From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753244Ab0IXUsT (ORCPT ); Fri, 24 Sep 2010 16:48:19 -0400 Received: from smtp101.sbc.mail.gq1.yahoo.com ([67.195.15.60]:42105 "HELO smtp101.sbc.mail.gq1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750793Ab0IXUsR (ORCPT ); Fri, 24 Sep 2010 16:48:17 -0400 X-Yahoo-SMTP: fzDSGlOswBCWnIOrNw7KwwK1j9PqyNbe5PtLKiS4dDU.UNl_t6bdEZu9tTLW X-YMail-OSG: t2Wkgk0VM1lcX5zt4rpjlmZphitjTu6tP5XolDgroU82irf Df_P27JFXn2uTwqfgGIoUiJDAE8P.D8QtRYLuCpvNi33ta32ZVcjmDSvNQTi .qlYe55YZKP.qA6G4tD0W6bFyQjno9YWcwzKM_rN3REQAMpigOxUQGSeZPAU n7Of92K.sN7biPOdpB7sk9wbAYLACAOOexG2kE0MU4aXyfKIuL_XgltkvC7X jlV.hSuLrt60s6SCyiILn3enOYfOxpQlmFrIlj16CRHdgIm1bolooOUKzg1s m87RLgiKKHboc9Jnlu4OoKR4- X-Yahoo-Newman-Property: ymail-3 Subject: Re: [RFC v3 01/15] scsi: Drop struct Scsi_Host->host_lock usage in scsi_dispatch_cmd() From: "Nicholas A. Bellinger" To: Brian King Cc: linux-scsi , linux-kernel , Vasu Dev , Tim Chen , Andi Kleen , Matthew Wilcox , James Bottomley , Mike Christie , James Smart , Andrew Vasquez , FUJITA Tomonori , Hannes Reinecke , Joe Eykholt , Christoph Hellwig , MPTFusionLinux , "eata.c maintainer" In-Reply-To: <4C9CAA80.1030702@linux.vnet.ibm.com> References: <1285285052-16351-1-git-send-email-nab@linux-iscsi.org> <4C9CAA80.1030702@linux.vnet.ibm.com> Content-Type: text/plain Date: Fri, 24 Sep 2010 13:44:00 -0700 Message-Id: <1285361040.1849.235.camel@haakon2.linux-iscsi.org> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2010-09-24 at 08:41 -0500, Brian King wrote: > On 09/23/2010 06:37 PM, Nicholas A. Bellinger wrote: > > @@ -651,7 +655,6 @@ static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd > > int scsi_dispatch_cmd(struct scsi_cmnd *cmd) > > { > > struct Scsi_Host *host = cmd->device->host; > > - unsigned long flags = 0; > > unsigned long timeout; > > int rtn = 0; > > > > @@ -736,15 +739,11 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd) > > scsi_done(cmd); > > goto out; > > } > > - > > - spin_lock_irqsave(host->host_lock, flags); > > /* > > - * AK: unlikely race here: for some reason the timer could > > - * expire before the serial number is set up below. > > - * > > - * TODO: kill serial or move to blk layer > > + * Note that scsi_cmd_get_serial() used to be called here, but > > + * now we expect the legacy SCSI LLDs that actually need this > > + * to call it directly within their SHT->queuecommand() caller. > > */ > > - scsi_cmd_get_serial(host, cmd); > > > > if (unlikely(host->shost_state == SHOST_DEL)) { > > cmd->result = (DID_NO_CONNECT << 16); > > @@ -753,7 +752,7 @@ int scsi_dispatch_cmd(struct scsi_cmnd *cmd) > > trace_scsi_dispatch_cmd_start(cmd); > > rtn = host->hostt->queuecommand(cmd, scsi_done); > > } > > - spin_unlock_irqrestore(host->host_lock, flags); > > + > > if (rtn) { > > trace_scsi_dispatch_cmd_error(cmd, rtn); > > if (rtn != SCSI_MLQUEUE_DEVICE_BUSY && > > Are you planning a future revision that moves the acquiring of the host lock > into the LLDD's queuecommand for all the other drivers you don't currently > touch in this patch set? > Hi Brian, I was under the impression that this would be unnecessary for the vast majority of existing LLD drivers, but if you are aware of specific LLDs that would still need the struct Scsi_Host->host_lock held in their SHT->queuecommand() for whaterver reason please let me know and I would be happy to include this into an RFCv4. Thanks for your comments! --nab