diff options
| author | Jens Axboe <axboe@kernel.dk> | 2024-03-15 16:12:51 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-04-02 19:03:26 -0600 |
| commit | 6b69c4ab4f685327d9e10caf0d84217ba23a8c4b (patch) | |
| tree | 23d7e9bba95a9bf4af42b3f46d1e428fb470b7e5 | |
| parent | 3b80cff5a4d117c53d38ce805823084eaeffbde6 (diff) | |
io_uring/kbuf: protect io_buffer_list teardown with a reference
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>
| -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 011280d873e7..2edc6854f6f3 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)); } @@ -265,6 +266,14 @@ 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; @@ -274,8 +283,7 @@ 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); } /* @@ -680,9 +688,8 @@ int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) if (!bl->is_buf_ring) 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 fdbb10449513..8b868a1744e2 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_buf_ring; /* ring mapped provided buffers, but mmap'ed by application */ |