dm: convert to idr_alloc()

Convert to the much saner new idr interface.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alasdair Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 15 insertions, 39 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 9ffa7467d270..e67a4be0080d 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1755,62 +1755,38 @@ static void free_minor(int minor)
  */
 static int specific_minor(int minor)
 {
-        int r, m;
+        int r;
 
         if (minor >= (1 << MINORBITS))
                 return -EINVAL;
 
-        r = idr_pre_get(&_minor_idr, GFP_KERNEL);
-        if (!r)
-                return -ENOMEM;
-
+        idr_preload(GFP_KERNEL);
         spin_lock(&_minor_lock);
 
-        if (idr_find(&_minor_idr, minor)) {
-                r = -EBUSY;
-                goto out;
-        }
-
-        r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
-        if (r)
-                goto out;
+        r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
 
-        if (m != minor) {
-                idr_remove(&_minor_idr, m);
-                r = -EBUSY;
-                goto out;
-        }
-
-out:
         spin_unlock(&_minor_lock);
-        return r;
+        idr_preload_end();
+        if (r < 0)
+                return r == -ENOSPC ? -EBUSY : r;
+        return 0;
 }
 
 static int next_free_minor(int *minor)
 {
-        int r, m;
-
-        r = idr_pre_get(&_minor_idr, GFP_KERNEL);
-        if (!r)
-                return -ENOMEM;
+        int r;
 
+        idr_preload(GFP_KERNEL);
         spin_lock(&_minor_lock);
 
-        r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
-        if (r)
-                goto out;
-
-        if (m >= (1 << MINORBITS)) {
-                idr_remove(&_minor_idr, m);
-                r = -ENOSPC;
-                goto out;
-        }
-
-        *minor = m;
+        r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
 
-out:
         spin_unlock(&_minor_lock);
-        return r;
+        idr_preload_end();
+        if (r < 0)
+                return r;
+        *minor = r;
+        return 0;
 }
 
 static const struct block_device_operations dm_blk_dops;