From: Jens Axboe <axboe@kernel.dk>
To: Geert Uytterhoeven <geert@linux-m68k.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] block: Do not call sector_div() with a 64-bit divisor
Date: Mon, 04 Nov 2013 15:29:43 -0700 [thread overview]
Message-ID: <52781FD7.9050507@kernel.dk> (raw)
In-Reply-To: <1383570006-4605-1-git-send-email-geert@linux-m68k.org>
On 11/04/2013 06:00 AM, Geert Uytterhoeven wrote:
> do_div() (called by sector_div() if CONFIG_LBDAF=y) is meant for divisions
> of 64-bit number by 32-bit numbers. Passing 64-bit divisor types caused
> issues in the past on 32-bit platforms, cfr. commit
> ea077b1b96e073eac5c3c5590529e964767fc5f7 ("m68k: Truncate base in
> do_div()").
>
> As queue_limits.max_discard_sectors and .discard_granularity are unsigned
> int, max_discard_sectors and granularity should be unsigned int.
> As bdev_discard_alignment() returns int, alignment should be int.
> Now 2 calls to sector_div() can be replaced by 32-bit arithmetic:
> - The 64-bit modulo operation can become a 32-bit modulo operation,
> - The 64-bit division and multiplication can be replaced by a 32-bit
> modulo operation and a subtraction.
Thanks Geert, applied.
--
Jens Axboe
prev parent reply other threads:[~2013-11-04 22:30 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-04 13:00 [PATCH] block: Do not call sector_div() with a 64-bit divisor Geert Uytterhoeven
2013-11-04 22:29 ` Jens Axboe [this message]
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