commit 0543055967e554b5be10c3f96c077bf26dcaf181
author Fam Zheng <famz@redhat.com> Sun Feb 15 11:06:31 2015 +0800
committer Paolo Bonzini <pbonzini@redhat.com> Fri Feb 27 14:43:45 2015 +0100
tree 1bb5eb3c15e524a61b0e183a405e9066a8558df6
parent 2e5b887cfc69991eee27be6cc0938c70a360fe45

virtio-scsi-dataplane: Call blk_set_aio_context within BQL

It's not safe to call blk_set_aio_context from outside BQL because of
the bdrv_drain_all there. Let's put it in the hotplug callback which
will be called by qdev device realization for each scsi device attached
to the bus.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <1423969591-23646-3-git-send-email-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/scsi/virtio-scsi.c

diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index 9e2c718..8c437dd 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -254,10 +254,8 @@
     int target;
     int ret = 0;
 
-    if (s->dataplane_started && blk_get_aio_context(d->conf.blk) != s->ctx) {
-        aio_context_acquire(s->ctx);
-        blk_set_aio_context(d->conf.blk, s->ctx);
-        aio_context_release(s->ctx);
+    if (s->dataplane_started) {
+        assert(blk_get_aio_context(d->conf.blk) == s->ctx);
     }
     /* Here VIRTIO_SCSI_S_OK means "FUNCTION COMPLETE".  */
     req->resp.tmf.response = VIRTIO_SCSI_S_OK;
@@ -540,10 +538,8 @@
         virtio_scsi_complete_cmd_req(req);
         return false;
     }
-    if (s->dataplane_started && blk_get_aio_context(d->conf.blk) != s->ctx) {
-        aio_context_acquire(s->ctx);
-        blk_set_aio_context(d->conf.blk, s->ctx);
-        aio_context_release(s->ctx);
+    if (s->dataplane_started) {
+        assert(blk_get_aio_context(d->conf.blk) == s->ctx);
     }
     req->sreq = scsi_req_new(d, req->req.cmd.tag,
                              virtio_scsi_get_lun(req->req.cmd.lun),
@@ -767,6 +763,9 @@
             return;
         }
         blk_op_block_all(sd->conf.blk, s->blocker);
+        aio_context_acquire(s->ctx);
+        blk_set_aio_context(sd->conf.blk, s->ctx);
+        aio_context_release(s->ctx);
     }
 
     if ((vdev->guest_features >> VIRTIO_SCSI_F_HOTPLUG) & 1) {