block: convert to idr_alloc()

Convert to the much saner new idr interface.  Both bsg and genhd
protect idr w/ mutex making preloading unnecessary.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 15 deletions

diff --git a/block/genhd.c b/block/genhd.c
index 841b3037d866..3c001fba80c7 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -411,7 +411,7 @@ static int blk_mangle_minor(int minor)
 int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
 {
         struct gendisk *disk = part_to_disk(part);
-        int idx, rc;
+        int idx;
 
         /* in consecutive minor range? */
         if (part->partno < disk->minors) {
@@ -420,20 +420,11 @@ int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
         }
 
         /* allocate ext devt */
-        do {
-                if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL))
-                        return -ENOMEM;
-                mutex_lock(&ext_devt_mutex);
-                rc = idr_get_new(&ext_devt_idr, part, &idx);
-                if (!rc && idx >= NR_EXT_DEVT) {
-                        idr_remove(&ext_devt_idr, idx);
-                        rc = -EBUSY;
-                }
-                mutex_unlock(&ext_devt_mutex);
-        } while (rc == -EAGAIN);
-
-        if (rc)
-                return rc;
+        mutex_lock(&ext_devt_mutex);
+        idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_KERNEL);
+        mutex_unlock(&ext_devt_mutex);
+        if (idx < 0)
+                return idx == -ENOSPC ? -EBUSY : idx;
 
         *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
         return 0;