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From: Baoquan He To: Chris Li 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: References: <20260417033951.1111038-1-baoquan.he@linux.dev> <20260417033951.1111038-3-baoquan.he@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 2742320015 X-Stat-Signature: kw3zcm1wpui6i9sxs4a1hjbwz8sye83p X-Rspam-User: X-HE-Tag: 1776822497-183314 X-HE-Meta: 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 a5nxASZQ cAENADxEg0R78koBJ2NHLqoQwpHqVcRXrTKbs5W+WHhlBbYgmdgpO47ey303i2cMI7yL8Kn8Oh/bxogqJUPDUw76rjtrT0DC6W4GGoCBXjinwwCoEBSp959SGzVegJ9J5Oh/fSyoQFtWtnvaZ276MNrvFFFbZg+SDl7xZ6/kb/WOcoQSLhsr/VtHQk/GTTwFeI6MZdC0zYFameUY8HEMwm7QNqMir9gYy9lJmlCT17atQJyhnOFZl+Mvv/89T4/O0rZii8dXlCjw6y+0el7l66p0PYYx5eMlyPeVPMEYG7x8NwFmsE0b3q0p+vRNwv+qSWzE9 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 04/17/26 at 07:30pm, Chris Li wrote: > On Thu, Apr 16, 2026 at 8:40 PM Baoquan He 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