[SCSI] improved eh timeout handler
When a command runs into a timeout we need to send an 'ABORT TASK' TMF. This is typically done by the 'eh_abort_handler' LLDD callback. Conceptually, however, this function is a normal SCSI command, so there is no need to enter the error handler. This patch implements a new scsi_abort_command() function which invokes an asynchronous function scsi_eh_abort_handler() to abort the commands via the usual 'eh_abort_handler'. If abort succeeds the command is either retried or terminated, depending on the number of allowed retries. However, 'eh_eflags' records the abort, so if the retry would fail again the command is pushed onto the error handler without trying to abort it (again); it'll be cleared up from SCSI EH. [hare: smatch detected stray switch fixed] Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Родитель
2451079bc2
Коммит
e494f6a728
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@ -169,6 +169,7 @@ void scsi_remove_host(struct Scsi_Host *shost)
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spin_unlock_irqrestore(shost->host_lock, flags);
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scsi_autopm_get_host(shost);
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flush_workqueue(shost->tmf_work_q);
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scsi_forget_host(shost);
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mutex_unlock(&shost->scan_mutex);
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scsi_proc_host_rm(shost);
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@ -294,6 +295,8 @@ static void scsi_host_dev_release(struct device *dev)
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scsi_proc_hostdir_rm(shost->hostt);
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if (shost->tmf_work_q)
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destroy_workqueue(shost->tmf_work_q);
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if (shost->ehandler)
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kthread_stop(shost->ehandler);
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if (shost->work_q)
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@ -360,7 +363,6 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
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INIT_LIST_HEAD(&shost->eh_cmd_q);
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INIT_LIST_HEAD(&shost->starved_list);
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init_waitqueue_head(&shost->host_wait);
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mutex_init(&shost->scan_mutex);
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/*
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@ -444,9 +446,19 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
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goto fail_kfree;
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}
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shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
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WQ_UNBOUND | WQ_MEM_RECLAIM,
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1, shost->host_no);
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if (!shost->tmf_work_q) {
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printk(KERN_WARNING "scsi%d: failed to create tmf workq\n",
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shost->host_no);
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goto fail_kthread;
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}
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scsi_proc_hostdir_add(shost->hostt);
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return shost;
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fail_kthread:
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kthread_stop(shost->ehandler);
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fail_kfree:
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kfree(shost);
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return NULL;
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@ -297,6 +297,7 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
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cmd->device = dev;
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INIT_LIST_HEAD(&cmd->list);
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INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
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spin_lock_irqsave(&dev->list_lock, flags);
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list_add_tail(&cmd->list, &dev->cmd_list);
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spin_unlock_irqrestore(&dev->list_lock, flags);
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@ -353,6 +354,8 @@ void scsi_put_command(struct scsi_cmnd *cmd)
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list_del_init(&cmd->list);
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spin_unlock_irqrestore(&cmd->device->list_lock, flags);
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cancel_delayed_work(&cmd->abort_work);
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__scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
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}
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EXPORT_SYMBOL(scsi_put_command);
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@ -53,6 +53,8 @@ static void scsi_eh_done(struct scsi_cmnd *scmd);
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#define HOST_RESET_SETTLE_TIME (10)
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static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
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static int scsi_try_to_abort_cmd(struct scsi_host_template *,
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struct scsi_cmnd *);
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/* called with shost->host_lock held */
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void scsi_eh_wakeup(struct Scsi_Host *shost)
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@ -99,6 +101,116 @@ static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
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return 1;
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}
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/**
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* scmd_eh_abort_handler - Handle command aborts
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* @work: command to be aborted.
