From: Bijan Mottahedeh <[email protected]>
To: [email protected]
Cc: [email protected]
Subject: [PATCH 4/8] io_uring: implement fixed buffers registration similar to fixed files
Date: Thu, 12 Nov 2020 15:00:38 -0800 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
Apply fixed_rsrc functionality for fixed buffers support.
Signed-off-by: Bijan Mottahedeh <[email protected]>
---
fs/io_uring.c | 294 +++++++++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 258 insertions(+), 36 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 974a619..de0019e 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;
@@ -338,8 +346,8 @@ 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;
@@ -401,6 +409,9 @@ struct io_ring_ctx {
struct delayed_work file_put_work;
struct llist_head file_put_llist;
+ struct delayed_work buf_put_work;
+ struct llist_head buf_put_llist;
+
struct work_struct exit_work;
struct io_restriction restrictions;
};
@@ -1019,6 +1030,7 @@ 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_buf_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,
@@ -1318,6 +1330,8 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
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->buf_put_work, io_buf_put_work);
+ init_llist_head(&ctx->buf_put_llist);
return ctx;
err:
if (ctx->fallback_req)
@@ -2949,6 +2963,15 @@ 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)
{
@@ -2959,10 +2982,15 @@ static ssize_t io_import_fixed(struct io_kiocb *req, int rw,
size_t offset;
u64 buf_addr;
+ /* attempt to use fixed buffers without having provided iovecs */
+ if (unlikely(!ctx->buf_data))
+ return -EFAULT;
+
+ buf_index = req->buf_index;
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 */
@@ -8167,28 +8195,73 @@ 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 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 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 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;
+
+ spin_lock(&data->lock);
+ if (!list_empty(&data->ref_list))
+ ref_node = list_first_entry(&data->ref_list,
+ struct fixed_rsrc_ref_node, node);
+ spin_unlock(&data->lock);
+ 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->buf_put_work);
+ wait_for_completion(&data->done);
+
+ io_buffers_unmap(ctx);
+ io_buffers_map_free(ctx);
+
return 0;
}
@@ -8241,7 +8314,13 @@ 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 fixed_rsrc_table *table;
+ struct io_mapped_ubuf *imu;
+ unsigned index;
+
+ table = &ctx->buf_data->table[i >> IORING_BUF_TABLE_SHIFT];
+ index = i & IORING_BUF_TABLE_MASK;
+ imu = &table->bufs[index];
for (j = 0; j < imu->nr_bvecs; j++) {
if (!PageCompound(imu->bvec[j].bv_page))
@@ -8376,19 +8455,82 @@ 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 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];
+ kfree(table->bufs);
+ }
+}
- return 0;
+static int io_alloc_buf_tables(struct fixed_rsrc_data *buf_data,
+ unsigned nr_tables, unsigned nr_bufs)
+{
+ int i;
+
+ for (i = 0; i < nr_tables; i++) {
+ struct fixed_rsrc_table *table = &buf_data->table[i];
+ unsigned 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, nr_tables);
+ return 1;
+}
+
+static struct fixed_rsrc_data *io_buffers_map_alloc(struct io_ring_ctx *ctx,
+ unsigned int nr_args)
+{
+ unsigned nr_tables;
+ struct fixed_rsrc_data *buf_data;
+ int ret = -ENOMEM;
+
+ if (ctx->buf_data)
+ return ERR_PTR(-EBUSY);
+ 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);
+ INIT_LIST_HEAD(&buf_data->ref_list);
+ spin_lock_init(&buf_data->lock);
+
+ 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)
@@ -8408,39 +8550,119 @@ static int io_buffer_validate(struct iovec *iov)
