linux-kernel - Re: [RFC PATCHv5 3/6] zram: take write lock in wb limit store handlers

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Message-ID: <CADyq12zV=HkDOzvfngY_5yCCavdq4n-k6XeVFJBKkVSX_eP8yw@mail.gmail.com>
Date: Thu, 20 Nov 2025 11:03:04 -0500
From: Brian Geffon <bgeffon@...gle.com>
To: Sergey Senozhatsky <senozhatsky@...omium.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>, Minchan Kim <minchan@...nel.org>, 
	Yuwen Chen <ywen.chen@...mail.com>, Richard Chang <richardycc@...gle.com>, 
	Fengyu Lian <licayy@...look.com>, linux-kernel@...r.kernel.org, linux-mm@...ck.org, 
	linux-block@...r.kernel.org
Subject: Re: [RFC PATCHv5 3/6] zram: take write lock in wb limit store handlers

On Thu, Nov 20, 2025 at 10:22 AM Sergey Senozhatsky
<senozhatsky@...omium.org> wrote:
>
> Write device attrs handlers should take write zram init_lock.
> While at it, fixup coding styles.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>

Reviewed-by: Brian Geffon <bgeffon@...gle.com>

> ---
>  drivers/block/zram/zram_drv.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 7904159e9226..71f37b960812 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -519,7 +519,8 @@ struct zram_wb_req {
>  };
>
>  static ssize_t writeback_limit_enable_store(struct device *dev,
> -               struct device_attribute *attr, const char *buf, size_t len)
> +                                           struct device_attribute *attr,
> +                                           const char *buf, size_t len)
>  {
>         struct zram *zram = dev_to_zram(dev);
>         u64 val;
> @@ -528,18 +529,19 @@ static ssize_t writeback_limit_enable_store(struct device *dev,
>         if (kstrtoull(buf, 10, &val))
>                 return ret;
>
> -       down_read(&zram->init_lock);
> +       down_write(&zram->init_lock);
>         spin_lock(&zram->wb_limit_lock);
>         zram->wb_limit_enable = val;
>         spin_unlock(&zram->wb_limit_lock);
> -       up_read(&zram->init_lock);
> +       up_write(&zram->init_lock);
>         ret = len;
>
>         return ret;
>  }
>
>  static ssize_t writeback_limit_enable_show(struct device *dev,
> -               struct device_attribute *attr, char *buf)
> +                                          struct device_attribute *attr,
> +                                          char *buf)
>  {
>         bool val;
>         struct zram *zram = dev_to_zram(dev);
> @@ -554,7 +556,8 @@ static ssize_t writeback_limit_enable_show(struct device *dev,
>  }
>
>  static ssize_t writeback_limit_store(struct device *dev,
> -               struct device_attribute *attr, const char *buf, size_t len)
> +                                    struct device_attribute *attr,
> +                                    const char *buf, size_t len)
>  {
>         struct zram *zram = dev_to_zram(dev);
>         u64 val;
> @@ -563,11 +566,11 @@ static ssize_t writeback_limit_store(struct device *dev,
>         if (kstrtoull(buf, 10, &val))
>                 return ret;
>
> -       down_read(&zram->init_lock);
> +       down_write(&zram->init_lock);
>         spin_lock(&zram->wb_limit_lock);
>         zram->bd_wb_limit = val;
>         spin_unlock(&zram->wb_limit_lock);
> -       up_read(&zram->init_lock);
> +       up_write(&zram->init_lock);
>         ret = len;
>
>         return ret;
> --
> 2.52.0.rc1.455.g30608eb744-goog
>