[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>

[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>
NeilBrown · Linus Torvalds
1 parent d33a56d363
Showing 3 changed files with 18 additions and 28 deletions Side-by-side Diff
drivers/md/md.c
include/linux/raid/md_k.h
init/do_mounts_md.c
@@ -3409,6 +3409,7 @@
  
 	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 @@
 		 * 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);
  
  
@@ -5524,23 +5528,16 @@
  
 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);
 	raid_table_header = register_sysctl_table(raid_root_table, 1);
@@ -5598,8 +5595,8 @@
 	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");
@@ -31,18 +31,15 @@
 #define	LEVEL_NONE		(-1000000)
  
 #define MaxSector (~(sector_t)0)
-#define MD_THREAD_NAME_MAX 14
  
 typedef struct mddev_s mddev_t;
 typedef struct mdk_rdev_s mdk_rdev_t;
  
-#define MAX_MD_DEVS  256	/* Max number of md dev */
-
 /*
  * options passed in raidrun:
  */
  
-/* Currently this must fix in an 'int' */
+/* Currently this must fit in an 'int' */
 #define MAX_CHUNK_SIZE (1<<30)
  
 /*
@@ -20,7 +20,7 @@
 	int level;
 	int chunk;
 	char *device_names;
-} md_setup_args[MAX_MD_DEVS] __initdata;
+} md_setup_args[256] __initdata;
  
 static int md_setup_ents __initdata;
  