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*/
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void
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scmd_eh_abort_handler(struct work_struct *work)
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{
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struct scsi_cmnd *scmd =
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container_of(work, struct scsi_cmnd, abort_work.work);
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struct scsi_device *sdev = scmd->device;
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unsigned long flags;
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int rtn;
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spin_lock_irqsave(sdev->host->host_lock, flags);
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if (scsi_host_eh_past_deadline(sdev->host)) {
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spin_unlock_irqrestore(sdev->host->host_lock, flags);
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SCSI_LOG_ERROR_RECOVERY(3,
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scmd_printk(KERN_INFO, scmd,
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"scmd %p eh timeout, not aborting\n",
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scmd));
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} else {
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spin_unlock_irqrestore(sdev->host->host_lock, flags);
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SCSI_LOG_ERROR_RECOVERY(3,
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scmd_printk(KERN_INFO, scmd,
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"aborting command %p\n", scmd));
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rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
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if (rtn == SUCCESS) {
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scmd->result |= DID_TIME_OUT << 16;
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if (!scsi_noretry_cmd(scmd) &&
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(++scmd->retries <= scmd->allowed)) {
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SCSI_LOG_ERROR_RECOVERY(3,
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scmd_printk(KERN_WARNING, scmd,
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"scmd %p retry "
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"aborted command\n", scmd));
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scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
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} else {
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SCSI_LOG_ERROR_RECOVERY(3,
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scmd_printk(KERN_WARNING, scmd,
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"scmd %p finish "
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"aborted command\n", scmd));
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scsi_finish_command(scmd);
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}
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return;
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}
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SCSI_LOG_ERROR_RECOVERY(3,
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scmd_printk(KERN_INFO, scmd,
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"scmd %p abort failed, rtn %d\n",
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scmd, rtn));
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}
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if (!scsi_eh_scmd_add(scmd, 0)) {
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SCSI_LOG_ERROR_RECOVERY(3,
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scmd_printk(KERN_WARNING, scmd,
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"scmd %p terminate "
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"aborted command\n", scmd));
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scmd->result |= DID_TIME_OUT << 16;
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scsi_finish_command(scmd);
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}
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}
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/**
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* scsi_abort_command - schedule a command abort
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* @scmd: scmd to abort.
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*
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* We only need to abort commands after a command timeout
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*/
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static int
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scsi_abort_command(struct scsi_cmnd *scmd)
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{
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struct scsi_device *sdev = scmd->device;
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struct Scsi_Host *shost = sdev->host;
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unsigned long flags;
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if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
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/*
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* Retry after abort failed, escalate to next level.
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*/
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SCSI_LOG_ERROR_RECOVERY(3,
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scmd_printk(KERN_INFO, scmd,
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"scmd %p previous abort failed\n", scmd));
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cancel_delayed_work(&scmd->abort_work);
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return FAILED;
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}
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/*
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* Do not try a command abort if
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* SCSI EH has already started.
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*/
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spin_lock_irqsave(shost->host_lock, flags);
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if (scsi_host_in_recovery(shost)) {
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spin_unlock_irqrestore(shost->host_lock, flags);
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SCSI_LOG_ERROR_RECOVERY(3,
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scmd_printk(KERN_INFO, scmd,
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"scmd %p not aborting, host in recovery\n",
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scmd));
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return FAILED;
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}
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if (shost->eh_deadline && !shost->last_reset)
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shost->last_reset = jiffies;
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spin_unlock_irqrestore(shost->host_lock, flags);
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scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
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SCSI_LOG_ERROR_RECOVERY(3,
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scmd_printk(KERN_INFO, scmd,
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"scmd %p abort scheduled\n", scmd));
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queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
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return SUCCESS;
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}
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/**
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* scsi_eh_scmd_add - add scsi cmd to error handling.
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* @scmd: scmd to run eh on.
