blkback-blkif-start.diff

blkback:

diff -r 29dcb13e81ab drivers/xen/blkback/blkback.c
--- a/drivers/xen/blkback/blkback.c	Thu Jun 24 19:59:20 2010 -0700
+++ b/drivers/xen/blkback/blkback.c	Thu Jun 24 21:33:31 2010 -0700
@@ -415,7 +415,8 @@
 	blkif->st_oo_req = 0;
 }
 
-int blkif_schedule(void *arg)
+static int
+blkif_queue_run(void *arg)
 {
 	blkif_t *blkif = arg;
 
@@ -456,11 +457,50 @@
 	if (debug_lvl)
 		printk(KERN_DEBUG "%s: exiting\n", current->comm);
 
+	blkif->remove_requested = 0;
+	blkif->xenblkd = NULL;
 	blkback_close(blkif->be);
 
 	return 0;
 }
 
+pid_t
+blkif_queue_start(blkif_t *blkif, const char *devname)
+{
+	struct task_struct *tsk;
+	const char *p;
+
+	BUG_ON(!blkif->bdev);
+	BUG_ON(!blkif->blk_rings.common.sring);
+	BUG_ON(blkif->xenblkd);
+
+	p = strrchr(devname, '/');
+	devname = p ? p + 1 : devname;
+
+	tsk = kthread_run(blkif_queue_run, blkif,
+			  "xb.%05d.%s", blkif->domid, devname);
+	if (IS_ERR(tsk))
+		return PTR_ERR(tsk);
+
+	blkif->xenblkd = tsk;
+
+	return tsk->pid;
+}
+
+int
+blkif_queue_stop(blkif_t *blkif)
+{
+	int err = 0;
+
+	if (blkif->xenblkd) {
+		blkif->remove_requested = 1;
+		wake_up_process(blkif->xenblkd);
+		err = -EBUSY;
+	}
+
+	return err;
+}
+
 /******************************************************************
  * COMPLETION CALLBACK -- Called as bh->b_end_io()
  */
diff -r 29dcb13e81ab drivers/xen/blkback/common.h
--- a/drivers/xen/blkback/common.h	Thu Jun 24 19:59:20 2010 -0700
+++ b/drivers/xen/blkback/common.h	Thu Jun 24 21:33:31 2010 -0700
@@ -127,6 +127,9 @@
 int blkif_sector_size(blkif_t *blkif);
 unsigned int blkif_info(blkif_t *blkif);
 
+pid_t blkif_queue_start(blkif_t *blkif, const char *name);
+int blkif_queue_stop(blkif_t *blkif);
+
 struct phys_req {
 	unsigned short       dev;
 	unsigned short       nr_sects;
@@ -139,7 +142,6 @@
 void blkif_xenbus_init(void);
 
 irqreturn_t blkif_be_int(int irq, void *dev_id);
-int blkif_schedule(void *arg);
 
 void blkif_notify_work(blkif_t *blkif);
 
diff -r 29dcb13e81ab drivers/xen/blkback/xenbus.c
--- a/drivers/xen/blkback/xenbus.c	Thu Jun 24 19:59:20 2010 -0700
+++ b/drivers/xen/blkback/xenbus.c	Thu Jun 24 21:33:31 2010 -0700
@@ -31,6 +31,7 @@
 {
 	struct mutex mutex;
 	struct xenbus_device *dev;
+	char *devname;
 	blkif_t *blkif;
 	struct xenbus_watch backend_watch;
 	struct xenbus_watch shutdown_watch;
@@ -53,67 +54,56 @@
 module_param_named(max_ring_page_order, blkif_max_ring_page_order, int, 0);
 MODULE_PARM_DESC(max_ring_page_order, "Order of maximum VM shared ring size");
 
-static int blkback_name(blkif_t *blkif, char *buf)
+static void
+blkback_queue_start(struct backend_info *be)
 {
-	char *devpath, *devname;
-	struct xenbus_device *dev = blkif->be->dev;
+	struct xenbus_device *xbdev = be->dev;
+	blkif_t *blkif = be->blkif;
+	pid_t pid;
+	int err;
 
-	devpath = xenbus_read(XBT_NIL, dev->nodename, "dev", NULL);
-	if (IS_ERR(devpath)) 
-		return PTR_ERR(devpath);
-	
-	if ((devname = strstr(devpath, "/dev/")) != NULL)
-		devname += strlen("/dev/");
-	else
-		devname  = devpath;
+	pid = blkif_queue_start(blkif, be->devname);
+	if (pid < 0) {
+		xenbus_dev_fatal(xbdev, pid, "starting xenblkd");
+		blkif_bdev_close(blkif);
+		return;
+	}
 
