/* * scsi_error.c Copyright (C) 1997 Eric Youngdale * * SCSI error/timeout handling * Initial versions: Eric Youngdale. Based upon conversations with * Leonard Zubkoff and David Miller at Linux Expo, * ideas originating from all over the place. * * Restructured scsi_unjam_host and associated functions. * September 04, 2002 Mike Anderson (andmike@us.ibm.com) * * Forward port of Russell King's (rmk@arm.linux.org.uk) changes and * minor cleanups. * September 30, 2002 Mike Anderson (andmike@us.ibm.com) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "scsi_priv.h" #include "scsi_logging.h" #include "scsi_transport_api.h" #include #define SENSE_TIMEOUT (10*HZ) /* * These should *probably* be handled by the host itself. * Since it is allowed to sleep, it probably should. */ #define BUS_RESET_SETTLE_TIME (10) #define HOST_RESET_SETTLE_TIME (10) static int scsi_eh_try_stu(struct scsi_cmnd *scmd); /* called with shost->host_lock held */ void scsi_eh_wakeup(struct Scsi_Host *shost) { if (shost->host_busy == shost->host_failed) { trace_scsi_eh_wakeup(shost); wake_up_process(shost->ehandler); SCSI_LOG_ERROR_RECOVERY(5, printk("Waking error handler thread\n")); } } /** * scsi_schedule_eh - schedule EH for SCSI host * @shost: SCSI host to invoke error handling on. * * Schedule SCSI EH without scmd. */ void scsi_schedule_eh(struct Scsi_Host *shost) { unsigned long flags; spin_lock_irqsave(shost->host_lock, flags); if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 || scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) { shost->host_eh_scheduled++; scsi_eh_wakeup(shost); } spin_unlock_irqrestore(shost->host_lock, flags); } EXPORT_SYMBOL_GPL(scsi_schedule_eh); /** * scsi_eh_scmd_add - add scsi cmd to error handling. * @scmd: scmd to run eh on. * @eh_flag: optional SCSI_EH flag. * * Return value: * 0 on failure. */ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag) { struct Scsi_Host *shost = scmd->device->host; unsigned long flags; int ret = 0; if (!shost->ehandler) return 0; spin_lock_irqsave(shost->host_lock, flags); if (scsi_host_set_state(shost, SHOST_RECOVERY)) if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) goto out_unlock; ret = 1; scmd->eh_eflags |= eh_flag; list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q); shost->host_failed++; scsi_eh_wakeup(shost); out_unlock: spin_unlock_irqrestore(shost->host_lock, flags); return ret; } /** * scsi_times_out - Timeout function for normal scsi commands. * @req: request that is timing out. * * Notes: * We do not need to lock this. There is the potential for a race * only in that the normal completion handling might run, but if the * normal completion function determines that the timer has already * fired, then it mustn't do anything. */ enum blk_eh_timer_return scsi_times_out(struct request *req) { struct scsi_cmnd *scmd = req->special; enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED; struct Scsi_Host *host = scmd->device->host; trace_scsi_dispatch_cmd_timeout(scmd); scsi_log_completion(scmd, TIMEOUT_ERROR); if (host->transportt->eh_timed_out) rtn = host->transportt->eh_timed_out(scmd); else if (host->hostt->eh_timed_out) rtn = host->hostt->eh_timed_out(scmd); if (unlikely(rtn == BLK_EH_NOT_HANDLED && !scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) { scmd->result |= DID_TIME_OUT << 16; rtn = BLK_EH_HANDLED; } return rtn; } /** * scsi_block_when_processing_errors - Prevent cmds from being queued. * @sdev: Device on which we are performing recovery. * * Description: * We block until the host is out of error recovery, and then check to * see whether the host or the device is offline. * * Return value: * 0 when dev was taken offline by error recovery. 1 OK to proceed. */ int scsi_block_when_processing_errors(struct scsi_device *sdev) { int online; wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host)); online = scsi_device_online(sdev); SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __func__, online)); return online; } EXPORT_SYMBOL(scsi_block_when_processing_errors); #ifdef CONFIG_SCSI_LOGGING /** * scsi_eh_prt_fail_stats - Log info on failures. * @shost: scsi host being recovered. * @work_q: Queue of scsi cmds to process. */ static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost, struct list_head *work_q) { struct scsi_cmnd *scmd; struct scsi_device *sdev; int total_failures = 0; int cmd_failed = 0; int cmd_cancel = 0; int devices_failed = 0; shost_for_each_device(sdev, shost) { list_for_each_entry(scmd, work_q, eh_entry) { if (scmd->device == sdev) { ++total_failures; if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ++cmd_cancel; else ++cmd_failed; } } if (cmd_cancel || cmd_failed) { SCSI_LOG_ERROR_RECOVERY(3, sdev_printk(KERN_INFO, sdev, "%s: cmds failed: %d, cancel: %d\n", __func__, cmd_failed, cmd_cancel)); cmd_cancel = 0; cmd_failed = 0; ++devices_failed; } } SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d" " devices require eh work\n", total_failures, devices_failed)); } #endif /** * scsi_check_sense - Examine scsi cmd sense * @scmd: Cmd to have sense checked. * * Return value: * SUCCESS or FAILED or NEEDS_RETRY or TARGET_ERROR * * Notes: * When a deferred error is detected the current command has * not been executed and needs retrying. */ static int scsi_check_sense(struct scsi_cmnd *scmd) { struct scsi_device *sdev = scmd->device; struct scsi_sense_hdr sshdr; if (! scsi_command_normalize_sense(scmd, &sshdr)) return FAILED; /* no valid sense data */ if (scsi_sense_is_deferred(&sshdr)) return NEEDS_RETRY; if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh && sdev->scsi_dh_data->scsi_dh->check_sense) { int rc; rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr); if (rc != SCSI_RETURN_NOT_HANDLED) return rc; /* handler does not care. Drop down to default handling */ } /* * Previous logic looked for FILEMARK, EOM or ILI which are * mainly associated with tapes and returned SUCCESS. */ if (sshdr.response_code == 0x70) { /* fixed format */ if (scmd->sense_buffer[2] & 0xe0) return SUCCESS; } else { /* * descriptor format: look for "stream commands sense data * descriptor" (see SSC-3). Assume single sense data * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG. */ if ((sshdr.additional_length > 3) && (scmd->sense_buffer[8] == 0x4) && (scmd->sense_buffer[11] & 0xe0)) return SUCCESS; } switch (sshdr.sense_key) { case NO_SENSE: return SUCCESS; case RECOVERED_ERROR: return /* soft_error */ SUCCESS; case ABORTED_COMMAND: if (sshdr.asc == 0x10) /* DIF */ return SUCCESS; return NEEDS_RETRY; case NOT_READY: case UNIT_ATTENTION: /* * if we are expecting a cc/ua because of a bus reset that we * performed, treat this just as a retry. otherwise this is * information that we should pass up to the upper-level driver * so that we can deal with it there. */ if (scmd->device->expecting_cc_ua) { /* * Because some device does not queue unit * attentions correctly, we carefully check * additional sense code and qualifier so as * not to squash media change unit attention. */ if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) { scmd->device->expecting_cc_ua = 0; return NEEDS_RETRY; } } /* * if the device is in the process of becoming ready, we * should retry. */ if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01)) return NEEDS_RETRY; /* * if the device is not started, we need to wake * the error handler to start the motor */ if (scmd->device->allow_restart && (sshdr.asc == 0x04) && (sshdr.ascq == 0x02)) return FAILED; if (sshdr.asc == 0x3f && sshdr.ascq == 0x0e) scmd_printk(KERN_WARNING, scmd, "Warning! Received an indication that the " "LUN assignments on this target have " "changed. The Linux SCSI layer does not " "automatically remap LUN assignments.