[PATCH] md: remove MAX_MD_DEVS which is an arbitrary limit

Once upon a time we needed to fixed limit to the number of md devices,
probably because we preallocated some array.  This need no longer exists, but
we still have an arbitrary limit.

So remove MAX_MD_DEVS and allow as many devices as we can fit into the 'minor'
part of a device number.

Also remove some useless noise at init time (which reports MAX_MD_DEVS) and
remove MD_THREAD_NAME_MAX which hasn't been used for a while.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 15 insertions, 18 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index db1ac84a739a..40cb79ac4039 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3409,6 +3409,7 @@ static void autorun_devices(int part)
 
         printk(KERN_INFO "md: autorun ...\n");
         while (!list_empty(&pending_raid_disks)) {
+                int unit;
                 dev_t dev;
                 LIST_HEAD(candidates);
                 rdev0 = list_entry(pending_raid_disks.next,
@@ -3428,16 +3429,19 @@ static void autorun_devices(int part)
                  * mostly sane superblocks. It's time to allocate the
                  * mddev.
                  */
-                if (rdev0->preferred_minor < 0 || rdev0->preferred_minor >= MAX_MD_DEVS) {
+                if (part) {
+                        dev = MKDEV(mdp_major,
+                                    rdev0->preferred_minor << MdpMinorShift);
+                        unit = MINOR(dev) >> MdpMinorShift;
+                } else {
+                        dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
+                        unit = MINOR(dev);
+                }
+                if (rdev0->preferred_minor != unit) {
                         printk(KERN_INFO "md: unit number in %s is bad: %d\n",
                                bdevname(rdev0->bdev, b), rdev0->preferred_minor);
                         break;
                 }
-                if (part)
-                        dev = MKDEV(mdp_major,
-                                    rdev0->preferred_minor << MdpMinorShift);
-                else
-                        dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
 
                 md_probe(dev, NULL, NULL);
                 mddev = mddev_find(dev);
@@ -5524,22 +5528,15 @@ static void md_geninit(void)
 
 static int __init md_init(void)
 {
-        printk(KERN_INFO "md: md driver %d.%d.%d MAX_MD_DEVS=%d,"
-                        " MD_SB_DISKS=%d\n",
-                        MD_MAJOR_VERSION, MD_MINOR_VERSION,
-                        MD_PATCHLEVEL_VERSION, MAX_MD_DEVS, MD_SB_DISKS);
-        printk(KERN_INFO "md: bitmap version %d.%d\n", BITMAP_MAJOR_HI,
-                        BITMAP_MINOR);
-
         if (register_blkdev(MAJOR_NR, "md"))
                 return -1;
         if ((mdp_major=register_blkdev(0, "mdp"))<=0) {
                 unregister_blkdev(MAJOR_NR, "md");
                 return -1;
         }
-        blk_register_region(MKDEV(MAJOR_NR, 0), MAX_MD_DEVS, THIS_MODULE,
-                                md_probe, NULL, NULL);
-        blk_register_region(MKDEV(mdp_major, 0), MAX_MD_DEVS<<MdpMinorShift, THIS_MODULE,
+        blk_register_region(MKDEV(MAJOR_NR, 0), 1UL<<MINORBITS, THIS_MODULE,
+                            md_probe, NULL, NULL);
+        blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
                             md_probe, NULL, NULL);
 
         register_reboot_notifier(&md_notifier);
@@ -5598,8 +5595,8 @@ static __exit void md_exit(void)
         mddev_t *mddev;
         struct list_head *tmp;
 
-        blk_unregister_region(MKDEV(MAJOR_NR,0), MAX_MD_DEVS);
-        blk_unregister_region(MKDEV(mdp_major,0), MAX_MD_DEVS << MdpMinorShift);
+        blk_unregister_region(MKDEV(MAJOR_NR,0), 1U << MINORBITS);
+        blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
 
         unregister_blkdev(MAJOR_NR,"md");
         unregister_blkdev(mdp_major, "mdp");