From 9a4ecf0b3cfccd31a1d41716e3a4249a1d53455c Mon Sep 17 00:00:00 2001 From: Leonardo Bras Date: Mon, 20 Jun 2022 02:39:43 -0300 Subject: [PATCH 25/34] QIOChannelSocket: Fix zero-copy send so socket flush works MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Leonardo Brás RH-MergeRequest: 185: MSG_ZEROCOPY + Multifd @ rhel8.6 RH-Commit: [25/34] cf8dc62075bc8b9aa2621315842a2b2458e9cd82 RH-Bugzilla: 2117252 RH-Acked-by: quintela1 RH-Acked-by: Dr. David Alan Gilbert RH-Acked-by: Peter Xu Somewhere between v6 and v7 the of the zero-copy-send patchset a crucial part of the flushing mechanism got missing: incrementing zero_copy_queued. Without that, the flushing interface becomes a no-op, and there is no guarantee the buffer is really sent. This can go as bad as causing a corruption in RAM during migration. Fixes: 2bc58ffc2926 ("QIOChannelSocket: Implement io_writev zero copy flag & io_flush for CONFIG_LINUX") Reported-by: 徐闯 Signed-off-by: Leonardo Bras Reviewed-by: Daniel P. Berrangé Reviewed-by: Peter Xu Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela Signed-off-by: Dr. David Alan Gilbert (cherry picked from commit 4f5a09714c983a3471fd12e3c7f3196e95c650c1) Signed-off-by: Leonardo Bras --- io/channel-socket.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/io/channel-socket.c b/io/channel-socket.c index 7d37b39de7..df858da924 100644 --- a/io/channel-socket.c +++ b/io/channel-socket.c @@ -612,6 +612,11 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc, "Unable to write to socket"); return -1; } + + if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) { + sioc->zero_copy_queued++; + } + return ret; } #else /* WIN32 */ -- 2.35.3