\n"); else if (sshdr.asc == 0x3f) scmd_printk(KERN_WARNING, scmd, "Warning! Received an indication that the " "operating parameters on this target have " "changed. The Linux SCSI layer does not " "automatically adjust these parameters.\n"); if (sshdr.asc == 0x38 && sshdr.ascq == 0x07) scmd_printk(KERN_WARNING, scmd, "Warning! Received an indication that the " "LUN reached a thin provisioning soft " "threshold.\n"); /* * Pass the UA upwards for a determination in the completion * functions. */ return SUCCESS; /* these are not supported */ case COPY_ABORTED: case VOLUME_OVERFLOW: case MISCOMPARE: case BLANK_CHECK: case DATA_PROTECT: return TARGET_ERROR; case MEDIUM_ERROR: if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */ sshdr.asc == 0x13 || /* AMNF DATA FIELD */ sshdr.asc == 0x14) { /* RECORD NOT FOUND */ return TARGET_ERROR; } return NEEDS_RETRY; case HARDWARE_ERROR: if (scmd->device->retry_hwerror) return ADD_TO_MLQUEUE; else return TARGET_ERROR; case ILLEGAL_REQUEST: default: return SUCCESS; } } static void scsi_handle_queue_ramp_up(struct scsi_device *sdev) { struct scsi_host_template *sht = sdev->host->hostt; struct scsi_device *tmp_sdev; if (!sht->change_queue_depth || sdev->queue_depth >= sdev->max_queue_depth) return; if (time_before(jiffies, sdev->last_queue_ramp_up + sdev->queue_ramp_up_period)) return; if (time_before(jiffies, sdev->last_queue_full_time + sdev->queue_ramp_up_period)) return; /* * Walk all devices of a target and do * ramp up on them. */ shost_for_each_device(tmp_sdev, sdev->host) { if (tmp_sdev->channel != sdev->channel || tmp_sdev->id != sdev->id || tmp_sdev->queue_depth == sdev->max_queue_depth) continue; /* * call back into LLD to increase queue_depth by one * with ramp up reason code. */ sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1, SCSI_QDEPTH_RAMP_UP); sdev->last_queue_ramp_up = jiffies; } } static void scsi_handle_queue_full(struct scsi_device *sdev) { struct scsi_host_template *sht = sdev->host->hostt; struct scsi_device *tmp_sdev; if (!sht->change_queue_depth) return; shost_for_each_device(tmp_sdev, sdev->host) { if (tmp_sdev->channel != sdev->channel || tmp_sdev->id != sdev->id) continue; /* * We do not know the number of commands that were at * the device when we got the queue full so we start * from the highest possible value and work our way down. */ sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1, SCSI_QDEPTH_QFULL); } } /** * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD. * @scmd: SCSI cmd to examine. * * Notes: * This is *only* called when we are examining the status of commands * queued during error recovery. the main difference here is that we * don't allow for the possibility of retries here, and we are a lot * more restrictive about what we consider acceptable. */ static int scsi_eh_completed_normally(struct scsi_cmnd *scmd) { /* * first check the host byte, to see if there is anything in there * that would indicate what we need to do. */ if (host_byte(scmd->result) == DID_RESET) { /* * rats. we are already in the error handler, so we now * get to try and figure out what to do next. if the sense * is valid, we have a pretty good idea of what to do. * if not, we mark it as FAILED. */ return scsi_check_sense(scmd); } if (host_byte(scmd->result) != DID_OK) return FAILED; /* * next, check the message byte. */ if (msg_byte(scmd->result) != COMMAND_COMPLETE) return FAILED; /* * now, check the status byte to see if this indicates * anything special. */ switch (status_byte(scmd->result)) { case GOOD: scsi_handle_queue_ramp_up(scmd->device); case COMMAND_TERMINATED: return SUCCESS; case CHECK_CONDITION: return scsi_check_sense(scmd); case CONDITION_GOOD: case INTERMEDIATE_GOOD: case INTERMEDIATE_C_GOOD: /* * who knows? FIXME(eric) */ return SUCCESS; case RESERVATION_CONFLICT: if (scmd->cmnd[0] == TEST_UNIT_READY) /* it is a success, we probed the device and * found it */ return SUCCESS; /* otherwise, we failed to send the command */ return FAILED; case QUEUE_FULL: scsi_handle_queue_full(scmd->device); /* fall through */ case BUSY: return NEEDS_RETRY; default: return FAILED; } return FAILED; } /** * scsi_eh_done - Completion function for error handling. * @scmd: Cmd that is done. */ static void scsi_eh_done(struct scsi_cmnd *scmd) { struct completion *eh_action; SCSI_LOG_ERROR_RECOVERY(3, printk("%s scmd: %p result: %x\n", __func__, scmd, scmd->result)); eh_action = scmd->device->host->eh_action; if (eh_action) complete(eh_action); } /** * scsi_try_host_reset - ask host adapter to reset itself * @scmd: SCSI cmd to send hsot reset. */ static int scsi_try_host_reset(struct scsi_cmnd *scmd) { unsigned long flags; int rtn; struct Scsi_Host *host = scmd->device->host; struct scsi_host_template *hostt = host->hostt; SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n", __func__)); if (!hostt->eh_host_reset_handler) return FAILED; rtn = hostt->eh_host_reset_handler(scmd); if (rtn == SUCCESS) { if (!hostt->skip_settle_delay) ssleep(HOST_RESET_SETTLE_TIME); spin_lock_irqsave(host->host_lock, flags); scsi_report_bus_reset(host, scmd_channel(scmd)); spin_unlock_irqrestore(host->host_lock, flags); } return rtn; } /** * scsi_try_bus_reset - ask host to perform a bus reset * @scmd: SCSI cmd to send bus reset. */ static int scsi_try_bus_reset(struct scsi_cmnd *scmd) { unsigned long flags; int rtn; struct Scsi_Host *host = scmd->device->host; struct scsi_host_template *hostt = host->hostt; SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n", __func__)); if (!hostt->eh_bus_reset_handler) return FAILED; rtn = hostt->eh_bus_reset_handler(scmd); if (rtn == SUCCESS) { if (!hostt->skip_settle_delay) ssleep(BUS_RESET_SETTLE_TIME); spin_lock_irqsave(host->host_lock, flags); scsi_report_bus_reset(host, scmd_channel(scmd)); spin_unlock_irqrestore(host->host_lock, flags); } return