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[PULL 25/30] QIOChannelSocket: Fix zero-copy flush returning code 1 when
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[PULL 25/30] QIOChannelSocket: Fix zero-copy flush returning code 1 when nothing sent |
Date: |
Wed, 20 Jul 2022 12:19:21 +0100 |
From: Leonardo Bras <leobras@redhat.com>
If flush is called when no buffer was sent with MSG_ZEROCOPY, it currently
returns 1. This return code should be used only when Linux fails to use
MSG_ZEROCOPY on a lot of sendmsg().
Fix this by returning early from flush if no sendmsg(...,MSG_ZEROCOPY)
was attempted.
Fixes: 2bc58ffc2926 ("QIOChannelSocket: Implement io_writev zero copy flag &
io_flush for CONFIG_LINUX")
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <20220711211112.18951-2-leobras@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
io/channel-socket.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/io/channel-socket.c b/io/channel-socket.c
index 4466bb1cd4..74a936cc1f 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -716,12 +716,18 @@ static int qio_channel_socket_flush(QIOChannel *ioc,
struct cmsghdr *cm;
char control[CMSG_SPACE(sizeof(*serr))];
int received;
- int ret = 1;
+ int ret;
+
+ if (sioc->zero_copy_queued == sioc->zero_copy_sent) {
+ return 0;
+ }
msg.msg_control = control;
msg.msg_controllen = sizeof(control);
memset(control, 0, sizeof(control));
+ ret = 1;
+
while (sioc->zero_copy_sent < sioc->zero_copy_queued) {
received = recvmsg(sioc->fd, &msg, MSG_ERRQUEUE);
if (received < 0) {
--
2.36.1
- [PULL 09/30] multifd: Copy pages before compressing them with zlib, (continued)
- [PULL 09/30] multifd: Copy pages before compressing them with zlib, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 20/30] tests: Move MigrateCommon upper, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 24/30] migration: remove unreachable code after reading data, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 17/30] migration: Export tls-[creds|hostname|authz] params to cmdline too, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 26/30] Add dirty-sync-missed-zero-copy migration stat, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 21/30] tests: Add postcopy tls migration test, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 23/30] tests: Add postcopy preempt tests, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 30/30] Revert "gitlab: disable accelerated zlib for s390x", Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 27/30] migration/multifd: Report to user when zerocopy not working, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 28/30] multifd: Document the locking of MultiFD{Send/Recv}Params, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 25/30] QIOChannelSocket: Fix zero-copy flush returning code 1 when nothing sent,
Dr. David Alan Gilbert (git) <=
- [PULL 29/30] migration: Avoid false-positive on non-supported scenarios for zero-copy-send, Dr. David Alan Gilbert (git), 2022/07/20
- Re: [PULL 00/30] migration queue, Peter Maydell, 2022/07/21