trace: Trace bdrv_set_locked()

It can be handy to know when the guest locks/unlocks the CD-ROM tray.
This trace event makes that possible.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

diff --git a/block.c b/block.c
index c93ec6d..d8da3b0 100644
--- a/block.c
+++ b/block.c
@@ -2817,6 +2817,8 @@
 {
     BlockDriver *drv = bs->drv;
 
+    trace_bdrv_set_locked(bs, locked);
+
     bs->locked = locked;
     if (drv && drv->bdrv_set_locked) {
         drv->bdrv_set_locked(bs, locked);

trace-events

diff --git a/trace-events b/trace-events
index 06efdb7..703b745 100644
--- a/trace-events
+++ b/trace-events
@@ -54,6 +54,7 @@
 disable bdrv_aio_flush(void *bs, void *opaque) "bs %p opaque %p"
 disable bdrv_aio_readv(void *bs, int64_t sector_num, int nb_sectors, void *opaque) "bs %p sector_num %"PRId64" nb_sectors %d opaque %p"
 disable bdrv_aio_writev(void *bs, int64_t sector_num, int nb_sectors, void *opaque) "bs %p sector_num %"PRId64" nb_sectors %d opaque %p"
+disable bdrv_set_locked(void *bs, int locked) "bs %p locked %d"
 
 # hw/virtio-blk.c
 disable virtio_blk_req_complete(void *req, int status) "req %p status %d"