diff mbox series

[PULL,for-5.0,1/3] aio-posix: signal-proof fdmon-io_uring

Message ID 20200409174209.321725-2-stefanha@redhat.com
State New
Headers show
Series Block patches | expand

Commit Message

Stefan Hajnoczi April 9, 2020, 5:42 p.m. UTC 
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 <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20200408091139.273851-1-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 util/fdmon-io_uring.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
diff mbox series

Patch

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);