From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Williams Subject: [PATCH v4 1/2] libsas: pre-clean commands that won the eh vs completion race Date: Mon, 09 Jan 2012 23:38:31 -0800 Message-ID: <20120110073831.4563.41506.stgit@localhost6.localdomain6> References: <20120110073647.4563.7504.stgit@localhost6.localdomain6> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120110073647.4563.7504.stgit@localhost6.localdomain6> Sender: linux-scsi-owner@vger.kernel.org To: linux-scsi@vger.kernel.org Cc: linux-ide@vger.kernel.org, jack_wang@usish.com List-Id: linux-ide@vger.kernel.org When scrolling forward through the eh list (in a clear_q scenario) it is possible to encounter commands that won the completion vs eh race. Rather than sprinkle more "if (!task)" throughout the handler just make a pass through the list and delete the race winners before handling the rest. Signed-off-by: Dan Williams --- drivers/scsi/libsas/sas_scsi_host.c | 25 ++++++++++++++++--------- 1 files changed, 16 insertions(+), 9 deletions(-) diff --git a/drivers/scsi/libsas/sas_scsi_host.c b/drivers/scsi/libsas/sas_scsi_host.c index 94ef763..731c892 100644 --- a/drivers/scsi/libsas/sas_scsi_host.c +++ b/drivers/scsi/libsas/sas_scsi_host.c @@ -249,8 +249,8 @@ out_done: static void sas_eh_finish_cmd(struct scsi_cmnd *cmd) { - struct sas_task *task = TO_SAS_TASK(cmd); struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(cmd->device->host); + struct sas_task *task = TO_SAS_TASK(cmd); /* At this point, we only get called following an actual abort * of the task, so we should be guaranteed not to be racing with @@ -267,9 +267,9 @@ static void sas_eh_finish_cmd(struct scsi_cmnd *cmd) static void sas_eh_defer_cmd(struct scsi_cmnd *cmd) { - struct sas_task *task = TO_SAS_TASK(cmd); - struct domain_device *dev = task->dev; + struct domain_device *dev = cmd_to_domain_dev(cmd); struct sas_ha_struct *ha = dev->port->ha; + struct sas_task *task = TO_SAS_TASK(cmd); if (!dev_is_sata(dev)) { sas_eh_finish_cmd(cmd); @@ -530,8 +530,9 @@ static int sas_eh_handle_sas_errors(struct Scsi_Host *shost, struct sas_internal *i = to_sas_internal(shost->transportt); unsigned long flags; struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost); + LIST_HEAD(done); -Again: + /* clean out any commands that won the completion vs eh race */ list_for_each_entry_safe(cmd, n, work_q, eh_entry) { struct domain_device *dev = cmd_to_domain_dev(cmd); struct sas_task *task; @@ -545,7 +546,12 @@ Again: spin_unlock_irqrestore(&dev->done_lock, flags); if (!task) - continue; + list_move_tail(&cmd->eh_entry, &done); + } + + Again: + list_for_each_entry_safe(cmd, n, work_q, eh_entry) { + struct sas_task *task = TO_SAS_TASK(cmd); list_del_init(&cmd->eh_entry); @@ -649,15 +655,16 @@ Again: goto clear_q; } } + out: + list_splice_tail(&done, work_q); list_splice_tail_init(&ha->eh_ata_q, work_q); return list_empty(work_q); -clear_q: + + clear_q: SAS_DPRINTK("--- Exit %s -- clear_q\n", __func__); list_for_each_entry_safe(cmd, n, work_q, eh_entry) sas_eh_finish_cmd(cmd); - - list_splice_tail_init(&ha->eh_ata_q, work_q); - return list_empty(work_q); + goto out; } void sas_scsi_recover_host(struct Scsi_Host *shost)