[PATCH] mtd cmdlinepart: allow zero offset value

Current cmdlinepart.c uses offset value 0 to specify a continuous
partition.  This prevents creating a second partition starting at 0.

For example, I can split 4MB device using "mtdparts=id:2M,2M", but I can
not do "mtdparts=id:2M@2M,2M@0" to swap mtd0 and mtd1.

This patch introduces special OFFSET_CONTINUOUS value for a continuous
partition and allows 0 for offset value.

Also this patch replaces 0xffffffff with UINT_MAX for SIZE_REMAINING.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/mtd/cmdlinepart.c b/drivers/mtd/cmdlinepart.c
index 6b8bb2e4dcf..a7a7bfe3387 100644
--- a/drivers/mtd/cmdlinepart.c
+++ b/drivers/mtd/cmdlinepart.c
@@ -42,7 +42,8 @@
 
 
 /* special size referring to all the remaining space in a partition */
-#define SIZE_REMAINING 0xffffffff
+#define SIZE_REMAINING UINT_MAX
+#define OFFSET_CONTINUOUS UINT_MAX
 
 struct cmdline_mtd_partition {
         struct cmdline_mtd_partition *next;
@@ -75,7 +76,7 @@ static struct mtd_partition * newpart(char *s,
 {
         struct mtd_partition *parts;
         unsigned long size;
-        unsigned long offset = 0;
+        unsigned long offset = OFFSET_CONTINUOUS;
         char *name;
         int name_len;
         unsigned char *extra_mem;
@@ -314,7 +315,7 @@ static int parse_cmdline_partitions(struct mtd_info *master,
                 {
                         for(i = 0, offset = 0; i < part->num_parts; i++)
                         {
-                                if (!part->parts[i].offset)
+                                if (part->parts[i].offset == OFFSET_CONTINUOUS)
                                   part->parts[i].offset = offset;
                                 else
                                   offset = part->parts[i].offset;