diff options
| author | Maxim Levitsky <mlevitsk@redhat.com> | 2020-10-06 15:38:59 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-10-12 11:50:50 -0400 |
| commit | 2d24a64661549732fc77f632928318dd52f5bce5 (patch) | |
| tree | 3e7f20a87ef9c2368db3f988fe331279cacf236a /hw/scsi/virtio-scsi.c | |
| parent | 7bed89958bfbf40df9ca681cefbdca63abdde39d (diff) | |
device-core: use RCU for list of children of a bus
This fixes the race between device emulation code that tries to find
a child device to dispatch the request to (e.g a scsi disk),
and hotplug of a new device to that bus.
Note that this doesn't convert all the readers of the list
but only these that might go over that list without BQL held.
This is a very small first step to make this code thread safe.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200913160259.32145-5-mlevitsk@redhat.com>
[Use RCU_READ_LOCK_GUARD in more places, adjust testcase now that
the delay in DEVICE_DELETED due to RCU is more consistent. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20201006123904.610658-9-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'hw/scsi/virtio-scsi.c')
| -rw-r--r-- | hw/scsi/virtio-scsi.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c index 3a71ea7097..971afbb217 100644 --- a/hw/scsi/virtio-scsi.c +++ b/hw/scsi/virtio-scsi.c @@ -367,12 +367,16 @@ static int virtio_scsi_do_tmf(VirtIOSCSI *s, VirtIOSCSIReq *req) case VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET: target = req->req.tmf.lun[1]; s->resetting++; - QTAILQ_FOREACH(kid, &s->bus.qbus.children, sibling) { + + rcu_read_lock(); + QTAILQ_FOREACH_RCU(kid, &s->bus.qbus.children, sibling) { d = SCSI_DEVICE(kid->child); if (d->channel == 0 && d->id == target) { qdev_reset_all(&d->qdev); } } + rcu_read_unlock(); + s->resetting--; break; |