From 81bdf75b893c852a9daae615b4ab41106eb364db Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Thu, 18 Jan 2018 12:12:04 +0100
Subject: [PATCH 06/21] scsi-disk: release AioContext in unaligned WRITE SAME
 case

RH-Author: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: <20180118121204.17287-2-stefanha@redhat.com>
Patchwork-id: 78663
O-Subject: [RHV7.5 qemu-kvm-rhev PATCH 1/1] scsi-disk: release AioContext in unaligned WRITE SAME case
Bugzilla: 1526423
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

scsi_write_same_complete() can retry the write if the request was
unaligned.  Make sure to release the AioContext when that code path is
taken!

This patch fixes a hang when QEMU terminates after an unaligned WRITE
SAME request has been processed with dataplane.  The hang occurs because
iothread_stop_all() cannot acquire the AioContext lock that was leaked
by the IOThread in scsi_write_same_complete().

Fixes: b9e413dd37 ("block: explicitly acquire aiocontext in aio callbacks that need it").
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-stable@nongnu.org
Reported-by: Cong Li <coli@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20180104142502.15175-1-stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 24355b79bdaf6ab12f7c610b032fc35ec045cd55)
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/scsi/scsi-disk.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index c676355..25cbd7b 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -1747,6 +1747,7 @@ static void scsi_write_same_complete(void *opaque, int ret)
                                        data->sector << BDRV_SECTOR_BITS,
                                        &data->qiov, 0,
                                        scsi_write_same_complete, data);
+        aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
         return;
     }
 
-- 
1.8.3.1