rtn; } static void __scsi_report_device_reset(struct scsi_device *sdev, void *data) { sdev->was_reset = 1; sdev->expecting_cc_ua = 1; } /** * scsi_try_target_reset - Ask host to perform a target reset * @scmd: SCSI cmd used to send a target reset * * Notes: * There is no timeout for this operation. if this operation is * unreliable for a given host, then the host itself needs to put a * timer on it, and set the host back to a consistent state prior to * returning. */ static int scsi_try_target_reset(struct scsi_cmnd *scmd) { unsigned long flags; int rtn; struct Scsi_Host *host = scmd->device->host; struct scsi_host_template *hostt = host->hostt; if (!hostt->eh_target_reset_handler) return FAILED; rtn = hostt->eh_target_reset_handler(scmd); if (rtn == SUCCESS) { spin_lock_irqsave(host->host_lock, flags); __starget_for_each_device(scsi_target(scmd->device), NULL, __scsi_report_device_reset); spin_unlock_irqrestore(host->host_lock, flags); } return rtn; } /** * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev * @scmd: SCSI cmd used to send BDR * * Notes: * There is no timeout for this operation. if this operation is * unreliable for a given host, then the host itself needs to put a * timer on it, and set the host back to a consistent state prior to * returning. */ static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd) { int rtn; struct scsi_host_template *hostt = scmd->device->host->hostt; if (!hostt->eh_device_reset_handler) return FAILED; rtn = hostt->eh_device_reset_handler(scmd); if (rtn == SUCCESS) __scsi_report_device_reset(scmd->device, NULL); return rtn; } static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd) { if (!hostt->eh_abort_handler) return FAILED; return hostt->eh_abort_handler(scmd); } static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd) { if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS) if (scsi_try_bus_device_reset(scmd) != SUCCESS) if (scsi_try_target_reset(scmd) != SUCCESS) if (scsi_try_bus_reset(scmd) != SUCCESS) scsi_try_host_reset(scmd); } /** * scsi_eh_prep_cmnd - Save a scsi command info as part of error recory * @scmd: SCSI command structure to hijack * @ses: structure to save restore information * @cmnd: CDB to send. Can be NULL if no new cmnd is needed * @cmnd_size: size in bytes of @cmnd (must be <= BLK_MAX_CDB) * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored) * * This function is used to save a scsi command information before re-execution * as part of the error recovery process. If @sense_bytes is 0 the command * sent must be one that does not transfer any data. If @sense_bytes != 0 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer. */ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses, unsigned char *cmnd, int cmnd_size, unsigned sense_bytes) { struct scsi_device *sdev = scmd->device; /* * We need saved copies of a number of fields - this is because * error handling may need to overwrite these with different values * to run different commands, and once error handling is complete, * we will need to restore these values prior to running the actual * command. */ ses->cmd_len = scmd->cmd_len; ses->cmnd = scmd->cmnd; ses->data_direction = scmd->sc_data_direction; ses->sdb = scmd->sdb; ses->next_rq = scmd->request->next_rq; ses->result = scmd->result; ses->underflow = scmd->underflow; ses->prot_op = scmd->prot_op; scmd->prot_op = SCSI_PROT_NORMAL; scmd->cmnd = ses->eh_cmnd; memset(scmd->cmnd, 0, BLK_MAX_CDB); memset(&scmd->sdb, 0, sizeof(scmd->sdb)); scmd->request->next_rq = NULL; if (sense_bytes) { scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE, sense_bytes); sg_init_one(&ses->sense_sgl, scmd->sense_buffer, scmd->sdb.length); scmd->sdb.table.sgl = &ses->sense_sgl; scmd->sc_data_direction = DMA_FROM_DEVICE; scmd->sdb.table.nents = 1; scmd->cmnd[0] = REQUEST_SENSE; scmd->cmnd[4] = scmd->sdb.length; scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]); } else { scmd->sc_data_direction = DMA_NONE; if (cmnd) { BUG_ON(cmnd_size > BLK_MAX_CDB); memcpy(scmd->cmnd, cmnd, cmnd_size); scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]); } } scmd->underflow = 0; if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN) scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) | (sdev->lun << 5 & 0xe0); /* * Zero the sense buffer. The scsi spec mandates that any * untransferred sense data should be interpreted as being zero. */ memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); } EXPORT_SYMBOL(scsi_eh_prep_cmnd); /** * scsi_eh_restore_cmnd - Restore a scsi command info as part of error recory * @scmd: SCSI command structure to restore * @ses: saved information from a coresponding call to scsi_eh_prep_cmnd * * Undo any damage done by above scsi_eh_prep_cmnd(). */ void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses) { /* * Restore original data */ scmd->cmd_len = ses->cmd_len; scmd->cmnd = ses->cmnd; scmd->sc_data_direction = ses->data_direction; scmd->sdb = ses->sdb; scmd->request->next_rq = ses->next_rq; scmd->result = ses->result; scmd->underflow = ses->underflow; scmd->prot_op = ses->prot_op; } EXPORT_SYMBOL(scsi_eh_restore_cmnd); /** * scsi_send_eh_cmnd - submit a scsi command as part of error recory * @scmd: SCSI command structure to hijack * @cmnd: CDB to send * @cmnd_size: size in bytes of @cmnd * @timeout: timeout for this request * @sense_bytes: size of sense data to copy or 0 * * This function is used to send a scsi command down to a target device * as part of the error recovery process. See also scsi_eh_prep_cmnd() above. * * Return value: * SUCCESS or FAILED or NEEDS_RETRY */ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, int cmnd_size, int timeout, unsigned sense_bytes) { struct scsi_device *sdev = scmd->device; struct Scsi_Host *shost = sdev->host; DECLARE_COMPLETION_ONSTACK(done); unsigned long timeleft; struct scsi_eh_save ses; int rtn; scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes); shost->eh_action = &done; scsi_log_send(scmd); scmd->scsi_done = scsi_eh_done; shost->hostt->queuecommand(shost, scmd); timeleft = wait_for_completion_timeout(&done, timeout); shost->eh_action = NULL; scsi_log_completion(scmd, SUCCESS); SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd: %p, timeleft: %ld\n", __func__, scmd, timeleft)); /* * If there is time left scsi_eh_done got called, and we will * examine the actual status codes to see whether the command * actually did complete normally, else tell the host to forget * about this command. */ if (timeleft) { rtn = scsi_eh_completed_normally(scmd); SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scsi_eh_completed_normally %x\n", __func__, rtn)); switch (rtn) { case SUCCESS: case NEEDS_RETRY: case FAILED: case TARGET_ERROR: break; case ADD_TO_MLQUEUE: