From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
To: LKML <linux-kernel@vger.kernel.org>, Tejun Heo <tj@kernel.org>,
Andrew Morton <akpm@osdl.org>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
Jens Axboe <axboe@kernel.dk>, Kiyoshi Ueda <k-ueda@ct.jp.nec.com>,
Lin Ming <ming.m.lin@intel.com>, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] block:Remove extra condition in end of disk check
Date: Mon, 24 Jun 2013 19:20:12 +0530 [thread overview]
Message-ID: <51C84E94.8020100@linux.vnet.ibm.com> (raw)
In-Reply-To: <20130623171711.7127.16248.sendpatchset@codeblue.in.ibm.com>
CCing more relevant people (with the help of get_maintainer --git-blame)
On 06/23/2013 10:47 PM, Raghavendra K T wrote:
> From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
>
> Since #sector is always positive the reduced condition check
> encompasses maxsector < nr_sectors check.
>
> Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
> ---
> An userspace program looping with:
> maxsector - 0-9999
> nr_sector - 0-999
> sector - 0-999 gave 6.4% improvement with new condition though I agree that
> it is not the best way to test it perhaps :)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 33c33bc..4a78583 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1656,7 +1656,7 @@ static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
> if (maxsector) {
> sector_t sector = bio->bi_sector;
>
> - if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
> + if (maxsector - nr_sectors < sector) {
> /*
> * This may well happen - the kernel calls bread()
> * without checking the size of the device, e.g., when
>
>
next prev parent reply other threads:[~2013-06-24 13:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-23 17:17 [PATCH] block:Remove extra condition in end of disk check Raghavendra K T
2013-06-24 13:50 ` Raghavendra K T [this message]
2013-06-24 22:51 ` Tejun Heo
2013-06-25 5:10 ` Raghavendra K T
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