io_uring: don't free request to slab

It's not necessary to free the request back to slab when we fail to
get sqe, just move it to state->free_list.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20210825175856.194299-1-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e321cb0..be3c3ae 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6889,7 +6889,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
                }
                sqe = io_get_sqe(ctx);
                if (unlikely(!sqe)) {
-                       kmem_cache_free(req_cachep, req);
+                       list_add(&req->inflight_entry, &ctx->submit_state.free_list);
                        break;
                }
                /* will complete beyond this point, count as submitted */