rtn = NEEDS_RETRY; break; default: rtn = FAILED; break; } } else { scsi_abort_eh_cmnd(scmd); rtn = FAILED; } scsi_eh_restore_cmnd(scmd, &ses); return rtn; } /** * scsi_request_sense - Request sense data from a particular target. * @scmd: SCSI cmd for request sense. * * Notes: * Some hosts automatically obtain this information, others require * that we obtain it on our own. This function will *not* return until * the command either times out, or it completes. */ static int scsi_request_sense(struct scsi_cmnd *scmd) { return scsi_send_eh_cmnd(scmd, NULL, 0, SENSE_TIMEOUT, ~0); } /** * scsi_eh_finish_cmd - Handle a cmd that eh is finished with. * @scmd: Original SCSI cmd that eh has finished. * @done_q: Queue for processed commands. * * Notes: * We don't want to use the normal command completion while we are are * still handling errors - it may cause other commands to be queued, * and that would disturb what we are doing. Thus we really want to * keep a list of pending commands for final completion, and once we * are ready to leave error handling we handle completion for real. */ void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q) { scmd->device->host->host_failed--; scmd->eh_eflags = 0; list_move_tail(&scmd->eh_entry, done_q); } EXPORT_SYMBOL(scsi_eh_finish_cmd); /** * scsi_eh_get_sense - Get device sense data. * @work_q: Queue of commands to process. * @done_q: Queue of processed commands. * * Description: * See if we need to request sense information. if so, then get it * now, so we have a better idea of what to do. * * Notes: * This has the unfortunate side effect that if a shost adapter does * not automatically request sense information, we end up shutting * it down before we request it. * * All drivers should request sense information internally these days, * so for now all I have to say is tough noogies if you end up in here. * * XXX: Long term this code should go away, but that needs an audit of * all LLDDs first. */ int scsi_eh_get_sense(struct list_head *work_q, struct list_head *done_q) { struct scsi_cmnd *scmd, *next; int rtn; list_for_each_entry_safe(scmd, next, work_q, eh_entry) { if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) || SCSI_SENSE_VALID(scmd)) continue; SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd, "%s: requesting sense\n", current->comm)); rtn = scsi_request_sense(scmd); if (rtn != SUCCESS) continue; SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p" " result %x\n", scmd, scmd->result)); SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd)); rtn = scsi_decide_disposition(scmd); /* * if the result was normal, then just pass it along to the * upper level. */ if (rtn == SUCCESS) /* we don't want this command reissued, just * finished with the sense data, so set * retries to the max allowed to ensure it * won't get reissued */ scmd->retries = scmd->allowed; else if (rtn != NEEDS_RETRY) continue; scsi_eh_finish_cmd(scmd, done_q); } return list_empty(work_q); } EXPORT_SYMBOL_GPL(scsi_eh_get_sense); /** * scsi_eh_tur - Send TUR to device. * @scmd: &scsi_cmnd to send TUR * * Return value: * 0 - Device is ready. 1 - Device NOT ready. */ static int scsi_eh_tur(struct scsi_cmnd *scmd) { static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0}; int retry_cnt = 1, rtn; retry_tur: rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, SENSE_TIMEOUT, 0); SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n", __func__, scmd, rtn)); switch (rtn) { case NEEDS_RETRY: if (retry_cnt--) goto retry_tur; /*FALLTHRU*/ case SUCCESS: return 0; default: return 1; } } /** * scsi_eh_test_devices - check if devices are responding from error recovery. * @cmd_list: scsi commands in error recovery. * @work_q: queue for commands which still need more error recovery * @done_q: queue for commands which are finished * @try_stu: boolean on if a STU command should be tried in addition to TUR. * * Decription: * Tests if devices are in a working state. Commands to devices now in * a working state are sent to the done_q while commands to devices which * are still failing to respond are returned to the work_q for more * processing. **/ static int scsi_eh_test_devices(struct list_head *cmd_list, struct list_head *work_q, struct list_head *done_q, int try_stu) { struct scsi_cmnd *scmd, *next; struct scsi_device *sdev; int finish_cmds; while (!list_empty(cmd_list)) { scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry); sdev = scmd->device; finish_cmds = !scsi_device_online(scmd->device) || (try_stu && !scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) || !scsi_eh_tur(scmd); list_for_each_entry_safe(scmd, next, cmd_list, eh_entry) if (scmd->device == sdev) { if (finish_cmds) scsi_eh_finish_cmd(scmd, done_q); else list_move_tail(&scmd->eh_entry, work_q); } } return list_empty(work_q); } /** * scsi_eh_abort_cmds - abort pending commands. * @work_q: &list_head for pending commands. * @done_q: &list_head for processed commands. * * Decription: * Try and see whether or not it makes sense to try and abort the * running command. This only works out to be the case if we have one * command that has timed out. If the command simply failed, it makes * no sense to try and abort the command, since as far as the shost * adapter is concerned, it isn't running. */ static int scsi_eh_abort_cmds(struct list_head *work_q, struct list_head *done_q) { struct scsi_cmnd *scmd, *next; LIST_HEAD(check_list); int rtn; list_for_each_entry_safe(scmd, next, work_q, eh_entry) { if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD)) continue; SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:" "0x%p\n", current->comm, scmd)); rtn = scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd); if (rtn == SUCCESS || rtn == FAST_IO_FAIL) { scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD; if (rtn == FAST_IO_FAIL) scsi_eh_finish_cmd(scmd, done_q); else list_move_tail(&scmd->eh_entry, &check_list); } else SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting" " cmd failed:" "0x%p\n", current->comm, scmd)); } return scsi_eh_test_devices(&check_list, work_q, done_q, 0); } /** * scsi_eh_try_stu - Send START_UNIT to device. * @scmd: &scsi_cmnd to send START_UNIT * * Return value: * 0 - Device is ready. 