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>

2 files changed, 15 insertions, 32 deletions

diff --git a/block/bsg.c b/block/bsg.c
index ff64ae3bacee..3ca92ebf6bbb 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -997,7 +997,7 @@ int bsg_register_queue(struct request_queue *q, struct device *parent,
 {
         struct bsg_class_device *bcd;
         dev_t dev;
-        int ret, minor;
+        int ret;
         struct device *class_dev = NULL;
         const char *devname;
 
@@ -1017,23 +1017,16 @@ int bsg_register_queue(struct request_queue *q, struct device *parent,
 
         mutex_lock(&bsg_mutex);
 
-        ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL);
-        if (!ret) {
-                ret = -ENOMEM;
-                goto unlock;
-        }
-
-        ret = idr_get_new(&bsg_minor_idr, bcd, &minor);
-        if (ret < 0)
+        ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
+        if (ret < 0) {
+                if (ret == -ENOSPC) {
+                        printk(KERN_ERR "bsg: too many bsg devices\n");
+                        ret = -EINVAL;
+                }
                 goto unlock;
-
-        if (minor >= BSG_MAX_DEVS) {
-                printk(KERN_ERR "bsg: too many bsg devices\n");
-                ret = -EINVAL;
-                goto remove_idr;
         }
 
-        bcd->minor = minor;
+        bcd->minor = ret;
         bcd->queue = q;
         bcd->parent = get_device(parent);
         bcd->release = release;
@@ -1059,8 +1052,7 @@ unregister_class_dev:
         device_unregister(class_dev);
 put_dev:
         put_device(parent);
-remove_idr:
-        idr_remove(&bsg_minor_idr, minor);
+        idr_remove(&bsg_minor_idr, bcd->minor);
 unlock:
         mutex_unlock(&bsg_mutex);
         return ret;
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;