# HG changeset patch
# User cl349@xxxxxxxxxxxxxxxxxxxx
# Node ID 969b33e87e0a180ca4b2e6513ea1c0d5ccf81c82
# Parent a8da66acde0c2c06c85476c62e287bd1201a0715
Do not create blkback vbd kernel thread until fully connected
to frontend driver. Otherwise the kernel thread may crash trying
to access the non-existent shared ring.
Replaces xen-3.0-testing cset: 9595:32b22f5286beba94318e60704a8058ac3833d502
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
xen-unstable changeset: 9571:24d25894f071bed67d5547c1790a075271ab1174
xen-unstable date: Thu Apr 6 18:39:00 2006 +0100
diff -r a8da66acde0c -r 969b33e87e0a
linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c
--- a/linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c Sat Apr 22
10:42:34 2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c Mon Apr 24
18:06:10 2006 +0100
@@ -221,14 +221,6 @@ int blkif_schedule(void *arg)
if (debug_lvl)
printk(KERN_DEBUG "%s: started\n", current->comm);
-
- /*
- * This thread may start before we are connected to the frontend
- * driver. In that case we must wait to be fully connected.
- */
- wait_event_interruptible(
- blkif->wq,
- blkif_connected(blkif) || kthread_should_stop());
while (!kthread_should_stop()) {
wait_event_interruptible(
diff -r a8da66acde0c -r 969b33e87e0a
linux-2.6-xen-sparse/drivers/xen/blkback/common.h
--- a/linux-2.6-xen-sparse/drivers/xen/blkback/common.h Sat Apr 22 10:42:34
2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/blkback/common.h Mon Apr 24 18:06:10
2006 +0100
@@ -135,8 +135,6 @@ int blkif_schedule(void *arg);
void update_blkif_status(blkif_t *blkif);
-int blkif_connected(blkif_t *blkif);
-
#endif /* __BLKIF__BACKEND__COMMON_H__ */
/*
diff -r a8da66acde0c -r 969b33e87e0a
linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
--- a/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c Sat Apr 22 10:42:34
2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c Mon Apr 24 18:06:10
2006 +0100
@@ -47,18 +47,33 @@ static void backend_changed(struct xenbu
static void backend_changed(struct xenbus_watch *, const char **,
unsigned int);
-int blkif_connected(blkif_t *blkif)
-{
- return (blkif->be->dev->state == XenbusStateConnected);
-}
-
-void update_blkif_status(blkif_t *blkif)
+
+static void update_blkif_status(blkif_t *blkif)
{
- if(blkif->irq && blkif->vbd.bdev) {
- blkif->status = CONNECTED;
- (void)blkif_be_int(0, blkif, NULL);
- }
- maybe_connect(blkif->be);
+ int err;
+
+ /* Not ready to connect? */
+ if (!blkif->irq || !blkif->vbd.bdev)
+ return;
+
+ /* Already connected? */
+ if (blkif->be->dev->state == XenbusStateConnected)
+ return;
+
+ /* Attempt to connect: exit if we fail to. */
+ connect(blkif->be);
+ if (blkif->be->dev->state != XenbusStateConnected)
+ return;
+
+ blkif->xenblkd = kthread_run(blkif_schedule, blkif,
+ "xvd %d %02x:%02x",
+ blkif->domid,
+ blkif->be->major, blkif->be->minor);
+ if (IS_ERR(blkif->xenblkd)) {
+ err = PTR_ERR(blkif->xenblkd);
+ blkif->xenblkd = NULL;
+ xenbus_dev_error(blkif->be->dev, err, "start xenblkd");
+ }
}
@@ -224,17 +239,6 @@ static void backend_changed(struct xenbu
return;
}
- be->blkif->xenblkd = kthread_run(blkif_schedule, be->blkif,
- "xvd %d %02x:%02x",
- be->blkif->domid,
- be->major, be->minor);
- if (IS_ERR(be->blkif->xenblkd)) {
- err = PTR_ERR(be->blkif->xenblkd);
- be->blkif->xenblkd = NULL;
- xenbus_dev_error(dev, err, "start xenblkd");
- return;
- }
-
device_create_file(&dev->dev, &dev_attr_physical_device);
device_create_file(&dev->dev, &dev_attr_mode);
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