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@ -125,6 +237,8 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
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shost->last_reset = jiffies;
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ret = 1;
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if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
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eh_flag &= ~SCSI_EH_CANCEL_CMD;
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scmd->eh_eflags |= eh_flag;
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list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
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shost->host_failed++;
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@ -161,6 +275,10 @@ enum blk_eh_timer_return scsi_times_out(struct request *req)
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else if (host->hostt->eh_timed_out)
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rtn = host->hostt->eh_timed_out(scmd);
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if (rtn == BLK_EH_NOT_HANDLED && !host->hostt->no_async_abort)
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if (scsi_abort_command(scmd) == SUCCESS)
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return BLK_EH_NOT_HANDLED;
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scmd->result |= DID_TIME_OUT << 16;
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if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
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@ -1577,7 +1695,7 @@ static void scsi_eh_offline_sdevs(struct list_head *work_q,
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}
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/**
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* scsi_noretry_cmd - determinte if command should be failed fast
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* scsi_noretry_cmd - determine if command should be failed fast
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* @scmd: SCSI cmd to examine.
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*/
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int scsi_noretry_cmd(struct scsi_cmnd *scmd)
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@ -1585,6 +1703,8 @@ int scsi_noretry_cmd(struct scsi_cmnd *scmd)
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switch (host_byte(scmd->result)) {
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case DID_OK:
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break;
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case DID_TIME_OUT:
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goto check_type;
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case DID_BUS_BUSY:
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return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
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case DID_PARITY:
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@ -1598,18 +1718,19 @@ int scsi_noretry_cmd(struct scsi_cmnd *scmd)
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return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
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}
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switch (status_byte(scmd->result)) {
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case CHECK_CONDITION:
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/*
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* assume caller has checked sense and determinted
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* the check condition was retryable.
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*/
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if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
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scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
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return 1;
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}
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if (status_byte(scmd->result) != CHECK_CONDITION)
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return 0;
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return 0;
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check_type:
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/*
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* assume caller has checked sense and determined
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* the check condition was retryable.
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*/
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if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
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scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
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return 1;
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else
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return 0;
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}
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/**
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@ -1659,9 +1780,13 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
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* looks good. drop through, and check the next byte.
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*/
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break;
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case DID_ABORT:
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if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
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scmd->result |= DID_TIME_OUT << 16;
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return SUCCESS;
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}
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case DID_NO_CONNECT:
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case DID_BAD_TARGET:
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case DID_ABORT:
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/*
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* note - this means that we just report the status back
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* to the top level driver, not that we actually think
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@ -19,6 +19,7 @@ struct scsi_nl_hdr;
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* Scsi Error Handler Flags
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*/
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#define SCSI_EH_CANCEL_CMD 0x0001 /* Cancel this cmd */
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#define SCSI_EH_ABORT_SCHEDULED 0x0002 /* Abort has been scheduled */
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#define SCSI_SENSE_VALID(scmd) \
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(((scmd)->sense_buffer[0] & 0x70) == 0x70)
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@ -66,6 +67,7 @@ extern int __init scsi_init_devinfo(void);
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extern void scsi_exit_devinfo(void);
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/* scsi_error.c */
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extern void scmd_eh_abort_handler(struct work_struct *work);
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extern enum blk_eh_timer_return scsi_times_out(struct request *req);
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extern int scsi_error_handler(void *host);
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extern int scsi_decide_disposition(struct scsi_cmnd *cmd);
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@ -55,6 +55,7 @@ struct scsi_cmnd {
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struct scsi_device *device;
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struct list_head list; /* scsi_cmnd participates in queue lists */
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struct list_head eh_entry; /* entry for the host eh_cmd_q */
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struct delayed_work abort_work;
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int eh_eflags; /* Used by error handlr */
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/*
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@ -478,6 +478,11 @@ struct scsi_host_template {
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/* True if the controller does not support WRITE SAME */
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unsigned no_write_same:1;
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/*
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* True if asynchronous aborts are not supported
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*/
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unsigned no_async_abort:1;
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/*
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* Countdown for host blocking with no commands outstanding.
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*/
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@ -689,6 +694,11 @@ struct Scsi_Host {
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char work_q_name[20];
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struct workqueue_struct *work_q;
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/*
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* Task management function work queue
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*/
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struct workqueue_struct *tmf_work_q;
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/*
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* Host has rejected a command because it was busy.
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*/
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