6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jens Axboe axboe@kernel.dk
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 --- io_uring/kbuf.c | 15 +++++++++++---- io_uring/kbuf.h | 2 ++ 2 files changed, 13 insertions(+), 4 deletions(-)
--- a/io_uring/kbuf.c +++ b/io_uring/kbuf.c @@ -59,6 +59,7 @@ static int io_buffer_add_list(struct io_ * 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)); }
@@ -272,6 +273,14 @@ static int __io_remove_buffers(struct io 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; @@ -279,8 +288,7 @@ void io_destroy_buffers(struct io_ring_c
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); }
while (!list_empty(&ctx->io_buffers_pages)) { @@ -676,9 +684,8 @@ int io_unregister_pbuf_ring(struct io_ri 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; }
--- 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 */