From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [Bug 12207] block reads/writes > 122880 bytes to USB tape drive gives EBUSY Date: Tue, 23 Dec 2008 08:55:24 -0600 Message-ID: <1230044124.3461.1.camel@localhost.localdomain> References: <20081223135938.30266108042@picon.linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from accolon.hansenpartnership.com ([76.243.235.52]:33451 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751183AbYLWOz2 (ORCPT ); Tue, 23 Dec 2008 09:55:28 -0500 In-Reply-To: <20081223135938.30266108042@picon.linux-foundation.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: bugme-daemon@bugzilla.kernel.org Cc: linux-scsi@vger.kernel.org > ------- Comment #6 from stern@rowland.harvard.edu 2008-12-23 05:59 ------- > You can change the max_sectors setting through sysfs. However the last time I > looked, the block layer limited max_sectors to 512 KB or something on that > order, so you can't get too much improvement. > > Why is a limit of 120 KB unreasonably small? All it means is that you have to > use more system calls to transfer the same amount of data. Is anything wrong > with that? Tapes need large block sizes. We can accommodate both: Just check for TYPE_TAPE in the slave_configure() and bump the limit back up. Any USB tape that doesn't do large block transfers will be truly broken. James