From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261641AbVDTPB5 (ORCPT ); Wed, 20 Apr 2005 11:01:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261671AbVDTPB5 (ORCPT ); Wed, 20 Apr 2005 11:01:57 -0400 Received: from rproxy.gmail.com ([64.233.170.206]:6249 "EHLO rproxy.gmail.com") by vger.kernel.org with ESMTP id S261637AbVDTPBy convert rfc822-to-8bit (ORCPT ); Wed, 20 Apr 2005 11:01:54 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=nqfljjkIoX589PBRD+D0f4w74EU1tSYs+QtUN1s9Ujc84bA+TUxCQi0Xgavk9pNJhAqkTDg4/Quok8TF0Nyo8d397aKy7f4gYFaIYxW1V1dt2AmtAlGBL8RWY68S2eiUUEzTILMhwETZUZF4N/IHCRlyS8nBO1W5cEah2HnP+V8= Message-ID: <363f92a8050420080112dec5db@mail.gmail.com> Date: Wed, 20 Apr 2005 08:01:53 -0700 From: Dheeraj Pandey Reply-To: Dheeraj Pandey To: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: writev to scsi disks Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I was wondering if I did a simple writev to a SCSI disk, does it take the sg path to the device? I am guessing sg (REQ_SPECIAL) is only true for character devices (and ioctl's) and not block devices. These are my questions: - Is sg a common feature among SCSI disks these days? How do I know what disks support this feature (any capabilities published by the driver)? - How does one make writev work for SCSI disk (as a block device) in direct_io? - If I use SCSI disks as character device, can I simply use writev on the character device file, and will sg codepath be taken?