1 - Device NOT ready. */ static int scsi_eh_try_stu(struct scsi_cmnd *scmd) { static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0}; if (scmd->device->allow_restart) { int i, rtn = NEEDS_RETRY; for (i = 0; rtn == NEEDS_RETRY && i < 2; i++) rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0); if (rtn == SUCCESS) return 0; } return 1; } /** * scsi_eh_stu - send START_UNIT if needed * @shost: &scsi host being recovered. * @work_q: &list_head for pending commands. * @done_q: &list_head for processed commands. * * Notes: * If commands are failing due to not ready, initializing command required, * try revalidating the device, which will end up sending a start unit. */ static int scsi_eh_stu(struct Scsi_Host *shost, struct list_head *work_q, struct list_head *done_q) { struct scsi_cmnd *scmd, *stu_scmd, *next; struct scsi_device *sdev; shost_for_each_device(sdev, shost) { stu_scmd = NULL; list_for_each_entry(scmd, work_q, eh_entry) if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) && scsi_check_sense(scmd) == FAILED ) { stu_scmd = scmd; break; } if (!stu_scmd) continue; SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:" " 0x%p\n", current->comm, sdev)); if (!scsi_eh_try_stu(stu_scmd)) { if (!scsi_device_online(sdev) || !scsi_eh_tur(stu_scmd)) { list_for_each_entry_safe(scmd, next, work_q, eh_entry) { if (scmd->device == sdev) scsi_eh_finish_cmd(scmd, done_q); } } } else { SCSI_LOG_ERROR_RECOVERY(3, printk("%s: START_UNIT failed to sdev:" " 0x%p\n", current->comm, sdev)); } } return list_empty(work_q); } /** * scsi_eh_bus_device_reset - send bdr if needed * @shost: scsi host being recovered. * @work_q: &list_head for pending commands. * @done_q: &list_head for processed commands. * * Notes: * Try a bus device reset. Still, look to see whether we have multiple * devices that are jammed or not - if we have multiple devices, it * makes no sense to try bus_device_reset - we really would need to try * a bus_reset instead. */ static int scsi_eh_bus_device_reset(struct Scsi_Host *shost, struct list_head *work_q, struct list_head *done_q) { struct scsi_cmnd *scmd, *bdr_scmd, *next; struct scsi_device *sdev; int rtn; shost_for_each_device(sdev, shost) { bdr_scmd = NULL; list_for_each_entry(scmd, work_q, eh_entry) if (scmd->device == sdev) { bdr_scmd = scmd; break; } if (!bdr_scmd) continue; SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:" " 0x%p\n", current->comm, sdev)); rtn = scsi_try_bus_device_reset(bdr_scmd); if (rtn == SUCCESS || rtn == FAST_IO_FAIL) { if (!scsi_device_online(sdev) || rtn == FAST_IO_FAIL || !scsi_eh_tur(bdr_scmd)) { list_for_each_entry_safe(scmd, next, work_q, eh_entry) { if (scmd->device == sdev) scsi_eh_finish_cmd(scmd, done_q); } } } else { SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR" " failed sdev:" "0x%p\n", current->comm, sdev)); } } return list_empty(work_q); } /** * scsi_eh_target_reset - send target reset if needed * @shost: scsi host being recovered. * @work_q: &list_head for pending commands. * @done_q: &list_head for processed commands. * * Notes: * Try a target reset. */ static int scsi_eh_target_reset(struct Scsi_Host *shost, struct list_head *work_q, struct list_head *done_q) { LIST_HEAD(tmp_list); LIST_HEAD(check_list); list_splice_init(work_q, &tmp_list); while (!list_empty(&tmp_list)) { struct scsi_cmnd *next, *scmd; int rtn; unsigned int id; scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry); id = scmd_id(scmd); SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset " "to target %d\n", current->comm, id)); rtn = scsi_try_target_reset(scmd); if (rtn != SUCCESS && rtn != FAST_IO_FAIL) SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset" " failed target: " "%d\n", current->comm, id)); list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) { if (scmd_id(scmd) != id) continue; if (rtn == SUCCESS) list_move_tail(&scmd->eh_entry, &check_list); else if (rtn == FAST_IO_FAIL) scsi_eh_finish_cmd(scmd, done_q); else /* push back on work queue for further processing */ list_move(&scmd->eh_entry, work_q); } } return scsi_eh_test_devices(&check_list, work_q, done_q, 0); } /** * scsi_eh_bus_reset - send a bus reset * @shost: &scsi host being recovered. * @work_q: &list_head for pending commands. * @done_q: &list_head for processed commands. */ static int scsi_eh_bus_reset(struct Scsi_Host *shost, struct list_head *work_q, struct list_head *done_q) { struct scsi_cmnd *scmd, *chan_scmd, *next; LIST_HEAD(check_list); unsigned int channel; int rtn; /* * we really want to loop over the various channels, and do this on * a channel by channel basis. we should also check to see if any * of the failed commands are on soft_reset devices, and if so, skip * the reset. */ for (channel = 0; channel <= shost->max_channel; channel++) { chan_scmd = NULL; list_for_each_entry(scmd, work_q, eh_entry) { if (channel == scmd_channel(scmd)) { chan_scmd = scmd; break; /* * FIXME add back in some support for * soft_reset devices. */ } } if (!chan_scmd) continue; SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:" " %d\n", current->comm, channel)); rtn = scsi_try_bus_reset(chan_scmd); if (rtn == SUCCESS || rtn == FAST_IO_FAIL) { list_for_each_entry_safe(scmd, next, work_q, eh_entry) { if (channel == scmd_channel(scmd)) { if (rtn == FAST_IO_FAIL) scsi_eh_finish_cmd(scmd, done_q); else list_move_tail(&scmd->eh_entry, &check_list); } } } else { SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST" " failed chan: %d\n", current->comm, channel)); } } return scsi_eh_test_devices(&check_list, work_q, done_q, 0); } /** * scsi_eh_host_reset - send a host reset * @work_q: list_head for processed commands. * @done_q: list_head for processed commands. */ static int scsi_eh_host_reset(struct list_head *work_q, struct list_head *done_q) { struct scsi_cmnd *scmd, *next; LIST_HEAD(check_list); int rtn; if (!list_empty(work_q)) { scmd = list_entry(work_q->next, struct scsi_cmnd, eh_entry); SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n" , current->comm)); rtn = scsi_try_host_reset(scmd); if (rtn == SUCCESS) { list_splice_init(work_q, &check_list); } else if (rtn == FAST_IO_FAIL) { list_for_each_entry_safe(scmd, next, work_q, eh_entry) { scsi_eh_finish_cmd(scmd, done_q); } } else { SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST" " failed\n", current->comm)); } } return scsi_eh_test_devices(&check_list, work_q, done_q, 1); } /** * scsi_eh_offline_sdevs - offline scsi devices that fail to recover * @work_q: list_head for processed commands. * @done_q: list_head for processed commands. */ static void scsi_eh_offline_sdevs(struct list_head *work_q, struct list_head *done_q) { struct scsi_cmnd *scmd, *next; list_for_each_entry_safe(scmd, next, work_q, eh_entry) { sdev_printk(KERN_INFO, scmd->device, "Device offlined - " "not ready after error recovery\n"); scsi_device_set_state(scmd->device, SDEV_OFFLINE); if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) { /* * FIXME: Handle lost cmds. */ } scsi_eh_finish_cmd(scmd, done_q); } return; } /** * scsi_noretry_cmd - determinte if command should be failed fast * @scmd: SCSI cmd to examine. */ int scsi_noretry_cmd(struct scsi_cmnd *scmd) { switch (host_byte(scmd->result)) { case DID_OK: break; case DID_BUS_BUSY: return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT); case