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| author | Jens Axboe <axboe@kernel.dk> | 2024-03-16 01:12:51 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-10 17:38:16 +0300 |
| commit | da64e0edbb1bd6524b5287be834f31e074409986 (patch) | |
| tree | e8f61cafd09279b6cb915e6d580b931b734031e7 /io_uring | |
| parent | 4ce585360581eef99dc0ad1717b740b250145b0b (diff) | |
| download | linux-da64e0edbb1bd6524b5287be834f31e074409986.tar.xz | |
io_uring/kbuf: protect io_buffer_list teardown with a reference
commit 6b69c4ab4f685327d9e10caf0d84217ba23a8c4b upstream.
No functional changes in this patch, just in preparation for being able
to keep the buffer list alive outside of the ctx->uring_lock.
Cc: stable@vger.kernel.org # v6.4+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/kbuf.c | 15 | ||||
| -rw-r--r-- | io_uring/kbuf.h | 2 |
2 files changed, 13 insertions, 4 deletions
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c index d5efc7c275c2..f7114e808827 100644 --- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -61,6 +61,7 @@ static int io_buffer_add_list(struct io_ring_ctx *ctx, * always under the ->uring_lock, but the RCU lookup from mmap does. */ bl->bgid = bgid; + atomic_set(&bl->refs, 1); return xa_err(xa_store(&ctx->io_bl_xa, bgid, bl, GFP_KERNEL)); } @@ -274,6 +275,14 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx, return i; } +static void io_put_bl(struct io_ring_ctx *ctx, struct io_buffer_list *bl) +{ + if (atomic_dec_and_test(&bl->refs)) { + __io_remove_buffers(ctx, bl, -1U); + kfree_rcu(bl, rcu); + } +} + void io_destroy_buffers(struct io_ring_ctx *ctx) { struct io_buffer_list *bl; @@ -283,8 +292,7 @@ void io_destroy_buffers(struct io_ring_ctx *ctx) xa_for_each(&ctx->io_bl_xa, index, bl) { xa_erase(&ctx->io_bl_xa, bl->bgid); - __io_remove_buffers(ctx, bl, -1U); - kfree_rcu(bl, rcu); + io_put_bl(ctx, bl); } /* @@ -689,9 +697,8 @@ int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) if (!bl->is_mapped) return -EINVAL; - __io_remove_buffers(ctx, bl, -1U); xa_erase(&ctx->io_bl_xa, bl->bgid); - kfree_rcu(bl, rcu); + io_put_bl(ctx, bl); return 0; } diff --git a/io_uring/kbuf.h b/io_uring/kbuf.h index 3722e44daf0b..55e1c888c3f9 100644 --- a/io_uring/kbuf.h +++ b/io_uring/kbuf.h @@ -25,6 +25,8 @@ struct io_buffer_list { __u16 head; __u16 mask; + atomic_t refs; + /* ring mapped provided buffers */ __u8 is_mapped; /* ring mapped provided buffers, but mmap'ed by application */ |