From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Date: Tue, 2 Sep 2008 07:20:19 +0000 (+0900)
Subject: block: make blk_rq_map_user take a NULL user-space buffer
X-Git-Tag: v2.6.28-rc1~733^2~57
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=818827669d85b84241696ffef2de485db46b0b5e;p=pandora-kernel.git

block: make blk_rq_map_user take a NULL user-space buffer

This patch changes blk_rq_map_user to accept a NULL user-space buffer
with a READ command if rq_map_data is not NULL. Thus a caller can pass
page frames to lk_rq_map_user to just set up a request and bios with
page frames propely. bio_uncopy_user (called via blk_rq_unmap_user)
doesn't copy data to user space with such request.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

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