From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: sg driver and Fedora Core 2 Date: Sat, 29 May 2004 19:29:20 +0200 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20040529172916.GD18613@suse.de> References: <40B74725.90403@torque.net> <20040528172535.GD13961@devserv.devel.redhat.com> <1085846125.2101.29.camel@mulgrave> <20040529155744.GA32621@devserv.devel.redhat.com> <1085846840.2103.47.camel@mulgrave> <20040529162912.GA5922@devserv.devel.redhat.com> <1085849399.2004.101.camel@mulgrave> <40B8C81E.3050106@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from ns.virtualhost.dk ([195.184.98.160]:10222 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S264337AbUE2R3g (ORCPT ); Sat, 29 May 2004 13:29:36 -0400 Content-Disposition: inline In-Reply-To: <40B8C81E.3050106@pobox.com> List-Id: linux-scsi@vger.kernel.org To: Jeff Garzik Cc: SCSI Mailing List , James Bottomley , Alan Cox , Douglas Gilbert , Arjan van de Ven On Sat, May 29 2004, Jeff Garzik wrote: > Really what needs to happen is a generic userland tap attaches to a > chrdev, issues an ioctl(2) to attach to a request_queue, and then does > read(2)/write(2)/mmap(2) to communicate with the request_queue. > > :) > > Call it /dev/bsg, or somesuch. > > The SG_IO ioctl won't work for all cases, since some block devices may > rightly wish to limit (or block) multiple openers on the blkdev itself. > OTOH, the SG_IO ioctl does eliminate the userland app needing to > worry about _any_ target/addressing information, since that is implicit > in the dentry pointing to the blkdev's inode. Hear, hear! -- Jens Axboe