linux-kernel - Re: [PATCH 2/5] ufs: Rename of regulator_set_optimum

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Message-ID: <CAC5umyisp-aWU1mGajCCwS5yxaJvqh1UHUACEXb2ixHk5_+fJA@mail.gmail.com>
Date:	Tue, 14 Apr 2015 21:11:58 +0900
From:	Akinobu Mita <akinobu.mita@...il.com>
To:	Bjorn Andersson <bjorn.andersson@...ymobile.com>
Cc:	Vinayak Holikatti <vinholikatti@...il.com>,
	"James E.J. Bottomley" <JBottomley@...allels.com>,
	Mark Brown <broonie@...nel.org>,
	"linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH 2/5] ufs: Rename of regulator_set_optimum_mode

2015-02-12 12:35 GMT+09:00 Bjorn Andersson <bjorn.andersson@...ymobile.com>:
> The function regulator_set_optimum_mode() is changing name to
> regulator_set_load(), so update the code accordingly. Also cleaned up
> ufshcd_config_vreg_load() while touching the code.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...ymobile.com>
> ---
>  drivers/scsi/ufs/ufshcd.c | 27 +++++++--------------------
>  1 file changed, 7 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 2e4614b..4b73b94 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -4225,22 +4225,15 @@ static struct scsi_host_template ufshcd_driver_template = {
>  static int ufshcd_config_vreg_load(struct device *dev, struct ufs_vreg *vreg,
>                                    int ua)
>  {
> -       int ret = 0;
> -       struct regulator *reg = vreg->reg;
> -       const char *name = vreg->name;
> +       int ret;
>
> -       BUG_ON(!vreg);
> +       if (!vreg)
> +               return 0;
>
> -       ret = regulator_set_optimum_mode(reg, ua);
> -       if (ret >= 0) {
> -               /*
> -                * regulator_set_optimum_mode() returns new regulator
> -                * mode upon success.
> -                */
> -               ret = 0;
> -       } else {
> -               dev_err(dev, "%s: %s set optimum mode(ua=%d) failed, err=%d\n",
> -                               __func__, name, ua, ret);
> +       ret = regulator_set_load(vreg->reg, ua);
> +       if (ret < 0) {
> +               dev_err(dev, "%s: %s set load (ua=%d) failed, err=%d\n",
> +                               __func__, vreg->name, ua, ret);
>         }
>
>         return ret;
> @@ -4249,18 +4242,12 @@ static int ufshcd_config_vreg_load(struct device *dev, struct ufs_vreg *vreg,
>  static inline int ufshcd_config_vreg_lpm(struct ufs_hba *hba,
>                                          struct ufs_vreg *vreg)
>  {
> -       if (!vreg)
> -               return 0;
> -
>         return ufshcd_config_vreg_load(hba->dev, vreg, UFS_VREG_LPM_LOAD_UA);
>  }
>
>  static inline int ufshcd_config_vreg_hpm(struct ufs_hba *hba,
>                                          struct ufs_vreg *vreg)
>  {
> -       if (!vreg)
> -               return 0;
> -
>         return ufshcd_config_vreg_load(hba->dev, vreg, vreg->max_uA);
>  }

I tried this patch and it caused kernel null pointer dereference with
'verg->max_uA' when vreg == NULL.  So you can't simply move !vreg check here
into ufshcd_config_vreg_load().
--
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