From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>, Nitin Gupta <ngupta@vflare.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Jens Axboe <axboe@kernel.dk>, Coly Li <colyli@suse.de>,
Kent Overstreet <kent.overstreet@gmail.com>,
Alasdair Kergon <agk@redhat.com>,
Mike Snitzer <snitzer@redhat.com>,
linux-block <linux-block@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm <linux-mm@kvack.org>, dm-devel <dm-devel@redhat.com>,
Song Liu <song@kernel.org>,
linux-raid <linux-raid@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 06/10] mm/swap: use npage_to_sectors() and PAGE_SECTORS to clean up code
Date: Fri, 15 May 2020 14:28:53 +0800 [thread overview]
Message-ID: <766da107-bc67-ff99-a8c8-87f8f98c7cf6@huawei.com> (raw)
In-Reply-To: <20200515040647.GC16070@bombadil.infradead.org>
On 2020/5/15 12:06, Matthew Wilcox wrote:
> On Thu, May 07, 2020 at 03:50:56PM +0800, Zhen Lei wrote:
>> @@ -266,7 +266,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
>>
>> static sector_t swap_page_sector(struct page *page)
>> {
>> - return (sector_t)__page_file_index(page) << (PAGE_SHIFT - 9);
>> + return npage_to_sectors((sector_t)__page_file_index(page));
>
> If you make npage_to_sectors() a proper function instead of a macro,
> you can do the casting inside the function instead of in the callers
> (which is prone to bugs).
Oh, yes. __page_file_index(page) maybe called many times in marco, althouth currently
it is not. So that, not all are suitable for page_to_sector(). And for this example,
still need to use "<< PAGE_SECTORS_SHIFT".
>
> Also, this is a great example of why page_to_sector() was a better name
> than npage_to_sectors(). This function doesn't return a count of sectors,
> it returns a sector number within the swap device.
OK, so I will change to page_to_sector()/sector_to_page().
>
>
> .
>
next prev parent reply other threads:[~2020-05-15 6:28 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 7:50 [PATCH v2 00/10] clean up SECTOR related macros and sectors/pages conversions Zhen Lei
2020-05-07 7:50 ` [PATCH v2 01/10] block: move PAGE_SECTORS definition into <linux/blkdev.h> Zhen Lei
2020-05-07 7:50 ` [PATCH v2 02/10] zram: abolish macro SECTORS_PER_PAGE Zhen Lei
2020-05-07 7:50 ` [PATCH v2 03/10] block: add sectors_to_npage()/npage_to_sectors() helpers Zhen Lei
2020-05-07 7:50 ` [PATCH v2 04/10] zram: abolish macro SECTORS_PER_PAGE_SHIFT Zhen Lei
2020-05-07 7:50 ` [PATCH v2 05/10] block: abolish macro PAGE_SECTORS_SHIFT Zhen Lei
2020-05-07 7:50 ` [PATCH v2 06/10] mm/swap: use npage_to_sectors() and PAGE_SECTORS to clean up code Zhen Lei
2020-05-15 4:06 ` Matthew Wilcox
2020-05-15 6:28 ` Leizhen (ThunderTown) [this message]
2020-05-15 4:14 ` Matthew Wilcox
2020-05-15 6:42 ` Leizhen (ThunderTown)
2020-05-07 7:50 ` [PATCH v2 07/10] block: use sectors_to_npage() " Zhen Lei
2020-05-15 4:19 ` Matthew Wilcox
2020-05-15 6:52 ` Leizhen (ThunderTown)
2020-05-07 7:50 ` [PATCH v2 08/10] md: use sectors_to_npage() and npage_to_sectors() " Zhen Lei
2020-05-07 7:50 ` [PATCH v2 09/10] md: use existing definition RESYNC_SECTORS Zhen Lei
2020-05-07 7:51 ` [PATCH v2 10/10] md: use PAGE_SECTORS to clean up code Zhen Lei
2020-05-15 2:05 ` [PATCH v2 00/10] clean up SECTOR related macros and sectors/pages conversions Leizhen (ThunderTown)
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