1 files changed, 41 insertions, 8 deletions

diff --git a/block/bsg.c b/block/bsg.c
index cd0221c61bfe..4ef3cc550244 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -58,6 +58,7 @@ enum {
 };
 
 #define BSG_DEFAULT_CMDS        64
+#define BSG_MAX_DEVS            32768
 
 #undef BSG_DEBUG
 
@@ -75,7 +76,7 @@ enum {
 #define BSG_MAJOR       (240)
 
 static DEFINE_MUTEX(bsg_mutex);
-static int bsg_device_nr;
+static int bsg_device_nr, bsg_minor_idx;
 
 #define BSG_LIST_SIZE   (8)
 #define bsg_list_idx(minor)     ((minor) & (BSG_LIST_SIZE - 1))
@@ -957,14 +958,15 @@ void bsg_unregister_queue(struct request_queue *q)
         class_device_destroy(bsg_class, MKDEV(BSG_MAJOR, bcd->minor));
         bcd->class_dev = NULL;
         list_del_init(&bcd->list);
+        bsg_device_nr--;
         mutex_unlock(&bsg_mutex);
 }
 
 int bsg_register_queue(struct request_queue *q, char *name)
 {
-        struct bsg_class_device *bcd;
+        struct bsg_class_device *bcd, *__bcd;
         dev_t dev;
-        int ret;
+        int ret = -EMFILE;
         struct class_device *class_dev = NULL;
 
         /*
@@ -978,10 +980,27 @@ int bsg_register_queue(struct request_queue *q, char *name)
         INIT_LIST_HEAD(&bcd->list);
 
         mutex_lock(&bsg_mutex);
-        dev = MKDEV(BSG_MAJOR, bsg_device_nr);
-        bcd->minor = bsg_device_nr;
-        bsg_device_nr++;
+        if (bsg_device_nr == BSG_MAX_DEVS) {
+                printk(KERN_ERR "bsg: too many bsg devices\n");
+                goto err;
+        }
+
+retry:
+        list_for_each_entry(__bcd, &bsg_class_list, list) {
+                if (__bcd->minor == bsg_minor_idx) {
+                        bsg_minor_idx++;
+                        if (bsg_minor_idx == BSG_MAX_DEVS)
+                                bsg_minor_idx = 0;
+                        goto retry;
+                }
+        }
+
+        bcd->minor = bsg_minor_idx++;
+        if (bsg_minor_idx == BSG_MAX_DEVS)
+                bsg_minor_idx = 0;
+
         bcd->queue = q;
+        dev = MKDEV(BSG_MAJOR, bcd->minor);
         class_dev = class_device_create(bsg_class, NULL, dev, bcd->dev, "%s", name);
         if (IS_ERR(class_dev)) {
                 ret = PTR_ERR(class_dev);
@@ -996,11 +1015,11 @@ int bsg_register_queue(struct request_queue *q, char *name)
         }
 
         list_add_tail(&bcd->list, &bsg_class_list);
+        bsg_device_nr++;
 
         mutex_unlock(&bsg_mutex);
         return 0;
 err:
-        bsg_device_nr--;
         if (class_dev)
                 class_device_destroy(bsg_class, MKDEV(BSG_MAJOR, bcd->minor));
         mutex_unlock(&bsg_mutex);
@@ -1030,6 +1049,11 @@ static struct class_interface bsg_intf = {
         .remove = bsg_remove,
 };
 
+static struct cdev bsg_cdev = {
+        .kobj   = {.name = "bsg", },
+        .owner  = THIS_MODULE,
+};
+
 static int __init bsg_init(void)
 {
         int ret, i;
@@ -1050,10 +1074,19 @@ static int __init bsg_init(void)
                 return PTR_ERR(bsg_class);
         }
 
-        ret = register_chrdev(BSG_MAJOR, "bsg", &bsg_fops);
+        ret = register_chrdev_region(MKDEV(BSG_MAJOR, 0), BSG_MAX_DEVS, "bsg");
+        if (ret) {
+                kmem_cache_destroy(bsg_cmd_cachep);
+                class_destroy(bsg_class);
+                return ret;
+        }
+
+        cdev_init(&bsg_cdev, &bsg_fops);
+        ret = cdev_add(&bsg_cdev, MKDEV(BSG_MAJOR, 0), BSG_MAX_DEVS);
         if (ret) {
                 kmem_cache_destroy(bsg_cmd_cachep);
                 class_destroy(bsg_class);
+                unregister_chrdev_region(MKDEV(BSG_MAJOR, 0), BSG_MAX_DEVS);
                 return ret;
         }