-	snprintf(buf, TASK_COMM_LEN, "xb.%05d.%s", blkif->domid, devname);
-	kfree(devpath);
-	
-	return 0;
+	be->kthread_pid = pid;
+	atomic_inc(&be->refcnt);
+
+	err = xenbus_printf(XBT_NIL, xbdev->nodename, "kthread-pid",
+			    "%d", be->kthread_pid);
+	if (err) {
+		xenbus_dev_fatal(xbdev, err, "write kthread-pid");
+		blkif_queue_stop(blkif);
+		return;
+	}
 }
 
 static void update_blkif_status(blkif_t *blkif)
-{ 
-	int err;
-	char name[TASK_COMM_LEN];
+{
+	struct backend_info *be = blkif->be;
+	struct xenbus_device *xbdev = be->dev;
+
+	printk(KERN_DEBUG
+	       "update_blkif_status: irq=%d, bdev=%p, state=%d\n",
+	       blkif->irq, blkif->bdev, xbdev->state);
 
 	/* Not ready to connect? */
 	if (!blkif->irq || !blkif->bdev)
 		return;
 
 	/* Already connected? */
-	if (blkif->be->dev->state == XenbusStateConnected)
+	if (xbdev->state == XenbusStateConnected)
 		return;
 
 	/* Attempt to connect: exit if we fail to. */
-	connect(blkif->be);
-	if (blkif->be->dev->state != XenbusStateConnected)
+	connect(be);
+	if (xbdev->state != XenbusStateConnected)
 		return;
 
-	err = blkback_name(blkif, name);
-	if (err) {
-		xenbus_dev_error(blkif->be->dev, err, "get blkback dev name");
-		return;
-	}
-
-	blkif->xenblkd = kthread_run(blkif_schedule, blkif, name);
-	if (IS_ERR(blkif->xenblkd)) {
-		err = PTR_ERR(blkif->xenblkd);
-		blkif->xenblkd = NULL;
-		xenbus_dev_error(blkif->be->dev, err, "start xenblkd");
-		return;
-	}
-	
-	blkif->be->kthread_pid = blkif->xenblkd->pid;
-	atomic_inc(&blkif->be->refcnt);
-
-	err = xenbus_printf(XBT_NIL, blkif->be->dev->nodename, "kthread-pid",
-			    "%d", blkif->xenblkd->pid);
-	if (err) {
-		xenbus_dev_error(blkif->be->dev, err, "write kthread-pid");
-		return;
-	}
+	blkback_queue_start(be);
 }
 
 
@@ -258,19 +248,6 @@
 	be->group_added = 0;
 }
 
-static int kthread_remove(struct backend_info *be)
-{
-	blkif_t *blkif = be->blkif;
-
-	if (!blkif || !blkif->xenblkd)
-		return 0;
-
-	blkif->remove_requested = 1;
-	wake_up_process(blkif->xenblkd);
-
-	return -EBUSY;
-}
-
 static void signal_shutdown(struct backend_info *be)
 {
 	struct xenbus_device *xbdev = be->dev;
@@ -343,10 +320,11 @@
 		be->pause_watch.node = NULL;
 	}
 
-	if (kthread_remove(be))
+	if (blkif_queue_stop(be->blkif))
 		WPRINTK("BAD REMOVE REQUEST for %s\n", xbdev->nodename);
 
 	xenvbd_sysfs_delif(xbdev);
+	kfree(be->devname);
 	backend_release(be);
 
 	xbdev->dev.driver_data = NULL;
@@ -368,11 +346,10 @@
 	blkif_bdev_close(blkif);
 	blkif->be->major = 0;
 	blkif->be->minor = 0;
-	blkif->remove_requested = 0;
 
+	be->kthread_pid = 0;
 	mutex_unlock(&be->mutex);
 
-	blkif->xenblkd = NULL;
 	backend_release(blkif->be);
 }
 
@@ -427,7 +404,7 @@
 	xenbus_write_state(dev, XenbusStateClosing);
 	
 	if (len == sizeof("force") - 1 && !memcmp(type, "force", len))
-		if (!kthread_remove(be))
+		if (!blkif_queue_stop(be->blkif))
 			signal_shutdown(be); /* shutdown immediately */
 
 	kfree(type);
@@ -535,6 +512,13 @@
 	/* setup back pointer */
 	be->blkif->be = be;
 
+	be->devname = xenbus_read(XBT_NIL, dev->nodename, "dev", NULL);
+	if (IS_ERR(be->devname)) {
+		err = PTR_ERR(be->devname);
+		xenbus_dev_fatal(dev, err, "reading dev");
+		goto fail;
+	}
+
 	err = xenvbd_sysfs_addif(dev);
 	if (err) {
 		xenbus_dev_fatal(dev, err, "creating sysfs entries");
@@ -725,7 +709,7 @@
 		break;
 
 	case XenbusStateClosed:
-		if (!kthread_remove(be))
+		if (!blkif_queue_stop(be->blkif))
 			signal_shutdown(be);
 		break;