From 63152c1b330f75842644c82d925fa8dcd37fe233 Mon Sep 17 00:00:00 2001
From: Neil Brown <neilb@suse.de>
Date: Mon, 5 May 2008 21:55:36 +1000
Subject: [PATCH] Unify code into find_free_devnum.

Two places have code to find a free md device number.  Make this
a subroutine.
---
 Incremental.c | 15 +++++----------
 mdadm.h       |  3 +++
 mdopen.c      | 36 +++++-------------------------------
 util.c        | 37 +++++++++++++++++++++++++++++++++++++
 4 files changed, 50 insertions(+), 41 deletions(-)

diff --git a/Incremental.c b/Incremental.c
index 4c6a2a79..b54c4fc5 100644
--- a/Incremental.c
+++ b/Incremental.c
@@ -246,20 +246,15 @@ int Incremental(char *devname, int verbose, int runstop,
 
 		if (devnum < 0) {
 			/* Haven't found anything yet, choose something free */
-			/* There is similar code in mdopen.c - should unify */
-			for (devnum = 127 ; devnum != 128 ;
-			     devnum = devnum ? devnum-1 : (1<<22)-1) {
-				if (mddev_busy(use_partitions ?
-					       (-1-devnum) : devnum))
-					break;
-			}
-			if (devnum == 128) {
+			devnum = find_free_devnum(use_partitions);
+
+			if (devnum == NoMdDev) {
 				fprintf(stderr, Name
 					": No spare md devices!!\n");
 				return 2;
 			}
-		}
-		devnum = use_partitions ? (-1-devnum) : devnum;
+		} else
+			devnum = use_partitions ? (-1-devnum) : devnum;
 	}
 	mdfd = open_mddev_devnum(match ? match->devname : NULL,
 				 devnum,
diff --git a/mdadm.h b/mdadm.h
index 2a5e1c8c..2f62c41d 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -513,6 +513,9 @@ extern void remove_partitions(int fd);
 extern char *human_size(long long bytes);
 char *human_size_brief(long long bytes);
 
+#define NoMdDev (1<<23)
+extern int find_free_devnum(int use_partitions);
+
 extern void put_md_name(char *name);
 extern char *get_md_name(int dev);
 
diff --git a/mdopen.c b/mdopen.c
index 7f6a2ea4..fe983708 100644
--- a/mdopen.c
+++ b/mdopen.c
@@ -113,7 +113,6 @@ int open_mddev(char *dev, int autof)
 	int major_num = MD_MAJOR;
 	int minor_num = 0;
 	int must_remove = 0;
-	struct mdstat_ent *mdlist;
 	int num;
 	struct createinfo *ci = conf_get_create_info();
 	int parts;
@@ -197,37 +196,12 @@ int open_mddev(char *dev, int autof)
 		 */
 		if (num < 0) {
 			/* need to pick an unused number */
-			mdlist = mdstat_read(0, 0);
-			/* Choose a large number.  Start from 127 and search down,
-			 * but if nothing is found, start really big
-			 */
-			for (num = 127 ; num != 128 ; num = num ? num-1 : (1<<22)-1) {
-				struct mdstat_ent *me;
-				int devnum = num;
-				if (major_num != MD_MAJOR)
-					devnum = -1-num;
+			int num = find_free_devnum(major_num != MD_MAJOR);
 
-				for (me=mdlist; me; me=me->next)
-					if (me->devnum == devnum)
-						break;
-				if (!me) {
-					/* doesn't exist in mdstat.
-					 * make sure it is new to /dev too
-					 */
-					char *dn;
-					if (major_num != MD_MAJOR)
-						minor_num = num << MdpMinorShift;
-					else
-						minor_num = num;
-					dn = map_dev(major_num,minor_num, 0);
-					if (dn==NULL || is_standard(dn, NULL)) {
-						/* this number only used by a 'standard' name,
-						 * so it is safe to use
-						 */
-						break;
-					}
-				}
-			}
+			if (major_num == MD_MAJOR)
+				minor_num = num;
+			else
+				minor_num = (-1-num) << MdpMinorShift;
 		} else if (major_num == MD_MAJOR)
 			minor_num = num;
 		else
diff --git a/util.c b/util.c
index dbe46404..514b7139 100644
--- a/util.c
+++ b/util.c
@@ -862,6 +862,43 @@ void get_one_disk(int mdfd, mdu_array_info_t *ainf, mdu_disk_info_t *disk)
 		if (ioctl(mdfd, GET_DISK_INFO, disk) == 0)
 			return;
 }
+
+static int dev2major(int d)
+{
+	if (d >= 0)
+		return MD_MAJOR;
+	else
+		return get_mdp_major();
+}
+
+static int dev2minor(int d)
+{
+	if (d >= 0)
+		return d;
+	return (-1-d) << MdpMinorShift;
+}
+
+int find_free_devnum(int use_partitions)
+{
+	int devnum;
+	for (devnum = 127; devnum != 128;
+	     devnum = devnum ? devnum-1 : (1<<22)-1) {
+		char *dn;
+		if (mddev_busy(use_partitions ? (-1-devnum) : devnum))
+			continue;
+		/* make sure it is new to /dev too, at least as a
+		 * non-standard */
+		dn = map_dev(dev2major(devnum), dev2minor(devnum), 0);
+		if (dn && ! is_standard(dn, NULL))
+			continue;
+		break;
+	}
+	if (devnum == 128)
+		return NoMdDev;
+	return use_partitions ? (-1-devnum) : devnum;
+}
+
+
 #ifdef __TINYC__
 /* tinyc doesn't optimize this check in ioctl.h out ... */
 unsigned int __invalid_size_argument_for_IOC = 0;
-- 
2.39.2