DID_PARITY: return (scmd->request->cmd_flags & REQ_FAILFAST_DEV); case DID_ERROR: if (msg_byte(scmd->result) == COMMAND_COMPLETE && status_byte(scmd->result) == RESERVATION_CONFLICT) return 0; /* fall through */ case DID_SOFT_ERROR: 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; } return 0; } /** * scsi_decide_disposition - Disposition a cmd on return from LLD. * @scmd: SCSI cmd to examine. * * Notes: * This is *only* called when we are examining the status after sending * out the actual data command. any commands that are queued for error * recovery (e.g. test_unit_ready) do *not* come through here. * * When this routine returns failed, it means the error handler thread * is woken. In cases where the error code indicates an error that * doesn't require the error handler read (i.e. we don't need to * abort/reset), this function should return SUCCESS. */ int scsi_decide_disposition(struct scsi_cmnd *scmd) { int rtn; /* * if the device is offline, then we clearly just pass the result back * up to the top level. */ if (!scsi_device_online(scmd->device)) { SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report" " as SUCCESS\n", __func__)); return SUCCESS; } /* * first check the host byte, to see if there is anything in there * that would indicate what we need to do. */ switch (host_byte(scmd->result)) { case DID_PASSTHROUGH: /* * no matter what, pass this through to the upper layer. * nuke this special code so that it looks like we are saying * did_ok. */ scmd->result &= 0xff00ffff; return SUCCESS; case DID_OK: /* * looks good. drop through, and check the next byte. */ break; 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 * that it indicates SUCCESS. */ return SUCCESS; /* * when the low level driver returns did_soft_error, * it is responsible for keeping an internal retry counter * in order to avoid endless loops (db) * * actually this is a bug in this function here. we should * be mindful of the maximum number of retries specified * and not get stuck in a loop. */ case DID_SOFT_ERROR: goto maybe_retry; case DID_IMM_RETRY: return NEEDS_RETRY; case DID_REQUEUE: return ADD_TO_MLQUEUE; case DID_TRANSPORT_DISRUPTED: /* * LLD/transport was disrupted during processing of the IO. * The transport class is now blocked/blocking, * and the transport will decide what to do with the IO * based on its timers and recovery capablilities if * there are enough retries. */ goto maybe_retry; case DID_TRANSPORT_FAILFAST: /* * The transport decided to failfast the IO (most likely * the fast io fail tmo fired), so send IO directly upwards. */ return SUCCESS; case DID_ERROR: if (msg_byte(scmd->result) == COMMAND_COMPLETE && status_byte(scmd->result) == RESERVATION_CONFLICT) /* * execute reservation conflict processing code * lower down */ break; /* fallthrough */ case DID_BUS_BUSY: case DID_PARITY: goto maybe_retry; case DID_TIME_OUT: /* * when we scan the bus, we get timeout messages for * these commands if there is no device available. * other hosts report did_no_connect for the same thing. */ if ((scmd->cmnd[0] == TEST_UNIT_READY || scmd->cmnd[0] == INQUIRY)) { return SUCCESS; } else { return FAILED; } case DID_RESET: return SUCCESS; default: return FAILED; } /* * next, check the message byte. */ if (msg_byte(scmd->result) != COMMAND_COMPLETE) return FAILED; /* * check the status byte to see if this indicates anything special. */ switch (status_byte(scmd->result)) { case QUEUE_FULL: scsi_handle_queue_full(scmd->device); /* * the case of trying to send too many commands to a * tagged queueing device. */ case BUSY: /* * device can't talk to us at the moment. Should only * occur (SAM-3) when the task queue is empty, so will cause * the empty queue handling to trigger a stall in the * device. */ return ADD_TO_MLQUEUE; case GOOD: scsi_handle_queue_ramp_up(scmd->device); case COMMAND_TERMINATED: return SUCCESS; case TASK_ABORTED: goto maybe_retry; case CHECK_CONDITION: rtn = scsi_check_sense(scmd); if (rtn == NEEDS_RETRY) goto maybe_retry; else if (rtn == TARGET_ERROR) { /* * Need to modify host byte to signal a * permanent target failure */ scmd->result |= (DID_TARGET_FAILURE << 16); rtn = SUCCESS; } /* if rtn == FAILED, we have no sense information; * returning FAILED will wake the error handler thread * to collect the sense and redo the decide * disposition */ return rtn; case CONDITION_GOOD: case INTERMEDIATE_GOOD: case INTERMEDIATE_C_GOOD: case ACA_ACTIVE: /* * who knows? FIXME(eric) */ return SUCCESS; case RESERVATION_CONFLICT: sdev_printk(KERN_INFO, scmd->device, "reservation conflict\n"); scmd->result |= (DID_NEXUS_FAILURE << 16); return SUCCESS; /* causes immediate i/o error */ default: return FAILED; } return FAILED; maybe_retry: /* we requeue for retry because the error was retryable, and * the request was not marked fast fail. Note that above, * even if the request is marked fast fail, we still requeue * for queue congestion conditions (QUEUE_FULL or BUSY) */ if ((++scmd->retries) <= scmd->allowed && !scsi_noretry_cmd(scmd)) { return NEEDS_RETRY; } else { /* * no more retries - report this one back to upper level. */ return SUCCESS; } } static void eh_lock_door_done(struct request *req, int uptodate) { __blk_put_request(req->q, req); } /** * scsi_eh_lock_door - Prevent medium removal for the specified device * @sdev: SCSI device to prevent medium removal * * Locking: * We must be called from process context. * * Notes: * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the * head of the devices request queue, and continue. */ static void scsi_eh_lock_door(struct scsi_device *sdev) { struct request *req; /* * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a * request becomes available */ req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL); req->cmd[0] = ALLOW_MEDIUM_REMOVAL; req->cmd[1] = 0; req->cmd[2] = 0; req->cmd[3] = 0; req->cmd[4] = SCSI_REMOVAL_PREVENT; req->cmd[5] = 0; req->cmd_len = COMMAND_SIZE(req->cmd[0]); req->cmd_type = REQ_TYPE_BLOCK_PC; req->cmd_flags |= REQ_QUIET; req->timeout = 10 * HZ; req->retries = 5; blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done); } /** * scsi_restart_operations - restart io operations to the specified host. * @shost: Host we are restarting. * * Notes: * When we entered the error handler, we blocked all further i/o to * this device. we need to 'reverse' this process. */ static void scsi_restart_operations(struct Scsi_Host *shost) { struct scsi_device *sdev; unsigned long flags; /* * If the door was locked, we need to insert a door lock request * onto the head of the SCSI request queue for the device. There * is no point trying to lock the door of an off-line device. */ shost_for_each_device(sdev, shost) { if (scsi_device_online(sdev) && sdev->locked) scsi_eh_lock_door(sdev); } /* * next