return 0;
}
+static void io_buf_put_work(struct work_struct *work)
+{
+ struct io_ring_ctx *ctx;
+ struct llist_node *node;
+
+ ctx = container_of(work, struct io_ring_ctx, buf_put_work.work);
+ node = llist_del_all(&ctx->buf_put_llist);
+ io_rsrc_put_work(node);
+}
+
+static void io_buf_data_ref_zero(struct percpu_ref *ref)
+{
+ struct fixed_rsrc_ref_node *ref_node;
+ struct io_ring_ctx *ctx;
+ bool first_add;
+ int delay = HZ;
+
+ ref_node = container_of(ref, struct fixed_rsrc_ref_node, refs);
+ ctx = ref_node->rsrc_data->ctx;
+
+ if (percpu_ref_is_dying(&ctx->buf_data->refs))
+ delay = 0;
+
+ first_add = llist_add(&ref_node->llist, &ctx->buf_put_llist);
+ if (!delay)
+ mod_delayed_work(system_wq, &ctx->buf_put_work, 0);
+ else if (first_add)
+ queue_delayed_work(system_wq, &ctx->buf_put_work, delay);
+}
+
+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 = kzalloc(sizeof(*ref_node), GFP_KERNEL);
+ if (!ref_node)
+ return ERR_PTR(-ENOMEM);
+
+ if (percpu_ref_init(&ref_node->refs, io_buf_data_ref_zero,
+ 0, GFP_KERNEL)) {
+ kfree(ref_node);
+ return ERR_PTR(-ENOMEM);
+ }
+ INIT_LIST_HEAD(&ref_node->node);
+ INIT_LIST_HEAD(&ref_node->rsrc_list);
+ 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;
+ 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++) {
- struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
+ for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
+ struct fixed_rsrc_table *table;
+ struct io_mapped_ubuf *imu;
+ unsigned index;
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;
+ table = &buf_data->table[i >> IORING_BUF_TABLE_SHIFT];
+ index = i & IORING_BUF_TABLE_MASK;
+ imu = &table->bufs[index];
+
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;
+ spin_lock(&buf_data->lock);
+ list_add(&ref_node->node, &buf_data->ref_list);
+ spin_unlock(&buf_data->lock);
+ percpu_ref_get(&buf_data->refs);
+ return 0;
}
static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
@@ -9217,7 +9439,7 @@ 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);
--
1.8.3.1
next prev parent reply other threads:[~2020-11-12 23:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 23:00 [PATCH 0/8] io_uring: buffer registration enhancements Bijan Mottahedeh
2020-11-12 23:00 ` [PATCH 1/8] io_uring: modularize io_sqe_buffer_register Bijan Mottahedeh
2020-11-12 23:00 ` [PATCH 2/8] io_uring: modularize io_sqe_buffers_register Bijan Mottahedeh
2020-11-12 23:00 ` [PATCH 3/8] io_uring: generalize fixed file functionality Bijan Mottahedeh
2020-11-12 23:00 ` Bijan Mottahedeh [this message]
2020-11-15 13:33 ` [PATCH 4/8] io_uring: implement fixed buffers registration similar to fixed files Pavel Begunkov
2020-11-16 21:24 ` Bijan Mottahedeh
2020-11-16 23:09 ` Pavel Begunkov
2020-11-17 0:41 ` Bijan Mottahedeh
2020-11-12 23:00 ` [PATCH 5/8] io_uring: generalize files_update functionlity to rsrc_update Bijan Mottahedeh
2020-11-12 23:00 ` [PATCH 6/8] io_uring: support buffer registration updates Bijan Mottahedeh
2020-11-18 20:17 ` Pavel Begunkov
2020-12-09 0:42 ` Bijan Mottahedeh
2020-11-12 23:00 ` [PATCH 7/8] io_uring: support readv/writev with fixed buffers Bijan Mottahedeh
2020-11-17 11:04 ` Pavel Begunkov
2020-11-17 22:59 ` Bijan Mottahedeh
2020-11-18 9:14 ` Pavel Begunkov
2020-11-18 20:12 ` Pavel Begunkov
[not found] ` <[email protected]>
[not found] ` <[email protected]>
2020-11-19 19:27 ` Bijan Mottahedeh
2020-11-12 23:00 ` [PATCH 8/8] io_uring: support buffer registration sharing Bijan Mottahedeh
2020-11-16 23:28 ` [PATCH 0/8] io_uring: buffer registration enhancements Pavel Begunkov
2020-11-17 0:21 ` Bijan Mottahedeh
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