From: Pavel Begunkov <asml.silence@gmail.com> mainline inclusion from mainline-5.9-rc1 commit 27dc8338e5fb0e0ed5b272e792f4ffad7f3bc03e category: feature bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27 CVE: NA --------------------------- The only left user of req->list is DRAIN, hence instead of keeping a separate per request list for it, do that with old fashion non-intrusive lists allocated on demand. That's a really slow path, so that's OK. This removes req->list and so sheds 16 bytes from io_kiocb. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Conflicts: fs/io_uring.c [ac8691c415e0 ("io_uring: always plug for any number of IOs") not include] Signed-off-by: yangerkun <yangerkun@huawei.com> Reviewed-by: zhangyi (F) <yi.zhang@huawei.com> Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> --- fs/io_uring.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 119b7ab91718..4fa5633c8661 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -652,7 +652,6 @@ struct io_kiocb { u16 buf_index; struct io_ring_ctx *ctx; - struct list_head list; unsigned int flags; refcount_t refs; struct task_struct *task; @@ -687,6 +686,11 @@ struct io_kiocb { struct callback_head task_work; }; +struct io_defer_entry { + struct list_head list; + struct io_kiocb *req; +}; + #define IO_PLUG_THRESHOLD 2 #define IO_IOPOLL_BATCH 8 @@ -1293,14 +1297,15 @@ static void io_kill_timeouts(struct io_ring_ctx *ctx) static void __io_queue_deferred(struct io_ring_ctx *ctx) { do { - struct io_kiocb *req = list_first_entry(&ctx->defer_list, - struct io_kiocb, list); + struct io_defer_entry *de = list_first_entry(&ctx->defer_list, + struct io_defer_entry, list); - if (req_need_defer(req)) + if (req_need_defer(de->req)) break; - list_del_init(&req->list); + list_del_init(&de->list); /* punt-init is done before queueing for defer */ - __io_queue_async_work(req); + __io_queue_async_work(de->req); + kfree(de); } while (!list_empty(&ctx->defer_list)); } @@ -5293,6 +5298,7 @@ static int io_req_defer_prep(struct io_kiocb *req, static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; + struct io_defer_entry *de; int ret; /* Still need defer if there is pending req in defer list. */ @@ -5307,15 +5313,20 @@ static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe) return ret; } io_prep_async_link(req); + de = kmalloc(sizeof(*de), GFP_KERNEL); + if (!de) + return -ENOMEM; spin_lock_irq(&ctx->completion_lock); if (!req_need_defer(req) && list_empty(&ctx->defer_list)) { spin_unlock_irq(&ctx->completion_lock); + kfree(de); return 0; } trace_io_uring_defer(ctx, req, req->user_data); - list_add_tail(&req->list, &ctx->defer_list); + de->req = req; + list_add_tail(&de->list, &ctx->defer_list); spin_unlock_irq(&ctx->completion_lock); return -EIOCBQUEUED; } -- 2.25.1