Patchwork [v2,3/3] mtd: cmdlinepart: check the partitions

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Submitter Huang Shijie
Date Sept. 4, 2012, 7:43 a.m.
Message ID <1346744628-13840-3-git-send-email-b32955@freescale.com>
Download mbox | patch
Permalink /patch/181516/
State New
Headers show

Comments

Huang Shijie - Sept. 4, 2012, 7:43 a.m.
The partitions are all sorted well by the @offset.
But we should check if there are errors in the partitions.

The following cases are regarded as errors:
  [1] There is a hole in the partitions, such as
      #gpmi-nand:100m(boot),100m@100m(kernel),1g@200m(rootfs)

  [2] There is a overlap in the partitions, such as
      #gpmi-nand:100m@0(boot),100m@50m(kernel),1g@150m(rootfs)

  [3] Not all the partitions are set with @offset, and there are
      more then one partion whose offset is OFFSET_CONTINUOUS.
      #gpmi-nand:100m@0(boot),100m(kernel),-(usr)

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
 drivers/mtd/cmdlinepart.c |   82 ++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 77 insertions(+), 5 deletions(-)
Artem Bityutskiy - Sept. 4, 2012, 8:19 a.m.
On Tue, 2012-09-04 at 15:43 +0800, Huang Shijie wrote:
> +enum partition_check_result {
> +	PARTITION_GOOD,
> +	PARTITION_OVERLAPPED,
> +	PARTITION_HOLE,
> +	PARTITION_TOO_MUCH_CONT,
> +};

Could you please kill these constants, they are not really needed I
think.

> +/* The partitions have been sorted well by the @offset. */
> +static inline int check_partitions(struct mtd_partition *parts, int num_parts)
> +{
> +	int i;
> +	uint64_t offset = 0;
> +	int offset_continuous_cnt = 0;
> +
> +	for (i = 0; i < num_parts; i++) {
> +		if (parts[i].offset == OFFSET_CONTINUOUS) {
> +			offset_continuous_cnt++;
> +			continue;
> +		}
> +
> +		/* find a hole. */
> +		if (parts[i].offset > offset)
> +			return PARTITION_HOLE;

Just print the error messages in this function and return -EINVAL.


> @@ -285,13 +333,37 @@ static int mtdpart_setup_real(char *s)
>  		/* sort the partitions */
>  		sort_partitons(parts, num_parts);
>  
> -		/* link into chain */
> -		this_mtd->next = partitions;
> -		partitions = this_mtd;
> +		/* check the partitions */
> +		ret = check_partitions(parts, num_parts);

Just do

if (ret)
	return ret;


and kill the huge 'switch' that you added.
Huang Shijie - Sept. 4, 2012, 8:25 a.m.
于 2012年09月04日 16:19, Artem Bityutskiy 写道:
> Just do
>
> if (ret)
> 	return ret;
>
>
> and kill the huge 'switch' that you added.
If the cmdline have two mtd-ids such as:
   
gpmi-nand:100m(root),100m@100m(kernel),1g@200m(rootfs);edb7212-nand:-(home)

The `return` will also bypass the `edb7212-nand`.

Is it acceptable?

Best Regards
Huang Shijie
Artem Bityutskiy - Sept. 4, 2012, 8:50 a.m.
On Tue, 2012-09-04 at 16:25 +0800, Huang Shijie wrote:
> 于 2012年09月04日 16:19, Artem Bityutskiy 写道:
> > Just do
> >
> > if (ret)
> > 	return ret;
> >
> >
> > and kill the huge 'switch' that you added.
> If the cmdline have two mtd-ids such as:
>    
> gpmi-nand:100m(root),100m@100m(kernel),1g@200m(rootfs);edb7212-nand:-(home)
> 
> The `return` will also bypass the `edb7212-nand`.
> 
> Is it acceptable?

I thought the whole idea is to refuse command lines which are ambiguous
or make no sense, no?

