mtd: cmdlinepart: make the partitions rule more strict

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=7baf04261062826ea225ab23e07c541e279143fa
Commit:     7baf04261062826ea225ab23e07c541e279143fa
Parent:     2fe87aef33b77d66fada83f5dc57b6798ad5df07
Author:     Shmulik Ladkani <shmulik.ladkani at gmail.com>
AuthorDate: Wed Sep 5 08:30:20 2012 +0300
Committer:  David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Sat Sep 29 15:44:25 2012 +0100

    mtd: cmdlinepart: make the partitions rule more strict
    
    Huang Shijie <shijie8 at gmail.com> explains:
    
    Assume we have a 1GiB(8Gib) NAND chip, and we set the partitions
    in the command line like this:
        #gpmi-nand:100m(boot),100m(kernel),1g(rootfs)
    
    In this case, the partition truncating occurs. The current code will
    get the following result:
    
         ----------------------------------
            root at freescale ~$ cat /proc/mtd
            dev:    size   erasesize  name
            mtd0: 06400000 00040000 "boot"
            mtd1: 06400000 00040000 "kernel"
         ----------------------------------
    
    It is obvious that we lost the truncated partition `rootfs` which should
    be 824MiB in this case.
    
    Also, forbid 0-sized partitions.
    
    Signed-off-by: Shmulik Ladkani <shmulik.ladkani at gmail.com>
    Signed-off-by: Artem Bityutskiy <artem.bityutskiy at linux.intel.com>
    Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
 drivers/mtd/cmdlinepart.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/mtd/cmdlinepart.c b/drivers/mtd/cmdlinepart.c
index 17b0bd4..aed1b8a 100644
--- a/drivers/mtd/cmdlinepart.c
+++ b/drivers/mtd/cmdlinepart.c
@@ -319,12 +319,22 @@ static int parse_cmdline_partitions(struct mtd_info *master,
 				if (part->parts[i].size == SIZE_REMAINING)
 					part->parts[i].size = master->size - offset;
 
+				if (part->parts[i].size == 0) {
+					printk(KERN_WARNING ERRP
+					       "%s: skipping zero sized partition\n",
+					       part->mtd_id);
+					part->num_parts--;
+					memmove(&part->parts[i],
+						&part->parts[i + 1],
+						sizeof(*part->parts) * (part->num_parts - i));
+					continue;
+				}
+
 				if (offset + part->parts[i].size > master->size) {
 					printk(KERN_WARNING ERRP
 					       "%s: partitioning exceeds flash size, truncating\n",
 					       part->mtd_id);
 					part->parts[i].size = master->size - offset;
-					part->num_parts = i;
 				}
 				offset += part->parts[i].size;
 			}