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 07/10] block: use sectors_to_npage() and PAGE_SECTORS to clean up code
Date: Fri, 15 May 2020 14:52:26 +0800 [thread overview]
Message-ID: <d3e9bebf-1fea-1497-6dd2-9354f9ca0d4b@huawei.com> (raw)
In-Reply-To: <20200515041916.GE16070@bombadil.infradead.org>
On 2020/5/15 12:19, Matthew Wilcox wrote:
> On Thu, May 07, 2020 at 03:50:57PM +0800, Zhen Lei wrote:
>> +++ b/block/blk-settings.c
>> @@ -150,7 +150,7 @@ void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_secto
>> unsigned int max_sectors;
>>
>> if ((max_hw_sectors << 9) < PAGE_SIZE) {
>> - max_hw_sectors = 1 << (PAGE_SHIFT - 9);
>> + max_hw_sectors = PAGE_SECTORS;
>
> Surely this should be:
>
> if (max_hw_sectors < PAGE_SECTORS) {
> max_hw_sectors = PAGE_SECTORS;
>
> ... no?
I've noticed this place before. "(max_hw_sectors << 9) < PAGE_SIZE" can also make sure
that max_hw_sectors is not too large, that means (max_hw_sectors << 9) may overflow.
>
>> - page = read_mapping_page(mapping,
>> - (pgoff_t)(n >> (PAGE_SHIFT - 9)), NULL);
>> + page = read_mapping_page(mapping, (pgoff_t)sectors_to_npage(n), NULL);
>
> ... again, get the type right, and you won't need the cast.
OK, I'll consider it.
>
>
> .
>
next prev parent reply other threads:[~2020-05-15 6:52 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)
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) [this message]
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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