You could actually do this in two step and split your 3rd patch:

1. Add 'check_partitions' which prints an error messages and returns
-EINVAL if the command line has overlaps or gaps or other bad things.
But ignore the return code in 'mtdpart_setup_real()'

2. Make 'mtdpart_setup_real()' check for the error code and propagate it
up, so we'll have a prink + real refusal.

Patch

diff --git a/drivers/mtd/cmdlinepart.c b/drivers/mtd/cmdlinepart.c
index edd17e0..3473af5 100644
--- a/drivers/mtd/cmdlinepart.c
+++ b/drivers/mtd/cmdlinepart.c
@@ -225,6 +225,53 @@  static inline void sort_partitons(struct mtd_partition *parts, int num_parts)
 	return;
 }
 
+enum partition_check_result {
+	PARTITION_GOOD,
+	PARTITION_OVERLAPPED,
+	PARTITION_HOLE,
+	PARTITION_TOO_MUCH_CONT,
+};
+
+/* The partitions have been sorted well by the @offset. */
+static inline int check_partitions(struct mtd_partition *parts, int num_parts)
+{
+	int i;
+	uint64_t offset = 0;
+	int offset_continuous_cnt = 0;
+
+	for (i = 0; i < num_parts; i++) {
+		if (parts[i].offset == OFFSET_CONTINUOUS) {
+			offset_continuous_cnt++;
+			continue;
+		}
+
+		/* find a hole. */
+		if (parts[i].offset > offset)
+			return PARTITION_HOLE;
+
+		/* find an overlapped partition. */
+		if (parts[i].offset < offset)
+			return PARTITION_OVERLAPPED;
+
+		offset += parts[i].size;
+	}
+
+	if (offset_continuous_cnt) {
+		/* We do not set partitions with the @offset in the cmdline. */
+		if (offset_continuous_cnt == num_parts)
+			return PARTITION_GOOD;
+
+		/* It's ok if there is only one OFFSET_CONTINUOUS partition. */
+		if (offset_continuous_cnt == 1)
+			return PARTITION_GOOD;
+
+		return PARTITION_TOO_MUCH_CONT;
+	}
+
+	/* We set with @offset for all the partitions in the cmdline. */
+	return PARTITION_GOOD;
+}
+
 /*
  * Parse the command line.
  */
@@ -238,6 +285,7 @@  static int mtdpart_setup_real(char *s)
 		struct mtd_partition *parts;
 		int mtd_id_len, num_parts;
 		char *p, *mtd_id;
+		enum partition_check_result ret;
 
 		mtd_id = s;
 
@@ -285,13 +333,37 @@  static int mtdpart_setup_real(char *s)
 		/* sort the partitions */
 		sort_partitons(parts, num_parts);
 
-		/* link into chain */
-		this_mtd->next = partitions;
-		partitions = this_mtd;
+		/* check the partitions */
+		ret = check_partitions(parts, num_parts);
+		switch (ret) {
+		case PARTITION_GOOD:
+			/* link into chain */
+			this_mtd->next = partitions;
+			partitions = this_mtd;
 
-		dbg(("mtdid=<%s> num_parts=<%d>\n",
-		     this_mtd->mtd_id, this_mtd->num_parts));
+			dbg(("mtdid=<%s> num_parts=<%d>\n",
+			     this_mtd->mtd_id, this_mtd->num_parts));
+			break;
 
+		case PARTITION_OVERLAPPED:
+			printk(KERN_ERR ERRP "%s:The partitions overlap,"
+				"please check the cmdline, and fix it.\n",
+				this_mtd->mtd_id);
+			break;
+
+		case PARTITION_HOLE:
+			printk(KERN_ERR ERRP "%s:There is a hole in the "
+				"partitions, please check the cmdline, "
+				"and fix it.\n",
+				this_mtd->mtd_id);
+			break;
+
+		case PARTITION_TOO_MUCH_CONT:
+			printk(KERN_ERR ERRP "%s:The offset is not right,"
+				"please check the cmdline, and fix it.\n",
+				this_mtd->mtd_id);
+			break;
+		}
 
 		/* EOS - we're done */
 		if (*s == 0)