[PATCH 1/2] mtd: cmdlinepart: allow small partitions

[PATCH 1/2] mtd: cmdlinepart: allow small partitions

[Brian Norris]

I'm not sure why we have a PAGE_SIZE restriction on this partition
parser.

If we really wanted the restriction, I would expect it to be a
restriction for *all* parsers, so we'd move it to the MTD core

At any rate, while small partitions may not be useful (they'll often be
smaller than the eraseblock size and therefore can only be used
read-only), they still have use as a read-only partition.

This restriction is especially annoying because it aborts the entire
MTD's cmdline parsing, leaving it unpartitioned.

So, let's kill the restriction and only check for zero-sized partitions,
which I expect we don't want to allow.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
Anyone know a good reason why this restriction should be here?

 drivers/mtd/cmdlinepart.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/cmdlinepart.c b/drivers/mtd/cmdlinepart.c
index c8503006f17a..477923a8b86f 100644
--- a/drivers/mtd/cmdlinepart.c
+++ b/drivers/mtd/cmdlinepart.c
@@ -115,9 +115,8 @@ static struct mtd_partition * newpart(char *s,
 		s++;
 	} else {
 		size = memparse(s, &s);
-		if (size < PAGE_SIZE) {
-			printk(KERN_ERR ERRP "partition size too small (%llx)\n",
-			       size);
+		if (!size) {
+			printk(KERN_ERR ERRP "partition has size 0\n");
 			return ERR_PTR(-EINVAL);
 		}
 	}
-- 
1.9.1

[PATCH 2/2] mtd: cmdlinepart: convert printk() to pr_*()

[Brian Norris]

This driver uses some custom macros for printing. Let's use the standard
pr_fmt()/pr_{err,warn}().

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
 drivers/mtd/cmdlinepart.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/drivers/mtd/cmdlinepart.c b/drivers/mtd/cmdlinepart.c
index 477923a8b86f..08f62987cc37 100644
--- a/drivers/mtd/cmdlinepart.c
+++ b/drivers/mtd/cmdlinepart.c
@@ -48,6 +48,8 @@
  * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
  */
 
+#define pr_fmt(fmt)	"mtd: " fmt
+
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/mtd/mtd.h>
@@ -55,9 +57,6 @@
 #include <linux/module.h>
 #include <linux/err.h>
 
-/* error message prefix */
-#define ERRP "mtd: "
-
 /* debug macro */
 #if 0
 #define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
@@ -116,7 +115,7 @@ static struct mtd_partition * newpart(char *s,
 	} else {
 		size = memparse(s, &s);
 		if (!size) {
-			printk(KERN_ERR ERRP "partition has size 0\n");
+			pr_err("partition has size 0\n");
 			return ERR_PTR(-EINVAL);
 		}
 	}
@@ -141,7 +140,7 @@ static struct mtd_partition * newpart(char *s,
 		name = ++s;
 		p = strchr(name, delim);
 		if (!p) {
-			printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
+			pr_err("no closing %c found in partition name\n", delim);
 			return ERR_PTR(-EINVAL);
 		}
 		name_len = p - name;
@@ -169,7 +168,7 @@ static struct mtd_partition * newpart(char *s,
 	/* test if more partitions are following */
 	if (*s == ',') {
 		if (size == SIZE_REMAINING) {
-			printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
+			pr_err("no partitions allowed after a fill-up partition\n");
 			return ERR_PTR(-EINVAL);
 		}
 		/* more partitions follow, parse them */
@@ -236,7 +235,7 @@ static int mtdpart_setup_real(char *s)
 		/* fetch <mtd-id> */
 		p = strchr(s, ':');
 		if (!p) {
-			printk(KERN_ERR ERRP "no mtd-id\n");
+			pr_err("no mtd-id\n");
 			return -EINVAL;
 		}
 		mtd_id_len = p - mtd_id;
@@ -288,7 +287,7 @@ static int mtdpart_setup_real(char *s)
 
 		/* does another spec follow? */
 		if (*s != ';') {
-			printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
+			pr_err("bad character after partition (%c)\n", *s);
 			return -EINVAL;
 		}
 		s++;
@@ -342,17 +341,15 @@ static int parse_cmdline_partitions(struct mtd_info *master,
 			part->parts[i].size = master->size - offset;
 
 		if (offset + part->parts[i].size > master->size) {
-			printk(KERN_WARNING ERRP
-			       "%s: partitioning exceeds flash size, truncating\n",
-			       part->mtd_id);
+			pr_warn("%s: partitioning exceeds flash size, truncating\n",
+				part->mtd_id);
 			part->parts[i].size = master->size - offset;
 		}
 		offset += part->parts[i].size;
 
 		if (part->parts[i].size == 0) {
-			printk(KERN_WARNING ERRP
-			       "%s: skipping zero sized partition\n",
-			       part->mtd_id);
+			pr_warn("%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));
-- 
1.9.1

Re: [PATCH 1/2] mtd: cmdlinepart: allow small partitions

[Brian Norris]

On Fri, Jun 19, 2015 at 01:10:06PM -0700, Brian Norris wrote:
> I'm not sure why we have a PAGE_SIZE restriction on this partition
> parser.
> 
> If we really wanted the restriction, I would expect it to be a
> restriction for *all* parsers, so we'd move it to the MTD core
> 
> At any rate, while small partitions may not be useful (they'll often be
> smaller than the eraseblock size and therefore can only be used
> read-only), they still have use as a read-only partition.
> 
> This restriction is especially annoying because it aborts the entire
> MTD's cmdline parsing, leaving it unpartitioned.
> 
> So, let's kill the restriction and only check for zero-sized partitions,
> which I expect we don't want to allow.
> 
> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> ---
> Anyone know a good reason why this restriction should be here?

No comments :)

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