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authorChristian Limpach <Christian.Limpach@xensource.com>2008-04-02 10:54:04 -0700
committerIngo Molnar <mingo@elte.hu>2008-04-24 23:57:33 +0200
commit1d78d7055629e3f6300d6b8d7028259ee2bffc0e (patch)
tree20bf47ccdd80ead20c69f8a536849c9cf8dd3223
parentxen/blkfront: use bdget_disk (diff)
downloadlinux-dev-1d78d7055629e3f6300d6b8d7028259ee2bffc0e.tar.xz
linux-dev-1d78d7055629e3f6300d6b8d7028259ee2bffc0e.zip
xen blkfront: Delay wait for block devices until after the disk is added
When the xen block frontend driver is built as a module the module load is only synchronous up to the point where the frontend and the backend become connected rather than when the disk is added. This means that there can be a race on boot between loading the module and loading the dm-* modules and doing the scan for LVM physical volumes (all in the initrd). In the failure case the disk is not present until after the scan for physical volumes is complete. Taken from: http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/11483a00c017 Signed-off-by: Christian Limpach <Christian.Limpach@xensource.com> Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--drivers/block/xen-blkfront.c11
-rw-r--r--drivers/xen/xenbus/xenbus_probe.c5
-rw-r--r--include/xen/xenbus.h1
3 files changed, 16 insertions, 1 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 4497ff84f64a..dfe61afe676a 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -88,6 +88,7 @@ struct blkfront_info
struct blk_shadow shadow[BLK_RING_SIZE];
unsigned long shadow_free;
int feature_barrier;
+ int is_ready;
/**
* The number of people holding this device open. We won't allow a
@@ -839,6 +840,8 @@ static void blkfront_connect(struct blkfront_info *info)
spin_unlock_irq(&blkif_io_lock);
add_disk(info->gd);
+
+ info->is_ready = 1;
}
/**
@@ -931,6 +934,13 @@ static int blkfront_remove(struct xenbus_device *dev)
return 0;
}
+static int blkfront_is_ready(struct xenbus_device *dev)
+{
+ struct blkfront_info *info = dev->dev.driver_data;
+
+ return info->is_ready;
+}
+
static int blkif_open(struct inode *inode, struct file *filep)
{
struct blkfront_info *info = inode->i_bdev->bd_disk->private_data;
@@ -977,6 +987,7 @@ static struct xenbus_driver blkfront = {
.remove = blkfront_remove,
.resume = blkfront_resume,
.otherend_changed = backend_changed,
+ .is_ready = blkfront_is_ready,
};
static int __init xlblk_init(void)
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 4750de316ad3..88fc5ec665f5 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -846,6 +846,7 @@ static int is_disconnected_device(struct device *dev, void *data)
{
struct xenbus_device *xendev = to_xenbus_device(dev);
struct device_driver *drv = data;
+ struct xenbus_driver *xendrv;
/*
* A device with no driver will never connect. We care only about
@@ -858,7 +859,9 @@ static int is_disconnected_device(struct device *dev, void *data)
if (drv && (dev->driver != drv))
return 0;
- return (xendev->state != XenbusStateConnected);
+ xendrv = to_xenbus_driver(dev->driver);
+ return (xendev->state != XenbusStateConnected ||
+ (xendrv->is_ready && !xendrv->is_ready(xendev)));
}
static int exists_disconnected_device(struct device_driver *drv)
diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index 6f7c290651ae..6369d89c25d5 100644
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -97,6 +97,7 @@ struct xenbus_driver {
int (*uevent)(struct xenbus_device *, char **, int, char *, int);
struct device_driver driver;
int (*read_otherend_details)(struct xenbus_device *dev);
+ int (*is_ready)(struct xenbus_device *dev);
};
static inline struct xenbus_driver *to_xenbus_driver(struct device_driver *drv)