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From c1fd32d93ae42fcf3c1a25f4d56e669f251087d8 Mon Sep 17 00:00:00 2001
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From: Leonardo Bras <leobras@redhat.com>
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Date: Mon, 20 Jun 2022 02:39:43 -0300
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Subject: [PATCH 25/37] QIOChannelSocket: Fix zero-copy send so socket flush
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 works
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Leonardo Brás <leobras@redhat.com>
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RH-MergeRequest: 191: MSG_ZEROCOPY + Multifd @ rhel8.7
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RH-Commit: [25/26] 3ede94f3269e21c3ace073ed1a6f24696315bcbb
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RH-Bugzilla: 2072049
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RH-Acked-by: Peter Xu <peterx@redhat.com>
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RH-Acked-by: Daniel P. Berrangé <berrange@redhat.com>
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RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Somewhere between v6 and v7 the of the zero-copy-send patchset a crucial
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part of the flushing mechanism got missing: incrementing zero_copy_queued.
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Without that, the flushing interface becomes a no-op, and there is no
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guarantee the buffer is really sent.
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This can go as bad as causing a corruption in RAM during migration.
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Fixes: 2bc58ffc2926 ("QIOChannelSocket: Implement io_writev zero copy flag & io_flush for CONFIG_LINUX")
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Reported-by: 徐闯 <xuchuangxclwt@bytedance.com>
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Signed-off-by: Leonardo Bras <leobras@redhat.com>
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Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
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Reviewed-by: Peter Xu <peterx@redhat.com>
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Reviewed-by: Juan Quintela <quintela@redhat.com>
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Signed-off-by: Juan Quintela <quintela@redhat.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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(cherry picked from commit 4f5a09714c983a3471fd12e3c7f3196e95c650c1)
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Signed-off-by: Leonardo Bras <leobras@redhat.com>
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---
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 io/channel-socket.c | 5 +++++
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 1 file changed, 5 insertions(+)
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diff --git a/io/channel-socket.c b/io/channel-socket.c
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index 7d37b39de7..df858da924 100644
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--- a/io/channel-socket.c
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+++ b/io/channel-socket.c
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@@ -612,6 +612,11 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc,
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                          "Unable to write to socket");
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         return -1;
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     }
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+
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+    if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) {
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+        sioc->zero_copy_queued++;
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+    }
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+
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     return ret;
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 }
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 #else /* WIN32 */
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-- 
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2.35.3
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