From: Tejun Heo <htejun@gmail.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: linux-scsi <linux-scsi@vger.kernel.org>,
linux-ide <linux-ide@vger.kernel.org>,
Jens Axboe <Jens.Axboe@oracle.com>,
FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
Jeff Garzik <jeff@garzik.org>
Subject: Re: [PATCH] libata: eliminate the home grown dma padding in favour of that provided by the block layer
Date: Wed, 09 Jan 2008 14:13:50 +0900 [thread overview]
Message-ID: <4784580E.3060000@gmail.com> (raw)
In-Reply-To: <1199852673.3534.76.camel@localhost.localdomain>
James Bottomley wrote:
>> Also, DMA alignment at
>> block layer isn't enough for ATA. ATA needs drain buffers for ATAPI
>> commands with variable length response. :-(
>
> OK, where is this in the libata code? The dma_pad size is only 4 bytes,
> so this drain, I assume is only a word long? Given the word alignment
> requirements of ATA doesn't this still mean it's only draining up to the
> word boundary anyway (so the code is still correct)?
Patch is acked but not merged yet.
http://git.kernel.org/?p=linux/kernel/git/tj/libata-dev.git;a=commit;h=6cd22a0febc74bebe52d58eb22271b8770892a2d
The full function can be read from the following. It's
ata_sg_setup_extra().
http://git.kernel.org/?p=linux/kernel/git/tj/libata-dev.git;a=blob;f=drivers/ata/libata-core.c;h=d763c072e6cefc724ea24cb68a7adf47b340f054;hb=6cd22a0febc74bebe52d58eb22271b8770892a2d
--
tejun
next prev parent reply other threads:[~2008-01-09 5:13 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-31 21:56 [PATCH] libata: eliminate the home grown dma padding in favour of that provided by the block layer James Bottomley
2007-12-31 22:56 ` Jeff Garzik
2008-01-03 7:58 ` FUJITA Tomonori
2008-01-03 15:12 ` James Bottomley
2008-01-09 2:10 ` Tejun Heo
2008-01-09 4:24 ` James Bottomley
2008-01-09 5:13 ` Tejun Heo [this message]
2008-01-09 15:13 ` James Bottomley
2008-01-18 23:14 ` [PATCH RESEND] " James Bottomley
2008-02-01 19:40 ` [PATCH RESEND number 2] " James Bottomley
2008-02-01 20:02 ` Jeff Garzik
2008-02-01 21:09 ` James Bottomley
2008-02-03 3:04 ` Tejun Heo
2008-02-03 4:32 ` James Bottomley
2008-02-03 7:37 ` Tejun Heo
2008-02-03 14:38 ` James Bottomley
2008-02-03 15:14 ` Tejun Heo
2008-02-03 16:12 ` James Bottomley
2008-02-03 16:38 ` Jeff Garzik
2008-02-03 17:12 ` James Bottomley
2008-02-04 1:21 ` Tejun Heo
2008-02-04 1:28 ` Tejun Heo
2008-02-04 9:25 ` Tejun Heo
2008-02-04 14:43 ` Tejun Heo
2008-02-04 16:23 ` James Bottomley
2008-02-05 0:06 ` Tejun Heo
2008-02-05 0:32 ` James Bottomley
2008-02-05 0:43 ` Tejun Heo
2008-02-05 0:53 ` James Bottomley
2008-02-05 1:07 ` Tejun Heo
2008-02-05 5:03 ` James Bottomley
2008-02-05 5:22 ` Tejun Heo
2008-02-04 15:43 ` James Bottomley
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