lkml.org 
[lkml]   [2013]   [Oct]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v8 2/3] Staging: zram: Fix decrement of variable by calling bdput()
From
Hello, Rashika

On Wed, Oct 30, 2013 at 9:10 PM, Rashika Kheria
<rashika.kheria@gmail.com> wrote:
> As suggested by Jerome Marchand "The code in reset_store get the block device
> (bdget_disk()) but it does not put it (bdput()) when it's done using it.
> The usage count is therefore incremented but never decremented."
>
> This patch also puts bdput() for all error cases.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
> ---
>
> This revision fixes the following issues of the previous revision-
> Proper error handling
>
> drivers/staging/zram/zram_drv.c | 25 ++++++++++++++++++-------
> 1 file changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
> index 012ba15..0bc2835 100644
> --- a/drivers/staging/zram/zram_drv.c
> +++ b/drivers/staging/zram/zram_drv.c
> @@ -648,25 +648,36 @@ static ssize_t reset_store(struct device *dev,
> zram = dev_to_zram(dev);
> bdev = bdget_disk(zram->disk, 0);
>
> - if (!bdev)
> - return -ENOMEM;
> + if (!bdev) {
> + ret = -ENOMEM;
> + goto out;
> + }

If bdev is NULL, just return -ENOMEM; DO NOT goto out;
or you will get a NULL point reference in bdput(bdev);

> /* Do not reset an active device! */
> - if (bdev->bd_holders)
> - return -EBUSY;
> + if (bdev->bd_holders) {
> + ret = -EBUSY;
> + goto out;
> + }
>
> ret = kstrtou16(buf, 10, &do_reset);
> if (ret)
> - return ret;
> + goto out;
>
> - if (!do_reset)
> - return -EINVAL;
> + if (!do_reset) {
> + ret = -EINVAL;
> + goto out;
> + }
>
> /* Make sure all pending I/O is finished */
> fsync_bdev(bdev);
> + bdput(bdev);
>
> zram_reset_device(zram, true);
> return len;
> +
> +out:
> + bdput(bdev);
> + return ret;
> }
>
> static void __zram_make_request(struct zram *zram, struct bio *bio, int rw)
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/


\
 
 \ /
  Last update: 2013-10-31 11:21    [W:0.143 / U:1.564 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site