@@ -61,10 +61,6 @@
 		return 0;
 	}
 	str1 = str;
-	if (minor >= MAX_MD_DEVS) {
-		printk(KERN_WARNING "md: md=%d, Minor device number too high.\n", minor);
-		return 0;
-	}
 	for (ent=0 ; ent< md_setup_ents ; ent++)
 		if (md_setup_args[ent].minor == minor &&
 		    md_setup_args[ent].partitioned == partitioned) {
@@ -72,7 +68,7 @@
 			       "Replacing previous definition.\n", partitioned?"d":"", minor);
 			break;
 		}
-	if (ent >= MAX_MD_DEVS) {
+	if (ent >= ARRAY_SIZE(md_setup_args)) {
 		printk(KERN_WARNING "md: md=%s%d - too many md initialisations\n", partitioned?"d":"", minor);
 		return 0;
 	}
...	...	@@ -3409,6 +3409,7 @@
3409	3409
3410	3410	printk(KERN_INFO "md: autorun ...\n");
3411	3411	while (!list_empty(&pending_raid_disks)) {
	3412	+ int unit;
3412	3413	dev_t dev;
3413	3414	LIST_HEAD(candidates);
3414	3415	rdev0 = list_entry(pending_raid_disks.next,
3415	3416
...	...	@@ -3428,16 +3429,19 @@
3428	3429	* mostly sane superblocks. It's time to allocate the
3429	3430	* mddev.
3430	3431	*/
3431		- if (rdev0->preferred_minor < 0 \|\| rdev0->preferred_minor >= MAX_MD_DEVS) {
	3432	+ if (part) {
	3433	+ dev = MKDEV(mdp_major,
	3434	+ rdev0->preferred_minor << MdpMinorShift);
	3435	+ unit = MINOR(dev) >> MdpMinorShift;
	3436	+ } else {
	3437	+ dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
	3438	+ unit = MINOR(dev);
	3439	+ }
	3440	+ if (rdev0->preferred_minor != unit) {
3432	3441	printk(KERN_INFO "md: unit number in %s is bad: %d\n",
3433	3442	bdevname(rdev0->bdev, b), rdev0->preferred_minor);
3434	3443	break;
3435	3444	}
3436		- if (part)
3437		- dev = MKDEV(mdp_major,
3438		- rdev0->preferred_minor << MdpMinorShift);
3439		- else
3440		- dev = MKDEV(MD_MAJOR, rdev0->preferred_minor);
3441	3445
3442	3446	md_probe(dev, NULL, NULL);
3443	3447	mddev = mddev_find(dev);
3444	3448
3445	3449
...	...	@@ -5524,23 +5528,16 @@
5524	5528
5525	5529	static int __init md_init(void)
5526	5530	{
5527		- printk(KERN_INFO "md: md driver %d.%d.%d MAX_MD_DEVS=%d,"
5528		- " MD_SB_DISKS=%d\n",
5529		- MD_MAJOR_VERSION, MD_MINOR_VERSION,
5530		- MD_PATCHLEVEL_VERSION, MAX_MD_DEVS, MD_SB_DISKS);
5531		- printk(KERN_INFO "md: bitmap version %d.%d\n", BITMAP_MAJOR_HI,
5532		- BITMAP_MINOR);
5533		-
5534	5531	if (register_blkdev(MAJOR_NR, "md"))
5535	5532	return -1;
5536	5533	if ((mdp_major=register_blkdev(0, "mdp"))<=0) {
5537	5534	unregister_blkdev(MAJOR_NR, "md");
5538	5535	return -1;
5539	5536	}
5540		- blk_register_region(MKDEV(MAJOR_NR, 0), MAX_MD_DEVS, THIS_MODULE,
5541		- md_probe, NULL, NULL);
5542		- blk_register_region(MKDEV(mdp_major, 0), MAX_MD_DEVS<<MdpMinorShift, THIS_MODULE,
	5537	+ blk_register_region(MKDEV(MAJOR_NR, 0), 1UL<<MINORBITS, THIS_MODULE,
5543	5538	md_probe, NULL, NULL);
	5539	+ blk_register_region(MKDEV(mdp_major, 0), 1UL<<MINORBITS, THIS_MODULE,
	5540	+ md_probe, NULL, NULL);
5544	5541
5545	5542	register_reboot_notifier(&md_notifier);
5546	5543	raid_table_header = register_sysctl_table(raid_root_table, 1);
...	...	@@ -5598,8 +5595,8 @@
5598	5595	mddev_t *mddev;
5599	5596	struct list_head *tmp;
5600	5597
5601		- blk_unregister_region(MKDEV(MAJOR_NR,0), MAX_MD_DEVS);
5602		- blk_unregister_region(MKDEV(mdp_major,0), MAX_MD_DEVS << MdpMinorShift);
	5598	+ blk_unregister_region(MKDEV(MAJOR_NR,0), 1U << MINORBITS);
	5599	+ blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
5603	5600
5604	5601	unregister_blkdev(MAJOR_NR,"md");
5605	5602	unregister_blkdev(mdp_major, "mdp");
...	...	@@ -31,18 +31,15 @@
31	31	#define LEVEL_NONE (-1000000)
32	32
33	33	#define MaxSector (~(sector_t)0)
34		-#define MD_THREAD_NAME_MAX 14
35	34
36	35	typedef struct mddev_s mddev_t;
37	36	typedef struct mdk_rdev_s mdk_rdev_t;
38	37
39		-#define MAX_MD_DEVS 256 /* Max number of md dev */
40		-
41	38	/*
42	39	* options passed in raidrun:
43	40	*/
44	41
45		-/* Currently this must fix in an 'int' */
	42	+/* Currently this must fit in an 'int' */
46	43	#define MAX_CHUNK_SIZE (1<<30)
47	44
48	45	/*
...	...	@@ -20,7 +20,7 @@
20	20	int level;
21	21	int chunk;
22	22	char *device_names;
23		-} md_setup_args[MAX_MD_DEVS] __initdata;
	23	+} md_setup_args[256] __initdata;
24	24
25	25	static int md_setup_ents __initdata;
26	26
...	...	@@ -61,10 +61,6 @@
61	61	return 0;
62	62	}
63	63	str1 = str;
64		- if (minor >= MAX_MD_DEVS) {
65		- printk(KERN_WARNING "md: md=%d, Minor device number too high.\n", minor);
66		- return 0;
67		- }
68	64	for (ent=0 ; ent< md_setup_ents ; ent++)
69	65	if (md_setup_args[ent].minor == minor &&
70	66	md_setup_args[ent].partitioned == partitioned) {
...	...	@@ -72,7 +68,7 @@
72	68	"Replacing previous definition.\n", partitioned?"d":"", minor);
73	69	break;
74	70	}
75		- if (ent >= MAX_MD_DEVS) {
	71	+ if (ent >= ARRAY_SIZE(md_setup_args)) {
76	72	printk(KERN_WARNING "md: md=%s%d - too many md initialisations\n", partitioned?"d":"", minor);
77	73	return 0;
78	74	}