *data;
+	int ret = -ENOMEM;
 	unsigned i;
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
-
-	data->tags = kvcalloc(nr, sizeof(*data->tags), GFP_KERNEL);
+	data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
 	if (!data->tags) {
 		kfree(data);
 		return -ENOMEM;
 	}
+
+	data->nr = nr;
+	data->ctx = ctx;
+	data->do_put = do_put;
 	if (utags) {
+		ret = -EFAULT;
 		for (i = 0; i < nr; i++) {
-			if (copy_from_user(&data->tags[i], &utags[i],
-					   sizeof(data->tags[i]))) {
-				io_rsrc_data_free(data);
-				return -EFAULT;
-			}
+			if (copy_from_user(io_get_tag_slot(data, i), &utags[i],
+					   sizeof(data->tags[i])))
+				goto fail;
 		}
 	}
 
 	atomic_set(&data->refs, 1);
-	data->ctx = ctx;
-	data->do_put = do_put;
 	init_completion(&data->done);
 	*pdata = data;
 	return 0;
+fail:
+	io_rsrc_data_free(data);
+	return ret;
 }
 
 static bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files)
@@ -7678,7 +7698,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 		/* allow sparse sets */
 		if (fd == -1) {
 			ret = -EINVAL;
-			if (unlikely(ctx->file_data->tags[i]))
+			if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
 				goto out_fput;
 			continue;
 		}
@@ -7776,7 +7796,7 @@ static int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
 	if (!prsrc)
 		return -ENOMEM;
 
-	prsrc->tag = data->tags[idx];
+	prsrc->tag = *io_get_tag_slot(data, idx);
 	prsrc->rsrc = rsrc;
 	list_add(&prsrc->list, &node->rsrc_list);
 	return 0;
@@ -7846,7 +7866,7 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 				err = -EBADF;
 				break;
 			}
-			data->tags[up->offset + done] = tag;
+			*io_get_tag_slot(data, up->offset + done) = tag;
 			io_fixed_file_set(file_slot, file);
 			err = io_sqe_file_register(ctx, file, i);
 			if (err) {
@@ -8432,7 +8452,7 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 		ret = io_buffer_validate(&iov);
 		if (ret)
 			break;
-		if (!iov.iov_base && data->tags[i]) {
+		if (!iov.iov_base && *io_get_tag_slot(data, i)) {
 			ret = -EINVAL;
 			break;
 		}
@@ -8505,7 +8525,7 @@ static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
 		}
 
 		ctx->user_bufs[i] = imu;
-		ctx->buf_data->tags[offset] = tag;
+		*io_get_tag_slot(ctx->buf_data, offset) = tag;
 	}
 
 	if (needs_switch)
-- 
2.31.1

[PATCH 11/13] io_uring: cache task struct refs

[Pavel Begunkov]

tctx in submission part is always synchronised because is executed from
the task's context, so we can batch allocate tctx/task references and
store them across syscall boundaries. It avoids enough of operations,
including an atomic for getting task ref and a percpu_counter_add()
function call, which still fallback to spinlock for large batching
cases (around >=32). Should be good for SQPOLL submitting in small
portions and coming at some moment bpf submissions.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 692c91d03054..23b15ed98815 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -110,6 +110,8 @@
 				IOSQE_IO_HARDLINK | IOSQE_ASYNC | \
 				IOSQE_BUFFER_SELECT)
 
+#define IO_TCTX_REFS_CACHE_NR	(1U << 10)
+
 struct io_uring {
 	u32 head ____cacheline_aligned_in_smp;
 	u32 tail ____cacheline_aligned_in_smp;
@@ -472,6 +474,7 @@ struct io_ring_ctx {
 
 struct io_uring_task {
 	/* submission side */
+	int			cached_refs;
 	struct xarray		xa;
 	struct wait_queue_head	wait;
 	const struct io_ring_ctx *last;
@@ -6702,16 +6705,23 @@ static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx)
 
 static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
 {
+	struct io_uring_task *tctx;
 	int submitted = 0;
 
 	/* make sure SQ entry isn't read before tail */
 	nr = min3(nr, ctx->sq_entries, io_sqring_entries(ctx));
-
 	if (!percpu_ref_tryget_many(&ctx->refs, nr))
 		return -EAGAIN;
 
-	percpu_counter_add(&current->io_uring->inflight, nr);
-	refcount_add(nr, &current->usage);
+	tctx = current->io_uring;
+	tctx->cached_refs -= nr;
+	if (unlikely(tctx->cached_refs < 0)) {
+		unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR;
+
+		percpu_counter_add(&tctx->inflight, refill);
+		refcount_add(refill, &current->usage);
+		tctx->cached_refs += refill;
+	}
 	io_submit_state_start(&ctx->submit_state, nr);
 
 	while (submitted < nr) {
@@ -6737,12 +6747,10 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
 
 	if (unlikely(submitted != nr)) {
 		int ref_used = (submitted == -EAGAIN) ? 0 : submitted;
-		struct io_uring_task *tctx = current->io_uring;
 		int unused = nr - ref_used;
 
