From e494f6a728394ab0df194342549ee20e6f0752df Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Mon, 11 Nov 2013 13:44:54 +0100 Subject: [PATCH] [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 Signed-off-by: James Bottomley --- drivers/scsi/hosts.c | 14 +++- drivers/scsi/scsi.c | 3 + drivers/scsi/scsi_error.c | 151 ++++++++++++++++++++++++++++++++++---- drivers/scsi/scsi_priv.h | 2 + include/scsi/scsi_cmnd.h | 1 + include/scsi/scsi_host.h | 10 +++ 6 files changed, 167 insertions(+), 14 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index f2c5005f312a..c3ab093dd8a7 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -169,6 +169,7 @@ void scsi_remove_host(struct Scsi_Host *shost) spin_unlock_irqrestore(shost->host_lock, flags); scsi_autopm_get_host(shost); + flush_workqueue(shost->tmf_work_q); scsi_forget_host(shost); mutex_unlock(&shost->scan_mutex); scsi_proc_host_rm(shost); @@ -294,6 +295,8 @@ static void scsi_host_dev_release(struct device *dev) scsi_proc_hostdir_rm(shost->hostt); + if (shost->tmf_work_q) + destroy_workqueue(shost->tmf_work_q); if (shost->ehandler) kthread_stop(shost->ehandler); if (shost->work_q) @@ -360,7 +363,6 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) INIT_LIST_HEAD(&shost->eh_cmd_q); INIT_LIST_HEAD(&shost->starved_list); init_waitqueue_head(&shost->host_wait); - mutex_init(&shost->scan_mutex); /* @@ -444,9 +446,19 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize) goto fail_kfree; } + shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d", + WQ_UNBOUND | WQ_MEM_RECLAIM, + 1, shost->host_no); + if (!shost->tmf_work_q) { + printk(KERN_WARNING "scsi%d: failed to create tmf workq\n", + shost->host_no); + goto fail_kthread; + } scsi_proc_hostdir_add(shost->hostt); return shost; + fail_kthread: + kthread_stop(shost->ehandler); fail_kfree: kfree(shost); return NULL; diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index fe0bcb18fb26..2b04a57e0f4f 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -297,6 +297,7 @@ struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask) cmd->device = dev; INIT_LIST_HEAD(&cmd->list); + INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler); spin_lock_irqsave(&dev->list_lock, flags); list_add_tail(&cmd->list, &dev->cmd_list); spin_unlock_irqrestore(&dev->list_lock, flags); @@ -353,6 +354,8 @@ void scsi_put_command(struct scsi_cmnd *cmd) list_del_init(&cmd->list); spin_unlock_irqrestore(&cmd->device->list_lock, flags); + cancel_delayed_work(&cmd->abort_work); + __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev); } EXPORT_SYMBOL(scsi_put_command); diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 67c001457cb8..3dd04026d466 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -53,6 +53,8 @@ static void scsi_eh_done(struct scsi_cmnd *scmd); #define HOST_RESET_SETTLE_TIME (10) static int scsi_eh_try_stu(struct scsi_cmnd *scmd); +static int scsi_try_to_abort_cmd(struct scsi_host_template *, + struct scsi_cmnd *); /* called with shost->host_lock held */ void scsi_eh_wakeup(struct Scsi_Host *shost) @@ -99,6 +101,116 @@ static int scsi_host_eh_past_deadline(struct Scsi_Host *shost) return 1; } +/** + * scmd_eh_abort_handler - Handle command aborts + * @work: command to be aborted. + */ +void +scmd_eh_abort_handler(struct work_struct *work) +{ + struct scsi_cmnd *scmd = + container_of(work, struct scsi_cmnd, abort_work.work); + struct scsi_device *sdev = scmd->device; + unsigned long flags; + int rtn; + + spin_lock_irqsave(sdev->host->host_lock, flags); + if (scsi_host_eh_past_deadline(sdev->host)) { + spin_unlock_irqrestore(sdev->host->host_lock, flags); + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "scmd %p eh timeout, not aborting\n", + scmd)); + } else { + spin_unlock_irqrestore(sdev->host->host_lock, flags); + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "aborting command %p\n", scmd)); + rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd); + if (rtn == SUCCESS) { + scmd->result |= DID_TIME_OUT << 16; + if (!scsi_noretry_cmd(scmd) && + (++scmd->retries <= scmd->allowed)) { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_WARNING, scmd, + "scmd %p retry " + "aborted command\n", scmd)); + scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY); + } else { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_WARNING, scmd, + "scmd %p finish " + "aborted command\n", scmd)); + scsi_finish_command(scmd); + } + return; + } + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "scmd %p abort failed, rtn %d\n", + scmd, rtn)); + } + + if (!scsi_eh_scmd_add(scmd, 0)) { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_WARNING, scmd, + "scmd %p terminate " + "aborted command\n", scmd)); + scmd->result |= DID_TIME_OUT << 16; + scsi_finish_command(scmd); + } +} + +/** + * scsi_abort_command - schedule a command abort + * @scmd: scmd to abort. + * + * We only need to abort commands after a command timeout + */ +static int +scsi_abort_command(struct scsi_cmnd *scmd) +{ + struct scsi_device *sdev = scmd->device; + struct Scsi_Host *shost = sdev->host; + unsigned long flags; + + if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) { + /* + * Retry after abort failed, escalate to next level. + */ + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "scmd %p previous abort failed\n", scmd)); + cancel_delayed_work(&scmd->abort_work); + return FAILED; + } + + /* + * Do not try a command abort if + * SCSI EH has already started. + */ + spin_lock_irqsave(shost->host_lock, flags); + if (scsi_host_in_recovery(shost)) { + spin_unlock_irqrestore(shost->host_lock, flags); + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "scmd %p not aborting, host in recovery\n", + scmd)); + return FAILED; + } + + if (shost->eh_deadline && !shost->last_reset) + shost->last_reset = jiffies; + spin_unlock_irqrestore(shost->host_lock, flags); + + scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED; + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "scmd %p abort scheduled\n", scmd)); + queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100); + return SUCCESS; +} + /** * scsi_eh_scmd_add - add scsi cmd to error handling. * @scmd: scmd to run eh on. @@ -125,6 +237,8 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag) shost->last_reset = jiffies; ret = 1; + if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) + eh_flag &= ~SCSI_EH_CANCEL_CMD; scmd->eh_eflags |= eh_flag; list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q); shost->host_failed++; @@ -161,6 +275,10 @@ enum blk_eh_timer_return scsi_times_out(struct request *req) else if (host->hostt->eh_timed_out) rtn = host->hostt->eh_timed_out(scmd); + if (rtn == BLK_EH_NOT_HANDLED && !host->hostt->no_async_abort) + if (scsi_abort_command(scmd) == SUCCESS) + return BLK_EH_NOT_HANDLED; + scmd->result |= DID_TIME_OUT << 16; if (unlikely(rtn == BLK_EH_NOT_HANDLED && @@ -1577,7 +1695,7 @@ static void scsi_eh_offline_sdevs(struct list_head *work_q, } /** - * scsi_noretry_cmd - determinte if command should be failed fast + * scsi_noretry_cmd - determine if command should be failed fast * @scmd: SCSI cmd to examine. */ int scsi_noretry_cmd(struct scsi_cmnd *scmd) @@ -1585,6 +1703,8 @@ int scsi_noretry_cmd(struct scsi_cmnd *scmd) switch (host_byte(scmd->result)) { case DID_OK: break; + case DID_TIME_OUT: + goto check_type; case DID_BUS_BUSY: return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT); case DID_PARITY: @@ -1598,18 +1718,19 @@ int scsi_noretry_cmd(struct scsi_cmnd *scmd) return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER); } - switch (status_byte(scmd->result)) { - case CHECK_CONDITION: - /* - * assume caller has checked sense and determinted - * the check condition was retryable. - */ - if (scmd->request->cmd_flags & REQ_FAILFAST_DEV || - scmd->request->cmd_type == REQ_TYPE_BLOCK_PC) - return 1; - } + if (status_byte(scmd->result) != CHECK_CONDITION) + return 0; - return 0; +check_type: + /* + * assume caller has checked sense and determined + * the check condition was retryable. + */ + if (scmd->request->cmd_flags & REQ_FAILFAST_DEV || + scmd->request->cmd_type == REQ_TYPE_BLOCK_PC) + return 1; + else + return 0; } /** @@ -1659,9 +1780,13 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd) * looks good. drop through, and check the next byte. */ break; + case DID_ABORT: + if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) { + scmd->result |= DID_TIME_OUT << 16; + return SUCCESS; + } case DID_NO_CONNECT: case DID_BAD_TARGET: - case DID_ABORT: /* * note - this means that we just report the status back * to the top level driver, not that we actually think diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h index 8f9a0cadc296..f079a598bed4 100644 --- a/drivers/scsi/scsi_priv.h +++ b/drivers/scsi/scsi_priv.h @@ -19,6 +19,7 @@ struct scsi_nl_hdr; * Scsi Error Handler Flags */ #define SCSI_EH_CANCEL_CMD 0x0001 /* Cancel this cmd */ +#define SCSI_EH_ABORT_SCHEDULED 0x0002 /* Abort has been scheduled */ #define SCSI_SENSE_VALID(scmd) \ (((scmd)->sense_buffer[0] & 0x70) == 0x70) @@ -66,6 +67,7 @@ extern int __init scsi_init_devinfo(void); extern void scsi_exit_devinfo(void); /* scsi_error.c */ +extern void scmd_eh_abort_handler(struct work_struct *work); extern enum blk_eh_timer_return scsi_times_out(struct request *req); extern int scsi_error_handler(void *host); extern int scsi_decide_disposition(struct scsi_cmnd *cmd); diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h index de5f5d8f1f8a..91558a1f97f4 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -55,6 +55,7 @@ struct scsi_cmnd { struct scsi_device *device; struct list_head list; /* scsi_cmnd participates in queue lists */ struct list_head eh_entry; /* entry for the host eh_cmd_q */ + struct delayed_work abort_work; int eh_eflags; /* Used by error handlr */ /* diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index fe3b58e836c8..53075e5039e6 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -478,6 +478,11 @@ struct scsi_host_template { /* True if the controller does not support WRITE SAME */ unsigned no_write_same:1; + /* + * True if asynchronous aborts are not supported + */ + unsigned no_async_abort:1; + /* * Countdown for host blocking with no commands outstanding. */ @@ -689,6 +694,11 @@ struct Scsi_Host { char work_q_name[20]; struct workqueue_struct *work_q; + /* + * Task management function work queue + */ + struct workqueue_struct *tmf_work_q; + /* * Host has rejected a command because it was busy. */ -- 2.20.1