From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH 1/2] block: Modify blk_rq_map_user to support large requests Date: Wed, 13 Sep 2006 11:30:09 +0200 Message-ID: <20060913093009.GF23515@kernel.dk> References: <1157835221.4543.10.camel@max> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from brick.kernel.dk ([62.242.22.158]:8032 "EHLO kernel.dk") by vger.kernel.org with ESMTP id S1750715AbWIMJbz (ORCPT ); Wed, 13 Sep 2006 05:31:55 -0400 Content-Disposition: inline In-Reply-To: <1157835221.4543.10.camel@max> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Mike Christie Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org On Sat, Sep 09 2006, Mike Christie wrote: > Currently, there is some duplication between bsg, scsi_ioctl.c > and scsi_lib.c/sg/st in its mapping code. This patch modifies > the block layer blk_rq_map_user code to support large requests so > that the scsi and block drivers can use this common code. The > changes also make it so the callers do not have to account for > the bio to be unmapped and bounce buffers. > > The next patch then coverts bsg.c, scsi_ioctl.c and cdrom.c > to use the updated functions. For scsi_ioctl.c and cdrom.c > the only thing that changes is that they no longer have > to do the bounce buffer management and pass in the len for > the unmapping. The bsg change is a little larger since that > code was duplicating a lot of code that is now common > in the block layer. The bsg conversions als should fix > a memory leak caused when unmapping a hdr with iovec_count=0. > > Patch was made over Jens's block tree and the bsg branch Generally it looks good - two comments: - I see some advantages to having biohead_orig to avoid keeping track of it and passing it around, but there's also good reasons for _not_ adding more stuff to struct request. Any particular reason you chose to do that? - blk_get_bounced_bio() looks redundant. BIO_BOUNCED should only be set on a bounced bio, and ->bi_private should always hold that bounced bio. -- Jens Axboe