From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 4/4] scsi_debug: allow huge transfer length for read/write commands Date: Wed, 28 May 2014 03:39:55 -0700 Message-ID: <20140528103955.GD13542@infradead.org> References: <1401021816-10423-1-git-send-email-akinobu.mita@gmail.com> <1401021816-10423-5-git-send-email-akinobu.mita@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from bombadil.infradead.org ([198.137.202.9]:54862 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751778AbaE1Kjz (ORCPT ); Wed, 28 May 2014 06:39:55 -0400 Content-Disposition: inline In-Reply-To: <1401021816-10423-5-git-send-email-akinobu.mita@gmail.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Akinobu Mita Cc: linux-scsi@vger.kernel.org, Jens Axboe , "James E.J. Bottomley" , Douglas Gilbert On Sun, May 25, 2014 at 09:43:36PM +0900, Akinobu Mita wrote: > This change enables to test read/write commands with huge transfer > length such as 1GB. For example: > > # modprobe scsi_debug dev_size_mb=1024 clustering=1 opts=1 > # cat /sys/block/$DEV/queue/max_hw_sectors_kb > \ > /sys/block/$DEV/queue/max_sectors_kb > # fio --name=test --rw=write --bs=1g --size=1g --filename=/dev/$DEV \ > --mem=mmaphuge --direct=1 > > The data type of max_sectors in scsi_host_template has been extended > to unsigned int by the previous change. So we can increase it from > 0xffff to 0xffffffff to allow such huge transfer length. > > Also, this increases sg_tablesize and max_segment_size, otherwise the > maximum transfer length is limited to 64MB. > (sg_tablesize * max_segment_size = 256 * 256KB) > > Signed-off-by: Akinobu Mita Looks good, Reviewed-by: Christoph Hellwig