From 636b836d5f4e36ceebb788e2e0d4724f7f9406e1 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Wed, 8 Apr 2020 10:11:39 +0100 Subject: [PATCH] aio-posix: signal-proof fdmon-io_uring MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The io_uring_enter(2) syscall returns with errno=EINTR when interrupted by a signal. Retry the syscall in this case. It's essential to do this in the io_uring_submit_and_wait() case. My interpretation of the Linux v5.5 io_uring_enter(2) code is that it shouldn't affect the io_uring_submit() case, but there is no guarantee this will always be the case. Let's check for -EINTR around both APIs. Note that the liburing APIs have -errno return values. Signed-off-by: Stefan Hajnoczi Reviewed-by: Stefano Garzarella Reviewed-by: Philippe Mathieu-Daudé Message-id: 20200408091139.273851-1-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi --- util/fdmon-io_uring.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/util/fdmon-io_uring.c b/util/fdmon-io_uring.c index b4d6109f20..d5a80ed6fb 100644 --- a/util/fdmon-io_uring.c +++ b/util/fdmon-io_uring.c @@ -88,7 +88,10 @@ static struct io_uring_sqe *get_sqe(AioContext *ctx) } /* No free sqes left, submit pending sqes first */ - ret = io_uring_submit(ring); + do { + ret = io_uring_submit(ring); + } while (ret == -EINTR); + assert(ret > 1); sqe = io_uring_get_sqe(ring); assert(sqe); @@ -282,7 +285,10 @@ static int fdmon_io_uring_wait(AioContext *ctx, AioHandlerList *ready_list, fill_sq_ring(ctx); - ret = io_uring_submit_and_wait(&ctx->fdmon_io_uring, wait_nr); + do { + ret = io_uring_submit_and_wait(&ctx->fdmon_io_uring, wait_nr); + } while (ret == -EINTR); + assert(ret >= 0); return process_cq_ring(ctx, ready_list);