From 93bd25bb69f46367ba8f82c578e0c05702ceb482 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 11 Nov 2019 23:34:31 -0700 Subject: [PATCH] io_uring: make timeout sequence == 0 mean no sequence MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently we make sequence == 0 be the same as sequence == 1, but that's not super useful if the intent is really to have a timeout that's just a pure timeout. If the user passes in sqe->off == 0, then don't apply any sequence logic to the request, let it purely be driven by the timeout specified. Reported-by: 李通洲 Reviewed-by: 李通洲 Signed-off-by: Jens Axboe --- fs/io_uring.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index f9a38998f2fc..87beca4377f7 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -326,6 +326,7 @@ struct io_kiocb { #define REQ_F_TIMEOUT 1024 /* timeout request */ #define REQ_F_ISREG 2048 /* regular file */ #define REQ_F_MUST_PUNT 4096 /* must be punted even for NONBLOCK */ +#define REQ_F_TIMEOUT_NOSEQ 8192 /* no timeout sequence */ u64 user_data; u32 result; u32 sequence; @@ -453,9 +454,13 @@ static struct io_kiocb *io_get_timeout_req(struct io_ring_ctx *ctx) struct io_kiocb *req; req = list_first_entry_or_null(&ctx->timeout_list, struct io_kiocb, list); - if (req && !__io_sequence_defer(ctx, req)) { - list_del_init(&req->list); - return req; + if (req) { + if (req->flags & REQ_F_TIMEOUT_NOSEQ) + return NULL; + if (!__io_sequence_defer(ctx, req)) { + list_del_init(&req->list); + return req; + } } return NULL; @@ -1941,18 +1946,24 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe) if (get_timespec64(&ts, u64_to_user_ptr(sqe->addr))) return -EFAULT; + req->flags |= REQ_F_TIMEOUT; + /* * sqe->off holds how many events that need to occur for this - * timeout event to be satisfied. + * timeout event to be satisfied. If it isn't set, then this is + * a pure timeout request, sequence isn't used. */ count = READ_ONCE(sqe->off); - if (!count) - count = 1; + if (!count) { + req->flags |= REQ_F_TIMEOUT_NOSEQ; + spin_lock_irq(&ctx->completion_lock); + entry = ctx->timeout_list.prev; + goto add; + } req->sequence = ctx->cached_sq_head + count - 1; /* reuse it to store the count */ req->submit.sequence = count; - req->flags |= REQ_F_TIMEOUT; /* * Insertion sort, ensuring the first entry in the list is always @@ -1964,6 +1975,9 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe) unsigned nxt_sq_head; long long tmp, tmp_nxt; + if (nxt->flags & REQ_F_TIMEOUT_NOSEQ) + continue; + /* * Since cached_sq_head + count - 1 can overflow, use type long * long to store it. @@ -1990,6 +2004,7 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe) nxt->sequence++; } req->sequence -= span; +add: list_add(&req->list, entry); spin_unlock_irq(&ctx->completion_lock); -- GitLab