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Date:   Tue, 10 Apr 2018 15:22:11 +0900
From:   Minchan Kim <minchan@kernel.org>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v3 4/4] zram: introduce zram memory tracking
Message-ID: <20180410062211.GB38000@rodete-desktop-imager.corp.google.com>
References: <20180409055435.135695-1-minchan@kernel.org>
 <20180409055435.135695-5-minchan@kernel.org>
 <20180410000305.GA6942@jagdpanzerIV>
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On Tue, Apr 10, 2018 at 09:03:05AM +0900, Sergey Senozhatsky wrote:
> Hi Minchan,
> 
> On (04/09/18 14:54), Minchan Kim wrote:
> > +static long long ns2usecs(u64 nsec)
> > +{
> > +	nsec += 500;
> > +	do_div(nsec, 1000);
> > +	return nsec;
> > +}
> 
> Sorry, I don't quite understand "nsec += 500".

Round-off

> 
> > +static ssize_t read_block_state(struct file *file, char __user *buf,
> > +				size_t count, loff_t *ppos)
> > +{
> [..]
> > +
> > +	up_read(&zram->init_lock);
> > +	copy_to_user(buf, kbuf, written);
> 
> drivers/block/zram/zram_drv.c: In function ‘read_block_state’:
> drivers/block/zram/zram_drv.c:701:2: warning: ignoring return value of ‘copy_to_user’, declared with attribute warn_unused_result [-Wunused-result]
>   copy_to_user(buf, kbuf, written);
>   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Good catch.

> 
> [..]
> > @@ -61,7 +61,9 @@ struct zram_table_entry {
> >  		unsigned long element;
> >  	};
> >  	unsigned long value;
> > +#ifdef	CONFIG_ZRAM_MEMORY_TRACKING
> 
> A silly nitpick, but since you are going to resend this one, could you
> remove TAB between ifdef and CONFIG_ZRAM_MEMORY_TRACKING?

Sure.