From: Tejun Heo <tj@kernel.org>
To: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: axboe@kernel.dk, bharrosh@panasas.com,
linux-kernel@vger.kernel.org, tj@kenel.org
Subject: Re: [PATCH 8/8] blk-map: reimplement blk_rq_map_user() using blk_rq_map_user_iov()
Date: Wed, 01 Apr 2009 22:18:23 +0900 [thread overview]
Message-ID: <49D3699F.4030105@kernel.org> (raw)
In-Reply-To: <49D36951.9000604@kernel.org>
Tejun Heo wrote:
>>> reason blk_rq_map_user() had multiple bio chaining was to work around
>>> BIO_MAX_SIZE. blk_rq_map_user_iov() doesn't support multiple bio
>>> chaining, so sans blk_rq_append_bio() or playing with rq/bio internals
>>> directly, there's no way to use or even know about multiple bios.
>> Yes, only non iovec interface of SG_IO supports large data
>> transfer. Users have been lived with that.
>
> This patch doesn't remove any feature. You don't lose anything. What
> used to be done with multiple bios is now done with single bio. The
> implementation is simpler and shorter. Using or not using multiple
> bios doesn't (and shouldn't) make any difference to blk_map_*() users.
Oh.. and blk_rq_map_user_iov() now gets to play with large requests
too. :-)
--
tejun
next prev parent reply other threads:[~2009-04-01 13:18 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-01 11:04 [GIT PATCHSET block#for-linus] block: blk-map related fixes Tejun Heo
2009-04-01 11:04 ` [PATCH 1/8] scatterlist: make sure sg_miter_next() doesn't return 0 sized mappings Tejun Heo
2009-04-01 11:04 ` [PATCH 2/8] block: fix SG_IO vector request data length handling Tejun Heo
2009-04-01 11:47 ` FUJITA Tomonori
2009-04-01 11:50 ` Jens Axboe
2009-04-01 12:18 ` FUJITA Tomonori
2009-04-01 12:24 ` Jens Axboe
2009-04-01 12:27 ` Tejun Heo
2009-04-01 12:29 ` Jens Axboe
2009-04-01 11:04 ` [PATCH 3/8] block: fix queue bounce limit setting Tejun Heo
2009-04-01 11:04 ` [PATCH 4/8] bio: actually inline inline bvecs into bio Tejun Heo
2009-04-01 12:47 ` Jens Axboe
2009-04-01 12:55 ` Tejun Heo
2009-04-01 12:59 ` Jens Axboe
2009-04-01 11:04 ` [PATCH 5/8] bio: fix bio_kmalloc() Tejun Heo
2009-04-01 11:04 ` [PATCH 6/8] bio: remove size/segments limit on bio_{copy|map}_{user|kern}*() Tejun Heo
2009-04-01 11:04 ` [PATCH 7/8] blk-map: let blk_rq_map_user_iov() support null mapping Tejun Heo
2009-04-01 11:54 ` FUJITA Tomonori
2009-04-01 12:03 ` Tejun Heo
2009-04-01 11:04 ` [PATCH 8/8] blk-map: reimplement blk_rq_map_user() using blk_rq_map_user_iov() Tejun Heo
2009-04-01 12:44 ` FUJITA Tomonori
2009-04-01 12:50 ` Tejun Heo
2009-04-01 12:59 ` FUJITA Tomonori
2009-04-01 13:03 ` Tejun Heo
2009-04-01 13:10 ` FUJITA Tomonori
2009-04-01 13:17 ` Tejun Heo
2009-04-01 13:18 ` Tejun Heo [this message]
2009-04-01 13:22 ` FUJITA Tomonori
2009-04-01 13:28 ` Tejun Heo
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