Re: [PATCH] PM / Hibernate : Use get_gendisk to verify partition if resume_file is integer format

From: Rafael J. Wysocki
Date: Sat May 12 2012 - 17:34:47 EST


On Wednesday, May 09, 2012, Minho Ban wrote:
> Sometimes resume= parameter comes in integer style (e.g. major:minor) then
> name_to_dev_t can not detect partition properly. (especially async device like
> usb, mmc)
> This patch calls get_gendisk if resumewait is true and resume_file is in integer
> format.
>
> Signed-off-by: Minho Ban <mhban@xxxxxxxxxxx>
> ---
> Documentation/kernel-parameters.txt | 2 ++
> kernel/power/hibernate.c | 13 +++++++++++++
> 2 files changed, 15 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index c1601e5..5900b49 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -2372,6 +2372,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>
> resume= [SWSUSP]
> Specify the partition device for software suspend
> + Format:
> + {/dev/<dev> | PARTUUID=<uuid> | <int>:<int> | <hex>}
>
> resume_offset= [SWSUSP]
> Specify the offset from the beginning of the partition
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index e09dfbf..8b53db3 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -25,6 +25,8 @@
> #include <linux/freezer.h>
> #include <linux/gfp.h>
> #include <linux/syscore_ops.h>
> +#include <linux/ctype.h>
> +#include <linux/genhd.h>
> #include <scsi/scsi_scan.h>
>
> #include "power.h"
> @@ -722,6 +724,17 @@ static int software_resume(void)
>
> /* Check if the device is there */
> swsusp_resume_device = name_to_dev_t(resume_file);
> +
> + /*
> + * name_to_dev_t is ineffective to verify parition if resume_file is in
> + * integer format. (e.g. major:minor)
> + */
> + if (isdigit(resume_file[0]) && resume_wait) {
> + int partno;
> + while (!get_gendisk(swsusp_resume_device, &partno))
> + msleep(10);
> + }

Hmm. Wouldn't it be better to do:

if (isdigit(resume_file[0]) && resume_wait) {
int partno;
while (!get_gendisk(swsusp_resume_device, &partno))
msleep(10);
} else {
swsusp_resume_device = name_to_dev_t(resume_file);
}

?

Your new code will overwrite whatever swsusp_resume_device is set to by the
preceding statement anyway.

> +
> if (!swsusp_resume_device) {
> /*
> * Some device discovery might still be in progress; we need
>

Thanks,
Rafael
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