blkback-be-mutex.diff

diff -r 2eacc3b7dcc5 drivers/xen/blkback/blkback.c
--- a/drivers/xen/blkback/blkback.c	Thu Jun 24 23:17:00 2010 -0700
+++ b/drivers/xen/blkback/blkback.c	Thu Jun 24 23:17:47 2010 -0700
@@ -456,7 +456,7 @@
 	if (debug_lvl)
 		printk(KERN_DEBUG "%s: exiting\n", current->comm);
 
-	blkback_close(blkif);
+	blkback_close(blkif->be);
 
 	return 0;
 }
diff -r 2eacc3b7dcc5 drivers/xen/blkback/common.h
--- a/drivers/xen/blkback/common.h	Thu Jun 24 23:17:00 2010 -0700
+++ b/drivers/xen/blkback/common.h	Thu Jun 24 23:17:47 2010 -0700
@@ -151,6 +151,6 @@
 void blkback_resume(blkif_t *blkif);
 void blkback_signal_resumed(blkif_t *blkif);
 
-void blkback_close(blkif_t *blkif);
+void blkback_close(struct backend_info *be);
 
 #endif /* __BLKIF__BACKEND__COMMON_H__ */
diff -r 2eacc3b7dcc5 drivers/xen/blkback/xenbus.c
--- a/drivers/xen/blkback/xenbus.c	Thu Jun 24 23:17:00 2010 -0700
+++ b/drivers/xen/blkback/xenbus.c	Thu Jun 24 23:17:47 2010 -0700
@@ -29,6 +29,7 @@
 
 struct backend_info
 {
+	struct mutex mutex;
 	struct xenbus_device *dev;
 	blkif_t *blkif;
 	struct xenbus_watch backend_watch;
@@ -42,8 +43,6 @@
 	int shutdown_signalled;
 };
 
-DECLARE_MUTEX(blkback_dev_sem);
-
 static void connect(struct backend_info *);
 static int connect_ring(struct backend_info *);
 static void backend_changed(struct xenbus_watch *, const char **,
@@ -206,11 +205,11 @@
 
 	/* NB. this should actually be a link to /sys/block. */
 
-	down(&blkback_dev_sem);
+	mutex_lock(&be->mutex);
 	bdev = blkif->bdev;
 	if (bdev)
 		rdev = bdev->bd_inode->i_rdev;
-	up(&blkback_dev_sem);
+	mutex_unlock(&be->mutex);
 
 	if (rdev)
 		rv = sprintf(buf, "%x:%x\n", MAJOR(rdev), MINOR(rdev));
@@ -275,7 +274,7 @@
 	struct xenbus_device *xbdev = be->dev;
 	int err;
 
-	down(&blkback_dev_sem);
+	mutex_lock(&be->mutex);
 
 	if (be->shutdown_signalled)
 		goto out;
@@ -291,7 +290,7 @@
 	be->shutdown_signalled = 1;
 
  out:
-	up(&blkback_dev_sem);
+	mutex_unlock(&be->mutex);
 }
 
 static void backend_release(struct backend_info *be)
@@ -320,9 +319,9 @@
 {
 	struct backend_info *be = xbdev->dev.driver_data;
 
-	down(&blkback_dev_sem);
+	mutex_lock(&be->mutex);
 	be->dev = NULL;
-	up(&blkback_dev_sem);
+	mutex_unlock(&be->mutex);
 
 	if (be->backend_watch.node) {
 		unregister_xenbus_watch(&be->backend_watch);
@@ -356,18 +355,20 @@
 /*
  * called by kthread when closing
  */
-void blkback_close(blkif_t *blkif)
+void blkback_close(struct backend_info *be)
 {
+	blkif_t *blkif = be->blkif;
+
 	blkif_disconnect(blkif);
 
-	down(&blkback_dev_sem);
+	mutex_lock(&be->mutex);
 
 	blkif_bdev_close(blkif);
 	blkif->be->major = 0;
 	blkif->be->minor = 0;
 	blkif->remove_requested = 0;
 
-	up(&blkback_dev_sem);
+	mutex_unlock(&be->mutex);
 
 	blkif->xenblkd = NULL;
 	backend_release(blkif->be);
@@ -435,14 +436,14 @@
 	int err;
 	struct backend_info *be = blkif->be;
 
-	down(&blkback_dev_sem);
+	mutex_lock(&be->mutex);
 	if (be->dev) {
 		err = xenbus_write(XBT_NIL,
 				   be->dev->nodename, "pause-done", "");
 		if (err)
 			xenbus_dev_error(be->dev, err, "writing pause-done");
 	}
-	up(&blkback_dev_sem);
+	mutex_unlock(&be->mutex);
 }
 
 void blkback_signal_resumed(blkif_t *blkif)
@@ -450,7 +451,7 @@
 	int err;
 	struct backend_info *be = blkif->be;
 
-	down(&blkback_dev_sem);
+	mutex_lock(&be->mutex);
 	if (be->dev) {
 		if (blkif->bdev &&
 		    be->dev->state == XenbusStateConnected)
@@ -460,7 +461,7 @@
 		if (err)
 			xenbus_dev_error(be->dev, err, "removing pause-done");
 	}
-	up(&blkback_dev_sem);
+	mutex_unlock(&be->mutex);
 }
 
 static void backend_pause(struct xenbus_watch *watch,
@@ -519,6 +520,7 @@
 	be->dev = dev;
 	dev->dev.driver_data = be;
 	atomic_set(&be->refcnt, 1);
+	mutex_init(&be->mutex);
 
 	be->blkif = blkif_alloc(dev->otherend_id);
 	if (IS_ERR(be->blkif)) {