+		current->io_uring->cached_refs += unused;
 		percpu_ref_put_many(&ctx->refs, unused);
-		percpu_counter_sub(&tctx->inflight, unused);
-		put_task_struct_many(current, unused);
 	}
 
 	io_submit_state_end(&ctx->submit_state, ctx);
@@ -7924,7 +7932,7 @@ static int io_uring_alloc_task_context(struct task_struct *task,
 	struct io_uring_task *tctx;
 	int ret;
 
-	tctx = kmalloc(sizeof(*tctx), GFP_KERNEL);
+	tctx = kzalloc(sizeof(*tctx), GFP_KERNEL);
 	if (unlikely(!tctx))
 		return -ENOMEM;
 
@@ -7944,13 +7952,11 @@ static int io_uring_alloc_task_context(struct task_struct *task,
 
 	xa_init(&tctx->xa);
 	init_waitqueue_head(&tctx->wait);
-	tctx->last = NULL;
 	atomic_set(&tctx->in_idle, 0);
 	atomic_set(&tctx->inflight_tracked, 0);
 	task->io_uring = tctx;
 	spin_lock_init(&tctx->task_lock);
 	INIT_WQ_LIST(&tctx->task_list);
-	tctx->task_state = 0;
 	init_task_work(&tctx->task_work, tctx_task_work);
 	return 0;
 }
@@ -7961,6 +7967,7 @@ void __io_uring_free(struct task_struct *tsk)
 
 	WARN_ON_ONCE(!xa_empty(&tctx->xa));
 	WARN_ON_ONCE(tctx->io_wq);
+	WARN_ON_ONCE(tctx->cached_refs);
 
 	percpu_counter_destroy(&tctx->inflight);
 	kfree(tctx);
@@ -9105,6 +9112,16 @@ static void io_uring_try_cancel(bool cancel_all)
 	}
 }
 
+static void io_uring_drop_tctx_refs(struct task_struct *task)
+{
+	struct io_uring_task *tctx = task->io_uring;
+	unsigned int refs = tctx->cached_refs;
+
+	tctx->cached_refs = 0;
+	percpu_counter_sub(&tctx->inflight, refs);
+	put_task_struct_many(task, refs);
+}
+
 /* should only be called by SQPOLL task */
 static void io_uring_cancel_sqpoll(struct io_sq_data *sqd)
 {
@@ -9120,6 +9137,7 @@ static void io_uring_cancel_sqpoll(struct io_sq_data *sqd)
 
 	WARN_ON_ONCE(!sqd || sqd->thread != current);
 
+	io_uring_drop_tctx_refs(current);
 	atomic_inc(&tctx->in_idle);
 	do {
 		/* read completions before cancelations */
@@ -9157,6 +9175,7 @@ void __io_uring_cancel(struct files_struct *files)
 		io_wq_exit_start(tctx->io_wq);
 
 	/* make sure overflow events are dropped */
+	io_uring_drop_tctx_refs(current);
 	atomic_inc(&tctx->in_idle);
 	do {
 		/* read completions before cancelations */
-- 
2.31.1

[PATCH 12/13] io_uring: unify SQPOLL and user task cancellations

[Pavel Begunkov]

Merge io_uring_cancel_sqpoll() and __io_uring_cancel() as it's easier to
have a conditional ctx traverse inside than keeping them in sync.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 89 +++++++++++++++++----------------------------------
 1 file changed, 30 insertions(+), 59 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 23b15ed98815..23644179edd4 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1036,7 +1036,7 @@ static void io_uring_del_tctx_node(unsigned long index);
 static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
 					 struct task_struct *task,
 					 bool cancel_all);
-static void io_uring_cancel_sqpoll(struct io_sq_data *sqd);
+static void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
 static struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx);
 
 static bool io_cqring_fill_event(struct io_ring_ctx *ctx, u64 user_data,
@@ -6921,7 +6921,7 @@ static int io_sq_thread(void *data)
 		timeout = jiffies + sqd->sq_thread_idle;
 	}
 
-	io_uring_cancel_sqpoll(sqd);
+	io_uring_cancel_generic(true, sqd);
 	sqd->thread = NULL;
 	list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
 		io_ring_set_wakeup_flag(ctx);
@@ -9097,21 +9097,6 @@ static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)
 	return percpu_counter_sum(&tctx->inflight);
 }
 
-static void io_uring_try_cancel(bool cancel_all)
-{
-	struct io_uring_task *tctx = current->io_uring;
-	struct io_tctx_node *node;
-	unsigned long index;
-
-	xa_for_each(&tctx->xa, index, node) {
-		struct io_ring_ctx *ctx = node->ctx;
-
-		/* sqpoll task will cancel all its requests */
-		if (!ctx->sq_data)
-			io_uring_try_cancel_requests(ctx, current, cancel_all);
-	}
-}
-
 static void io_uring_drop_tctx_refs(struct task_struct *task)
 {
 	struct io_uring_task *tctx = task->io_uring;
@@ -9122,69 +9107,50 @@ static void io_uring_drop_tctx_refs(struct task_struct *task)
 	put_task_struct_many(task, refs);
 }
 
