bcache: Use ida for bcache block dev minor

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

1 files changed, 20 insertions, 6 deletions

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index fa1d53087f88..70708ab0b8f9 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -16,6 +16,7 @@
 #include <linux/buffer_head.h>
 #include <linux/debugfs.h>
 #include <linux/genhd.h>
+#include <linux/idr.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
 #include <linux/random.h>
@@ -50,7 +51,8 @@ struct mutex bch_register_lock;
 LIST_HEAD(bch_cache_sets);
 static LIST_HEAD(uncached_devices);
 
-static int bcache_major, bcache_minor;
+static int bcache_major;
+static DEFINE_IDA(bcache_minor);
 static wait_queue_head_t unregister_wait;
 struct workqueue_struct *bcache_wq;
 
@@ -731,8 +733,10 @@ static void bcache_device_free(struct bcache_device *d)
                 del_gendisk(d->disk);
         if (d->disk && d->disk->queue)
                 blk_cleanup_queue(d->disk->queue);
-        if (d->disk)
+        if (d->disk) {
+                ida_simple_remove(&bcache_minor, d->disk->first_minor);
                 put_disk(d->disk);
+        }
 
         bio_split_pool_free(&d->bio_split_hook);
         if (d->unaligned_bvec)
@@ -756,6 +760,7 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
 {
         struct request_queue *q;
         size_t n;
+        int minor;
 
         if (!d->stripe_size)
                 d->stripe_size = 1 << 31;
@@ -783,22 +788,31 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
         if (!d->full_dirty_stripes)
                 return -ENOMEM;
 
+        minor = ida_simple_get(&bcache_minor, 0, MINORMASK + 1, GFP_KERNEL);
+        if (minor < 0)
+                return minor;
+
         if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
             !(d->unaligned_bvec = mempool_create_kmalloc_pool(1,
                                 sizeof(struct bio_vec) * BIO_MAX_PAGES)) ||
             bio_split_pool_init(&d->bio_split_hook) ||
-            !(d->disk = alloc_disk(1)) ||
-            !(q = blk_alloc_queue(GFP_KERNEL)))
+            !(d->disk = alloc_disk(1))) {
+                ida_simple_remove(&bcache_minor, minor);
                 return -ENOMEM;
+        }
 
         set_capacity(d->disk, sectors);
-        snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", bcache_minor);
+        snprintf(d->disk->disk_name, DISK_NAME_LEN, "bcache%i", minor);
 
         d->disk->major          = bcache_major;
-        d->disk->first_minor    = bcache_minor++;
+        d->disk->first_minor    = minor;
         d->disk->fops           = &bcache_ops;
         d->disk->private_data   = d;
 
+        q = blk_alloc_queue(GFP_KERNEL);
+        if (!q)
+                return -ENOMEM;
+
         blk_queue_make_request(q, NULL);
         d->disk->queue                  = q;
         q->queuedata                    = d;