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From: Baoquan He <baoquan.he@linux.dev>
To: Chris Li <chrisl@kernel.org>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org, usama.arif@linux.dev,
	baohua@kernel.org, kasong@tencent.com, nphamcs@gmail.com,
	shikemeng@huaweicloud.com, youngjun.park@lge.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/3] mm/swap: use swap_ops to register swap device's
 methods
Message-ID: <aego1T9d6PVudYqj@MiWiFi-R3L-srv>
References: <20260417033951.1111038-1-baoquan.he@linux.dev>
 <20260417033951.1111038-3-baoquan.he@linux.dev>
 <CACePvbWZO-=Nwho9Hfk-2HpuggZyb+Yt306MdA4X_icAt6+Z9w@mail.gmail.com>
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On 04/17/26 at 07:30pm, Chris Li wrote:
> On Thu, Apr 16, 2026 at 8:40 PM Baoquan He <baoquan.he@linux.dev> wrote:
...snip...
> > +int init_swap_ops(struct swap_info_struct *sis)
> > +{
> > +       /*
> > +        * ->flags can be updated non-atomically, but that will
> > +        * never affect SWP_FS_OPS, so the data_race is safe.
> > +        */
> > +       if (data_race(sis->flags & SWP_FS_OPS))
> > +               sis->ops = &bdev_fs_swap_ops;
> > +       /*
> > +        * ->flags can be updated non-atomically, but that will
> > +        * never affect SWP_SYNCHRONOUS_IO, so the data_race is safe.
> > +        */
> > +       else if (data_race(sis->flags & SWP_SYNCHRONOUS_IO))
> > +               sis->ops = &bdev_sync_swap_ops;
> > +       else
> > +               sis->ops = &bdev_async_swap_ops;
> > +
> > +       if (!sis->ops || !sis->ops->read_folio || !sis->ops->write_folio)
> > +               return -1;
> Nitpick:
> 
> For int type error return, you should use  -EINVAL or some thing with
> error code. If you don't care about error code, change the return type
> to bool instead.

Thanks for careful reviewing, returning -EINVAL looks better, I will
change like that and repost.

Thanks
Baoquan