loop: add BLK_DEV_LOOP_MIN_COUNT=%i to allow distros 0 pre-allocated loop devices

[mirror_ubuntu-artful-kernel.git] / drivers / block / loop.c

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 5c9edf944879ae9e58c9f0aaf2ca0324fe7c5272..3defc52f060ca062d361634acd4b7ead29d76350 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1793,21 +1793,6 @@ static int __init loop_init(void)
        struct loop_device *lo;
        int err;
 
-       /*
-        * loop module now has a feature to instantiate underlying device
-        * structure on-demand, provided that there is an access dev node.
-        * However, this will not work well with user space tool that doesn't
-        * know about such "feature".  In order to not break any existing
-        * tool, we do the following:
-        *
-        * (1) if max_loop is specified, create that many upfront, and this
-        *     also becomes a hard limit.
-        * (2) if max_loop is not specified, create 8 loop device on module
-        *     load, user can further extend loop device by create dev node
-        *     themselves and have kernel automatically instantiate actual
-        *     device on-demand.
-        */
-
        err = misc_register(&loop_misc);
        if (err < 0)
                return err;
@@ -1833,11 +1818,19 @@ static int __init loop_init(void)
        if (max_loop > 1UL << (MINORBITS - part_shift))
                return -EINVAL;
 
+       /*
+        * If max_loop is specified, create that many devices upfront.
+        * This also becomes a hard limit. If max_loop is not specified,
+        * create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module
+        * init time. Loop devices can be requested on-demand with the
+        * /dev/loop-control interface, or be instantiated by accessing
+        * a 'dead' device node.
+        */
        if (max_loop) {
                nr = max_loop;
                range = max_loop << part_shift;
        } else {
-               nr = 8;
+               nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT;
                range = 1UL << MINORBITS;
        }
 
@@ -1847,7 +1840,7 @@ static int __init loop_init(void)
        blk_register_region(MKDEV(LOOP_MAJOR, 0), range,
                                  THIS_MODULE, loop_probe, NULL, NULL);
 
-       /* pre-create number devices of devices given by config or max_loop */
+       /* pre-create number of devices given by config or max_loop */
        mutex_lock(&loop_index_mutex);
        for (i = 0; i < nr; i++)
                loop_add(&lo, i);