block: make gendisk hold a reference to its queue

[pandora-kernel.git] / fs / block_dev.c

diff --git a/fs/block_dev.c b/fs/block_dev.c
index ff77262..1c44b8d 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1085,6 +1085,7 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
 static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 {
        struct gendisk *disk;
+       struct module *owner;
        int ret;
        int partno;
        int perm = 0;
@@ -1110,6 +1111,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
        disk = get_gendisk(bdev->bd_dev, &partno);
        if (!disk)
                goto out;
+       owner = disk->fops->owner;
 
        disk_block_events(disk);
        mutex_lock_nested(&bdev->bd_mutex, for_part);
@@ -1137,8 +1139,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                                        bdev->bd_disk = NULL;
                                        mutex_unlock(&bdev->bd_mutex);
                                        disk_unblock_events(disk);
-                                       module_put(disk->fops->owner);
                                        put_disk(disk);
+                                       module_put(owner);
                                        goto restart;
                                }
                        }
@@ -1194,8 +1196,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
                                goto out_unlock_bdev;
                }
                /* only one opener holds refs to the module and disk */
-               module_put(disk->fops->owner);
                put_disk(disk);
+               module_put(owner);
        }
        bdev->bd_openers++;
        if (for_part)
@@ -1215,8 +1217,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
  out_unlock_bdev:
        mutex_unlock(&bdev->bd_mutex);
        disk_unblock_events(disk);
-       module_put(disk->fops->owner);
        put_disk(disk);
+       module_put(owner);
  out:
        bdput(bdev);
 
@@ -1429,6 +1431,11 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
                WARN_ON_ONCE(bdev->bd_holders);
                sync_blockdev(bdev);
                kill_bdev(bdev);
+               /* ->release can cause the old bdi to disappear,
+                * so must switch it out first
+                */
+               bdev_inode_switch_bdi(bdev->bd_inode,
+                                       &default_backing_dev_info);
        }
        if (bdev->bd_contains == bdev) {
                if (disk->fops->release)
@@ -1437,16 +1444,15 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
        if (!bdev->bd_openers) {
                struct module *owner = disk->fops->owner;
 
-               put_disk(disk);
-               module_put(owner);
                disk_put_part(bdev->bd_part);
                bdev->bd_part = NULL;
                bdev->bd_disk = NULL;
-               bdev_inode_switch_bdi(bdev->bd_inode,
-                                       &default_backing_dev_info);
                if (bdev != bdev->bd_contains)
                        victim = bdev->bd_contains;
                bdev->bd_contains = NULL;
+
+               put_disk(disk);
+               module_put(owner);
        }
        mutex_unlock(&bdev->bd_mutex);
        bdput(bdev);