Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752753Ab0LTBNo (ORCPT ); Sun, 19 Dec 2010 20:13:44 -0500 Received: from mail.linux-iscsi.org ([67.23.28.174]:59181 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752370Ab0LTBNn (ORCPT ); Sun, 19 Dec 2010 20:13:43 -0500 Subject: Re: [PATCH 07/12] qla2xxx: Convert to host_lock less w/ interrupts disabled externally From: "Nicholas A. Bellinger" To: Matthew Wilcox Cc: linux-scsi , linux-kernel , James Bottomley , Jeff Garzik , Christoph Hellwig , FUJITA Tomonori , Hannes Reinecke , Mike Christie , Mike Anderson , Tejun Heo , Vasu Dev , Tim Chen , Andi Kleen , Ravi Anand , Andrew Vasquez , Joe Eykholt , James Smart , Douglas Gilbert , adam radford , Kashyap Desai , MPTFusionLinux In-Reply-To: <20101219231114.GI1263@parisc-linux.org> References: <1292793727-31957-1-git-send-email-nab@linux-iscsi.org> <1292793727-31957-8-git-send-email-nab@linux-iscsi.org> <20101219231114.GI1263@parisc-linux.org> Content-Type: text/plain Date: Sun, 19 Dec 2010 17:07:43 -0800 Message-Id: <1292807263.20840.20.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 Content-Length: 4485 Lines: 130 On Sun, 2010-12-19 at 16:11 -0700, Matthew Wilcox wrote: > On Sun, Dec 19, 2010 at 01:22:02PM -0800, Nicholas A. Bellinger wrote: > > This patch converts qla2xxx to run in host_lock less mode with the new > > IRQ_DISABLE_SCSI_QCMD() that disables interrupts while calling ->queuecommand() > > dispatch. It also drops the legacy host_lock unlock optimization. > > I'm not sure this is the right direction to go. Now that Jeff's done > the pushdown and put in the compatibility macros, I don't think it makes > sense to do another partial transition on each driver. Much better to > take our time, analyse each driver thoroughly, and kill the DEF_SCSI_QCMD > in each driver without introducing IRQ_DISABLE_SCSI_QCMD. Yes, the LLDs using IRQ_DISABLE_SCSI_QCMD in this series are the ones that we collectively know can be looked at for further optimization to use spin_lock_irq() around a LLD dependent lock to realize the extra benefit of not using local_irq_save(). The conversion of DEF_SCSI_QCMD -> IRQ_DISABLE_SCSI_QCMD is to signal this explictly to the other LLD folks that for the move to fully lock-less operation, that they want to be looking at what libiscsi, megaraid_sas, scsi_debug, tcm_loop and your qla2xxx patch is doing.. ;) > > In particular for this driver, it explicitly re-enables interrupts, > so it's pretty easy to do a full conversion. Compile-tested only. > Great, I will give this a shot with ISP25xx series HW and get this added as a incremental patch for -v3 branch, and ammended into the qla2xxx LLD patch for v4. Thanks Matthew! --nab > Convert qla2xxx driver to run without the shost lock > > Signed-off-by: Matthew Wilcox > > diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c > index 2c0876c..b44d986 100644 > --- a/drivers/scsi/qla2xxx/qla_os.c > +++ b/drivers/scsi/qla2xxx/qla_os.c > @@ -513,7 +513,7 @@ qla24xx_fw_version_str(struct scsi_qla_host *vha, char *str) > > static inline srb_t * > qla2x00_get_new_sp(scsi_qla_host_t *vha, fc_port_t *fcport, > - struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *)) > + struct scsi_cmnd *cmd) > { > srb_t *sp; > struct qla_hw_data *ha = vha->hw; > @@ -527,16 +527,15 @@ qla2x00_get_new_sp(scsi_qla_host_t *vha, fc_port_t *fcport, > sp->cmd = cmd; > sp->flags = 0; > CMD_SP(cmd) = (void *)sp; > - cmd->scsi_done = done; > sp->ctx = NULL; > > return sp; > } > > static int > -qla2xxx_queuecommand_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *)) > +qla2xxx_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmd) > { > - scsi_qla_host_t *vha = shost_priv(cmd->device->host); > + scsi_qla_host_t *vha = shost_priv(shost); > fc_port_t *fcport = (struct fc_port *) cmd->device->hostdata; > struct fc_rport *rport = starget_to_rport(scsi_target(cmd->device)); > struct qla_hw_data *ha = vha->hw; > @@ -544,7 +543,6 @@ qla2xxx_queuecommand_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *) > srb_t *sp; > int rval; > > - spin_unlock_irq(vha->host->host_lock); > if (ha->flags.eeh_busy) { > if (ha->flags.pci_channel_io_perm_failure) > cmd->result = DID_NO_CONNECT << 16; > @@ -577,39 +575,32 @@ qla2xxx_queuecommand_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *) > goto qc24_target_busy; > } > > - sp = qla2x00_get_new_sp(base_vha, fcport, cmd, done); > + sp = qla2x00_get_new_sp(base_vha, fcport, cmd); > if (!sp) > - goto qc24_host_busy_lock; > + goto qc24_host_busy; > > rval = ha->isp_ops->start_scsi(sp); > if (rval != QLA_SUCCESS) > goto qc24_host_busy_free_sp; > > - spin_lock_irq(vha->host->host_lock); > - > return 0; > > qc24_host_busy_free_sp: > qla2x00_sp_free_dma(sp); > mempool_free(sp, ha->srb_mempool); > > -qc24_host_busy_lock: > - spin_lock_irq(vha->host->host_lock); > +qc24_host_busy: > return SCSI_MLQUEUE_HOST_BUSY; > > qc24_target_busy: > - spin_lock_irq(vha->host->host_lock); > return SCSI_MLQUEUE_TARGET_BUSY; > > qc24_fail_command: > - spin_lock_irq(vha->host->host_lock); > - done(cmd); > + cmd->scsi_done(cmd); > > return 0; > } > > -static DEF_SCSI_QCMD(qla2xxx_queuecommand) > - > > /* > * qla2x00_eh_wait_on_command > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/