-/* should only be called by SQPOLL task */
-static void io_uring_cancel_sqpoll(struct io_sq_data *sqd)
+/*
+ * Find any io_uring ctx that this task has registered or done IO on, and cancel
+ * requests. @sqd should be not-null IIF it's an SQPOLL thread cancellation.
+ */
+static void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd)
 {
 	struct io_uring_task *tctx = current->io_uring;
 	struct io_ring_ctx *ctx;
 	s64 inflight;
 	DEFINE_WAIT(wait);
 
+	WARN_ON_ONCE(sqd && sqd->thread != current);
+
 	if (!current->io_uring)
 		return;
 	if (tctx->io_wq)
 		io_wq_exit_start(tctx->io_wq);
 
-	WARN_ON_ONCE(!sqd || sqd->thread != current);
-
 	io_uring_drop_tctx_refs(current);
 	atomic_inc(&tctx->in_idle);
 	do {
 		/* read completions before cancelations */
-		inflight = tctx_inflight(tctx, false);
+		inflight = tctx_inflight(tctx, !cancel_all);
 		if (!inflight)
 			break;
-		list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
-			io_uring_try_cancel_requests(ctx, current, true);
 
-		prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE);
-		/*
-		 * If we've seen completions, retry without waiting. This
-		 * avoids a race where a completion comes in before we did
-		 * prepare_to_wait().
-		 */
-		if (inflight == tctx_inflight(tctx, false))
-			schedule();
-		finish_wait(&tctx->wait, &wait);
-	} while (1);
-	atomic_dec(&tctx->in_idle);
-}
+		if (!sqd) {
+			struct io_tctx_node *node;
+			unsigned long index;
 
-/*
- * Find any io_uring fd that this task has registered or done IO on, and cancel
- * requests.
- */
-void __io_uring_cancel(struct files_struct *files)
-{
-	struct io_uring_task *tctx = current->io_uring;
-	DEFINE_WAIT(wait);
-	s64 inflight;
-	bool cancel_all = !files;
-
-	if (tctx->io_wq)
-		io_wq_exit_start(tctx->io_wq);
+			xa_for_each(&tctx->xa, index, node) {
+				/* sqpoll task will cancel all its requests */
+				if (node->ctx->sq_data)
+					continue;
+				io_uring_try_cancel_requests(node->ctx, current,
+							     cancel_all);
+			}
+		} else {
+			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
+				io_uring_try_cancel_requests(ctx, current,
+							     cancel_all);
+		}
 
-	/* make sure overflow events are dropped */
-	io_uring_drop_tctx_refs(current);
-	atomic_inc(&tctx->in_idle);
-	do {
-		/* read completions before cancelations */
-		inflight = tctx_inflight(tctx, !cancel_all);
-		if (!inflight)
-			break;
-		io_uring_try_cancel(cancel_all);
 		prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE);
-
 		/*
 		 * If we've seen completions, retry without waiting. This
 		 * avoids a race where a completion comes in before we did
@@ -9203,6 +9169,11 @@ void __io_uring_cancel(struct files_struct *files)
 	}
 }
 
+void __io_uring_cancel(struct files_struct *files)
+{
+	io_uring_cancel_generic(!files, NULL);
+}
+
 static void *io_uring_validate_mmap_request(struct file *file,
 					    loff_t pgoff, size_t sz)
 {
-- 
2.31.1

[PATCH 13/13] io_uring: inline io_iter_do_read()

[Pavel Begunkov]

There are only two calls in source code of io_iter_do_read(), the
function is small and pretty hot though is failed to get inlined.
Makr it as inline.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 23644179edd4..9c6e1d7dd5b1 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3248,7 +3248,7 @@ static bool io_rw_should_retry(struct io_kiocb *req)
 	return true;
 }
 
-static int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter)
+static inline int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter)
 {
 	if (req->file->f_op->read_iter)
 		return call_read_iter(req->file, &req->rw.kiocb, iter);
-- 
2.31.1

Re: [PATCH v2 for-next 00/13] resend of for-next cleanups

[Jens Axboe]

On 6/13/21 7:36 PM, Pavel Begunkov wrote:
> The series is based on the 5.14 branch with fixes from 5.13 that are
> missing applied on top:
> 
> 216e5835966a io_uring: fix misaccounting fix buf pinned pages
> b16ef427adf3 io_uring: fix data race to avoid potential NULL-deref
> 3743c1723bfc io-wq: Fix UAF when wakeup wqe in hash waitqueue
> 17a91051fe63 io_uring/io-wq: close io-wq full-stop gap

With the API change, I rebased the 5.14 branch and applied this on
top.

-- 
Jens Axboe