[PATCH v2] mtd: Fix partition alignment check on multi-erasesize devices

[PATCH v2] mtd: Fix partition alignment check on multi-erasesize devices

[Boris Brezillon]

Commit 1eeef2d7483a ("mtd: handle partitioning on devices with 0
erasesize") introduced a regression on heterogeneous erase region
devices. Alignment of the partition was tested against the master
eraseblock size which can be bigger than the slave one, thus leading
to some partitions being marked as read-only.

Update wr_alignment to match this slave erasesize after this erasesize
has been determined by picking the biggest erasesize of all the regions
embedded in the MTD partition.

Reported-by: Mathias Thore <Mathias.Thore@infinera.com>
Fixes: 1eeef2d7483a ("mtd: handle partitioning on devices with 0 erasesize")
Cc: <stable@vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
Changes in v2:
- Fix build error reported by Mathias
---
 drivers/mtd/mtdpart.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 5736b0c90b33..a308e707392d 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -581,6 +581,14 @@ static struct mtd_part *allocate_partition(struct mtd_info *parent,
 		slave->mtd.erasesize = parent->erasesize;
 	}
 
+	/*
+	 * Slave erasesize might differ from the master one if the master
+	 * exposes several regions with different erasesize. Adjust
+	 * wr_alignment accordingly.
+	 */
+	if (!(slave->mtd.flags & MTD_NO_ERASE))
+		wr_alignment = slave->mtd.erasesize;
+
 	tmp = slave->offset;
 	remainder = do_div(tmp, wr_alignment);
 	if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
-- 
2.11.0

RE: [PATCH v2] mtd: Fix partition alignment check on multi-erasesize devices

[Mathias Thore]

> -----Original Message-----
> From: Boris Brezillon [mailto:boris.brezillon@free-electrons.com]
> Sent: den 25 september 2017 10:20
> To: David Woodhouse; Brian Norris; Boris Brezillon; Marek Vasut; Richard
> Weinberger; Cyrille Pitchen; linux-mtd@lists.infradead.org
> Cc: Mathias Thore; Chris Packham; stable@vger.kernel.org
> Subject: [PATCH v2] mtd: Fix partition alignment check on multi-erasesize
> devices
> 
> Commit 1eeef2d7483a ("mtd: handle partitioning on devices with 0
> erasesize") introduced a regression on heterogeneous erase region devices.
> Alignment of the partition was tested against the master eraseblock size
> which can be bigger than the slave one, thus leading to some partitions being
> marked as read-only.
> 
> Update wr_alignment to match this slave erasesize after this erasesize has
> been determined by picking the biggest erasesize of all the regions
> embedded in the MTD partition.
> 
> Reported-by: Mathias Thore <Mathias.Thore@infinera.com>
> Fixes: 1eeef2d7483a ("mtd: handle partitioning on devices with 0 erasesize")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Tested-by: Mathias Thore <Mathias.Thore@infinera.com>
Reviewed-by: Mathias Thore <Mathias.Thore@infinera.com>

> ---
> Changes in v2:
> - Fix build error reported by Mathias
> ---
>  drivers/mtd/mtdpart.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index
> 5736b0c90b33..a308e707392d 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -581,6 +581,14 @@ static struct mtd_part *allocate_partition(struct
> mtd_info *parent,
>  		slave->mtd.erasesize = parent->erasesize;
>  	}
> 
> +	/*
> +	 * Slave erasesize might differ from the master one if the
> master
> +	 * exposes several regions with different erasesize. Adjust
> +	 * wr_alignment accordingly.
> +	 */
> +	if (!(slave->mtd.flags & MTD_NO_ERASE))
> +		wr_alignment = slave->mtd.erasesize;
> +
>  	tmp = slave->offset;
>  	remainder = do_div(tmp, wr_alignment);
>  	if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {
> --
> 2.11.0

Re: [PATCH v2] mtd: Fix partition alignment check on multi-erasesize devices

[Boris Brezillon]

On Mon, 25 Sep 2017 10:19:57 +0200
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:

> Commit 1eeef2d7483a ("mtd: handle partitioning on devices with 0
> erasesize") introduced a regression on heterogeneous erase region
> devices. Alignment of the partition was tested against the master
> eraseblock size which can be bigger than the slave one, thus leading
> to some partitions being marked as read-only.
> 
> Update wr_alignment to match this slave erasesize after this erasesize
> has been determined by picking the biggest erasesize of all the regions
> embedded in the MTD partition.
> 
> Reported-by: Mathias Thore <Mathias.Thore@infinera.com>
> Fixes: 1eeef2d7483a ("mtd: handle partitioning on devices with 0 erasesize")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Applied.

> ---
> Changes in v2:
> - Fix build error reported by Mathias
> ---
>  drivers/mtd/mtdpart.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index 5736b0c90b33..a308e707392d 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -581,6 +581,14 @@ static struct mtd_part *allocate_partition(struct mtd_info *parent,
>  		slave->mtd.erasesize = parent->erasesize;
>  	}
>  
> +	/*
> +	 * Slave erasesize might differ from the master one if the master
> +	 * exposes several regions with different erasesize. Adjust
> +	 * wr_alignment accordingly.
> +	 */
> +	if (!(slave->mtd.flags & MTD_NO_ERASE))
> +		wr_alignment = slave->mtd.erasesize;
> +
>  	tmp = slave->offset;
>  	remainder = do_div(tmp, wr_alignment);
>  	if ((slave->mtd.flags & MTD_WRITEABLE) && remainder) {