From: Maxim Levitsky <mlevitsk@redhat.com>
To: qemu-devel@nongnu.org
Cc: Fam Zheng <fam@euphon.net>, Paolo Bonzini <pbonzini@redhat.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: [PATCH 3/3] event_notifier: handle initialization failure better
Date: Thu, 17 Dec 2020 17:00:40 +0200 [thread overview]
Message-ID: <20201217150040.906961-4-mlevitsk@redhat.com> (raw)
In-Reply-To: <20201217150040.906961-1-mlevitsk@redhat.com>
Add 'initialized' field and use it to avoid touching event notifiers which are
either not initialized or if their initialization failed.
This is somewhat a hack, but it seems the less intrusive way to make
virtio code deal with event notifiers that failed initialization.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
include/qemu/event_notifier.h | 1 +
util/event_notifier-posix.c | 16 ++++++++++++++++
2 files changed, 17 insertions(+)
diff --git a/include/qemu/event_notifier.h b/include/qemu/event_notifier.h
index 3380b662f3..b79add035d 100644
--- a/include/qemu/event_notifier.h
+++ b/include/qemu/event_notifier.h
@@ -24,6 +24,7 @@ struct EventNotifier {
#else
int rfd;
int wfd;
+ bool initialized;
#endif
};
diff --git a/util/event_notifier-posix.c b/util/event_notifier-posix.c
index 00d93204f9..5b2110e861 100644
--- a/util/event_notifier-posix.c
+++ b/util/event_notifier-posix.c
@@ -29,6 +29,7 @@ void event_notifier_init_fd(EventNotifier *e, int fd)
{
e->rfd = fd;
e->wfd = fd;
+ e->initialized = true;
}
#endif
@@ -68,6 +69,7 @@ int event_notifier_init(EventNotifier *e, int active)
if (active) {
event_notifier_set(e);
}
+ e->initialized = true;
return 0;
fail:
@@ -78,12 +80,18 @@ fail:
void event_notifier_cleanup(EventNotifier *e)
{
+ if (!e->initialized) {
+ return;
+ }
+
if (e->rfd != e->wfd) {
close(e->rfd);
}
+
e->rfd = -1;
close(e->wfd);
e->wfd = -1;
+ e->initialized = false;
}
int event_notifier_get_fd(const EventNotifier *e)
@@ -96,6 +104,10 @@ int event_notifier_set(EventNotifier *e)
static const uint64_t value = 1;
ssize_t ret;
+ if (!e->initialized) {
+ return -1;
+ }
+
do {
ret = write(e->wfd, &value, sizeof(value));
} while (ret < 0 && errno == EINTR);
@@ -113,6 +125,10 @@ int event_notifier_test_and_clear(EventNotifier *e)
ssize_t len;
char buffer[512];
+ if (!e->initialized) {
+ return 0;
+ }
+
/* Drain the notify pipe. For eventfd, only 8 bytes will be read. */
value = 0;
do {
--
2.26.2
next prev parent reply other threads:[~2020-12-17 15:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-17 15:00 [PATCH 0/3] RFC: few random hacks to improve eventfd fallback path Maxim Levitsky
2020-12-17 15:00 ` [PATCH 1/3] scsi: virtio-scsi: don't process IO on fenced dataplane Maxim Levitsky
2020-12-17 15:00 ` [PATCH 2/3] virtio-scsi: don't uninitialize queues that we didn't initialize Maxim Levitsky
2020-12-17 15:00 ` Maxim Levitsky [this message]
2021-01-07 10:26 ` [PATCH 0/3] RFC: few random hacks to improve eventfd fallback path Maxim Levitsky
2021-01-13 14:38 ` Paolo Bonzini
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