dm: hold DM table for duration of ioctl rather than use blkdev_get

[linux-2.6-microblaze.git] / drivers / md / dm.c

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3b3cbd1..d443818 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -458,67 +458,56 @@ static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
        return dm_get_geometry(md, geo);
 }
 
-static char *_dm_claim_ptr = "I belong to device-mapper";
-
-static int dm_get_bdev_for_ioctl(struct mapped_device *md,
-                                struct block_device **bdev,
-                                fmode_t *mode)
+static int dm_prepare_ioctl(struct mapped_device *md, int *srcu_idx,
+                           struct block_device **bdev, fmode_t *mode)
+       __acquires(md->io_barrier)
 {
        struct dm_target *tgt;
        struct dm_table *map;
-       int srcu_idx, r, r2;
+       int r;
 
 retry:
        r = -ENOTTY;
-       map = dm_get_live_table(md, &srcu_idx);
+       map = dm_get_live_table(md, srcu_idx);
        if (!map || !dm_table_get_size(map))
-               goto out;
+               return r;
 
        /* We only support devices that have a single target */
        if (dm_table_get_num_targets(map) != 1)
-               goto out;
+               return r;
 
        tgt = dm_table_get_target(map, 0);
        if (!tgt->type->prepare_ioctl)
-               goto out;
+               return r;
 
-       if (dm_suspended_md(md)) {
-               r = -EAGAIN;
-               goto out;
-       }
+       if (dm_suspended_md(md))
+               return -EAGAIN;
 
        r = tgt->type->prepare_ioctl(tgt, bdev, mode);
-       if (r < 0)
-               goto out;
-
-       bdgrab(*bdev);
-       r2 = blkdev_get(*bdev, *mode, _dm_claim_ptr);
-       if (r2 < 0) {
-               r = r2;
-               goto out;
-       }
-
-       dm_put_live_table(md, srcu_idx);
-       return r;
-
-out:
-       dm_put_live_table(md, srcu_idx);
        if (r == -ENOTCONN && !fatal_signal_pending(current)) {
+               dm_put_live_table(md, *srcu_idx);
                msleep(10);
                goto retry;
        }
+
        return r;
 }
 
+static void dm_unprepare_ioctl(struct mapped_device *md, int srcu_idx)
+       __releases(md->io_barrier)
+{
+       dm_put_live_table(md, srcu_idx);
+}
+
 static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
                        unsigned int cmd, unsigned long arg)
 {
        struct mapped_device *md = bdev->bd_disk->private_data;
-       int r;
+       int r, srcu_idx;
 
-       r = dm_get_bdev_for_ioctl(md, &bdev, &mode);
+       r = dm_prepare_ioctl(md, &srcu_idx, &bdev, &mode);
        if (r < 0)
-               return r;
+               goto out;
 
        if (r > 0) {
                /*
@@ -536,7 +525,7 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
 
        r =  __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 out:
-       blkdev_put(bdev, mode);
+       dm_unprepare_ioctl(md, srcu_idx);
        return r;
 }
 
@@ -710,6 +699,8 @@ static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
        rcu_read_unlock();
 }
 
+static char *_dm_claim_ptr = "I belong to device-mapper";
+
 /*
  * Open a table device so we can use it as a map destination.
  */
@@ -3044,19 +3035,19 @@ static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
        struct mapped_device *md = bdev->bd_disk->private_data;
        const struct pr_ops *ops;
        fmode_t mode;
-       int r;
+       int r, srcu_idx;
 
-       r = dm_get_bdev_for_ioctl(md, &bdev, &mode);
+       r = dm_prepare_ioctl(md, &srcu_idx, &bdev, &mode);
        if (r < 0)
-               return r;
+               goto out;
 
        ops = bdev->bd_disk->fops->pr_ops;
        if (ops && ops->pr_reserve)
                r = ops->pr_reserve(bdev, key, type, flags);
        else
                r = -EOPNOTSUPP;
-
-       blkdev_put(bdev, mode);
+out:
+       dm_unprepare_ioctl(md, srcu_idx);
        return r;
 }
 
@@ -3065,19 +3056,19 @@ static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
        struct mapped_device *md = bdev->bd_disk->private_data;
        const struct pr_ops *ops;
        fmode_t mode;
-       int r;
+       int r, srcu_idx;
 
-       r = dm_get_bdev_for_ioctl(md, &bdev, &mode);
+       r = dm_prepare_ioctl(md, &srcu_idx, &bdev, &mode);
        if (r < 0)
-               return r;
+               goto out;
 
        ops = bdev->bd_disk->fops->pr_ops;
        if (ops && ops->pr_release)
                r = ops->pr_release(bdev, key, type);
        else
                r = -EOPNOTSUPP;
-
-       blkdev_put(bdev, mode);
+out:
+       dm_unprepare_ioctl(md, srcu_idx);
        return r;
 }
 
@@ -3087,19 +3078,19 @@ static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key,
        struct mapped_device *md = bdev->bd_disk->private_data;
        const struct pr_ops *ops;
        fmode_t mode;
-       int r;
+       int r, srcu_idx;
 
-       r = dm_get_bdev_for_ioctl(md, &bdev, &mode);
+       r = dm_prepare_ioctl(md, &srcu_idx, &bdev, &mode);
        if (r < 0)
-               return r;
+               goto out;
 
        ops = bdev->bd_disk->fops->pr_ops;
        if (ops && ops->pr_preempt)
                r = ops->pr_preempt(bdev, old_key, new_key, type, abort);
        else
                r = -EOPNOTSUPP;
-
-       blkdev_put(bdev, mode);
+out:
+       dm_unprepare_ioctl(md, srcu_idx);
        return r;
 }
 
@@ -3108,19 +3099,19 @@ static int dm_pr_clear(struct block_device *bdev, u64 key)
        struct mapped_device *md = bdev->bd_disk->private_data;
        const struct pr_ops *ops;
        fmode_t mode;
-       int r;
+       int r, srcu_idx;
 
-       r = dm_get_bdev_for_ioctl(md, &bdev, &mode);
+       r = dm_prepare_ioctl(md, &srcu_idx, &bdev, &mode);
        if (r < 0)
-               return r;
+               goto out;
 
        ops = bdev->bd_disk->fops->pr_ops;
        if (ops && ops->pr_clear)
                r = ops->pr_clear(bdev, key);
        else
                r = -EOPNOTSUPP;
-
-       blkdev_put(bdev, mode);
+out:
+       dm_unprepare_ioctl(md, srcu_idx);
        return r;
 }