free up anything directly waiting upon the host. this * will be requests for character device operations, and also for * ioctls to queued block devices. */ SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n", __func__)); spin_lock_irqsave(shost->host_lock, flags); if (scsi_host_set_state(shost, SHOST_RUNNING)) if (scsi_host_set_state(shost, SHOST_CANCEL)) BUG_ON(scsi_host_set_state(shost, SHOST_DEL)); spin_unlock_irqrestore(shost->host_lock, flags); wake_up(&shost->host_wait); /* * finally we need to re-initiate requests that may be pending. we will * have had everything blocked while error handling is taking place, and * now that error recovery is done, we will need to ensure that these * requests are started. */ scsi_run_host_queues(shost); } /** * scsi_eh_ready_devs - check device ready state and recover if not. * @shost: host to be recovered. * @work_q: &list_head for pending commands. * @done_q: &list_head for processed commands. */ void scsi_eh_ready_devs(struct Scsi_Host *shost, struct list_head *work_q, struct list_head *done_q) { if (!scsi_eh_stu(shost, work_q, done_q)) if (!scsi_eh_bus_device_reset(shost, work_q, done_q)) if (!scsi_eh_target_reset(shost, work_q, done_q)) if (!scsi_eh_bus_reset(shost, work_q, done_q)) if (!scsi_eh_host_reset(work_q, done_q)) scsi_eh_offline_sdevs(work_q, done_q); } EXPORT_SYMBOL_GPL(scsi_eh_ready_devs); /** * scsi_eh_flush_done_q - finish processed commands or retry them. * @done_q: list_head of processed commands. */ void scsi_eh_flush_done_q(struct list_head *done_q) { struct scsi_cmnd *scmd, *next; list_for_each_entry_safe(scmd, next, done_q, eh_entry) { list_del_init(&scmd->eh_entry); if (scsi_device_online(scmd->device) && !scsi_noretry_cmd(scmd) && (++scmd->retries <= scmd->allowed)) { SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush" " retry cmd: %p\n", current->comm, scmd)); scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY); } else { /* * If just we got sense for the device (called * scsi_eh_get_sense), scmd->result is already * set, do not set DRIVER_TIMEOUT. */ if (!scmd->result) scmd->result |= (DRIVER_TIMEOUT << 24); SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish" " cmd: %p\n", current->comm, scmd)); scsi_finish_command(scmd); } } } EXPORT_SYMBOL(scsi_eh_flush_done_q); /** * scsi_unjam_host - Attempt to fix a host which has a cmd that failed. * @shost: Host to unjam. * * Notes: * When we come in here, we *know* that all commands on the bus have * either completed, failed or timed out. we also know that no further * commands are being sent to the host, so things are relatively quiet * and we have freedom to fiddle with things as we wish. * * This is only the *default* implementation. it is possible for * individual drivers to supply their own version of this function, and * if the maintainer wishes to do this, it is strongly suggested that * this function be taken as a template and modified. this function * was designed to correctly handle problems for about 95% of the * different cases out there, and it should always provide at least a * reasonable amount of error recovery. * * Any command marked 'failed' or 'timeout' must eventually have * scsi_finish_cmd() called for it. we do all of the retry stuff * here, so when we restart the host after we return it should have an * empty queue. */ static void scsi_unjam_host(struct Scsi_Host *shost) { unsigned long flags; LIST_HEAD(eh_work_q); LIST_HEAD(eh_done_q); spin_lock_irqsave(shost->host_lock, flags); list_splice_init(&shost->eh_cmd_q, &eh_work_q); spin_unlock_irqrestore(shost->host_lock, flags); SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q)); if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q)) if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q)) scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q); scsi_eh_flush_done_q(&eh_done_q); } /** * scsi_error_handler - SCSI error handler thread * @data: Host for which we are running. * * Notes: * This is the main error handling loop. This is run as a kernel thread * for every SCSI host and handles all error handling activity. */ int scsi_error_handler(void *data) { struct Scsi_Host *shost = data; /* * We use TASK_INTERRUPTIBLE so that the thread is not * counted against the load average as a running process. * We never actually get interrupted because kthread_run * disables signal delivery for the created thread. */ set_current_state(TASK_INTERRUPTIBLE); while (!kthread_should_stop()) { if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) || shost->host_failed != shost->host_busy) { SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d sleeping\n", shost->host_no)); schedule(); set_current_state(TASK_INTERRUPTIBLE); continue; } __set_current_state(TASK_RUNNING); SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d waking up\n", shost->host_no)); /* * We have a host that is failing for some reason. Figure out * what we need to do to get it up and online again (if we can). * If we fail, we end up taking the thing offline. */ if (scsi_autopm_get_host(shost) != 0) { SCSI_LOG_ERROR_RECOVERY(1, printk(KERN_ERR "Error handler scsi_eh_%d " "unable to autoresume\n", shost->host_no)); continue; } if (shost->transportt->eh_strategy_handler) shost->transportt->eh_strategy_handler(shost); else scsi_unjam_host(shost); /* * Note - if the above fails completely, the action is to take * individual devices offline and flush the queue of any * outstanding requests that may have been pending. When we * restart, we restart any I/O to any other devices on the bus * which are still online. */ scsi_restart_operations(shost); scsi_autopm_put_host(shost); set_current_state(TASK_INTERRUPTIBLE); } __set_current_state(TASK_RUNNING); SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d exiting\n", shost->host_no)); shost->ehandler = NULL; return 0; } /* * Function: scsi_report_bus_reset() * * Purpose: Utility function used by low-level drivers to report that * they have observed a bus reset on the bus being handled. * * Arguments: shost - Host in question * channel - channel on which reset was observed. * * Returns: Nothing * * Lock status: Host lock must be held. * * Notes: This only needs to be called if the reset is one which * originates from an unknown location. Resets originated * by the mid-level itself don't need to call this, but there * should be no harm. * * The main purpose of this is to make sure that a CHECK_CONDITION * is properly treated. */ void scsi_report_bus_reset(struct Scsi_Host *shost, int channel) { struct scsi_device *sdev; __shost_for_each_device(sdev, shost) { if (channel == sdev_channel(sdev)) __scsi_report_device_reset(sdev, NULL); } } EXPORT_SYMBOL(scsi_report_bus_reset); /* * Function: scsi_report_device_reset() * * Purpose: Utility function used by low-level drivers to report that * they have observed a device reset on the device being handled. * * Arguments: shost - Host in question * channel - channel on which reset was observed * target - target on which reset was observed * * Returns: Nothing * * Lock status: Host lock must be held * * Notes: This only needs to be called if the reset is one which * originates from an unknown location. Resets originated * by the mid-level itself don't need to call this, but there * should be no harm. * * The main purpose of this is to make sure that a CHECK_CONDITION * is properly treated. */ void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target) { struct scsi_device *sdev; __shost_for_each_device(sdev, shost) { if (channel == sdev_channel(sdev) && target == sdev_id(sdev)) __scsi_report_device_reset(sdev, NULL); } } EXPORT_SYMBOL(scsi_report_device_reset); static void scsi_reset_provider_done_command(struct scsi_cmnd *scmd) { } /* * Function: scsi_reset_provider * * Purpose: Send requested reset to a bus or device at any phase. * * Arguments: device - device to send reset to * flag - reset type (see scsi.h) * * Returns: SUCCESS/FAILURE. * * Notes: This is used by the SCSI Generic driver to provide * Bus/Device reset capability. */ int scsi_reset_provider(struct scsi_device *dev, int flag) { struct scsi_cmnd *scmd; struct Scsi_Host *shost = dev->host; struct request req; unsigned long flags; int rtn; if (scsi_autopm_get_host(shost) < 0) return FAILED; scmd = scsi_get_command(dev, GFP_KERNEL); blk_rq_init(NULL, &req); scmd->request = &req; scmd->cmnd = req.cmd; scmd->scsi_done = scsi_reset_provider_done_command; memset(&scmd->sdb, 0, sizeof(scmd->sdb)); scmd->cmd_len = 0; scmd->sc_data_direction = DMA_BIDIRECTIONAL; spin_lock_irqsave(shost->host_lock, flags); shost->tmf_in_progress = 1; spin_unlock_irqrestore(shost->host_lock, flags); switch (flag) { case SCSI_TRY_RESET_DEVICE: rtn = scsi_try_bus_device_reset(scmd); if (rtn == SUCCESS) break; /* FALLTHROUGH */ case SCSI_TRY_RESET_TARGET: rtn = scsi_try_target_reset(scmd); if (rtn == SUCCESS) break; /* FALLTHROUGH */ case SCSI_TRY_RESET_BUS: rtn = scsi_try_bus_reset(scmd); if (rtn == SUCCESS) break; /* FALLTHROUGH */ case SCSI_TRY_RESET_HOST: rtn = scsi_try_host_reset(scmd); break; default: rtn = FAILED; } spin_lock_irqsave(shost->host_lock, flags); shost->tmf_in_progress = 0; spin_unlock_irqrestore(shost->host_lock, flags); /* * be sure to wake up anyone who was sleeping or had their queue * suspended while we performed the TMF. */ SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart after TMF\n", __func__)); wake_up(&shost->host_wait); scsi_run_host_queues(shost); scsi_next_command(scmd); scsi_autopm_put_host(shost); return rtn; } EXPORT_SYMBOL(scsi_reset_provider); /** * scsi_normalize_sense - normalize main elements from either fixed or * descriptor sense data format into a common format. * * @sense_buffer: byte array containing sense data returned by device * @sb_len: number of valid bytes in sense_buffer * @sshdr: pointer to instance of structure that common * elements are written to. * * Notes: * The "main elements" from sense data are: response_code, sense_key, * asc, ascq and additional_length (only for descriptor format). * * Typically this function can be called after a device has * responded to a SCSI command with the CHECK_CONDITION status. * * Return value: * 1 if valid sense data information found, else 0; */ int scsi_normalize_sense(const u8 *sense_buffer, int sb_len, struct scsi_sense_hdr *sshdr) { if (!sense_buffer || !sb_len) return 0; memset(sshdr, 0, sizeof(struct scsi_sense_hdr)); sshdr->response_code = (sense_buffer[0] & 0x7f); if (!scsi_sense_valid(sshdr)) return 0; if (sshdr->response_code >= 0x72) { /* * descriptor format */ if (sb_len > 1) sshdr->sense_key = (sense_buffer[1] & 0xf); if (sb_len > 2) sshdr->asc = sense_buffer[2]; if (sb_len > 3) sshdr->ascq = sense_buffer[3]; if (sb_len > 7) sshdr->additional_length = sense_buffer[7]; } else { /* * fixed format */ if (sb_len > 2) sshdr->sense_key = (sense_buffer[2] & 0xf); if (sb_len > 7) { sb_len = (sb_len < (sense_buffer[7] + 8)) ? sb_len : (sense_buffer[7] + 8); if (sb_len > 12) sshdr->asc = sense_buffer[12]; if (sb_len > 13) sshdr->ascq = sense_buffer[13]; } } return 1; } EXPORT_SYMBOL(scsi_normalize_sense); int scsi_command_normalize_sense(struct scsi_cmnd *cmd, struct scsi_sense_hdr *sshdr) { return scsi_normalize_sense(cmd->sense_buffer, SCSI_SENSE_BUFFERSIZE, sshdr); } EXPORT_SYMBOL(scsi_command_normalize_sense); /** * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format. * @sense_buffer: byte array of descriptor format sense data * @sb_len: number of valid bytes in sense_buffer * @desc_type: value of descriptor type to find * (e.g. 0 -> information) * * Notes: * only valid when sense data is in descriptor format * * Return value: * pointer to start of (first) descriptor if found else NULL */ const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len, int desc_type) { int add_sen_len, add_len, desc_len, k; const u8 * descp; if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7]))) return NULL; if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73)) return NULL; add_sen_len = (add_sen_len < (sb_len - 8)) ? add_sen_len : (sb_len - 8); descp = &sense_buffer[8]; for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) { descp += desc_len; add_len = (k < (add_sen_len - 1)) ? descp[1]: -1; desc_len = add_len + 2; if (descp[0] == desc_type) return descp; if (add_len < 0) // short descriptor ?? break; } return NULL; } EXPORT_SYMBOL(scsi_sense_desc_find); /** * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format) * @sense_buffer: byte array of sense data * @sb_len: number of valid bytes in sense_buffer * @info_out: pointer to 64 integer where 8 or 4 byte information * field will be placed if found. * * Return value: * 1 if information field found, 0 if not found. */ int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len, u64 * info_out) { int j; const u8 * ucp; u64 ull; if (sb_len < 7) return 0; switch (sense_buffer[0] & 0x7f) { case 0x70: case 0x71: if (sense_buffer[0] & 0x80) { *info_out = (sense_buffer[3] << 24) + (sense_buffer[4] << 16) + (sense_buffer[5] << 8) + sense_buffer[6]; return 1; } else return 0; case 0x72: case 0x73: ucp = scsi_sense_desc_find(sense_buffer, sb_len, 0 /* info desc */); if (ucp && (0xa == ucp[1])) { ull = 0; for (j = 0; j < 8; ++j) { if (j > 0) ull <<= 8; ull |= ucp[4 + j]; } *info_out = ull; return 1; } else return 0; default: return 0; } } EXPORT_SYMBOL(scsi_get_sense_info_fld); /** * scsi_build_sense_buffer - build sense data in a buffer * @desc: Sense format (non zero == descriptor format, * 0 == fixed format) * @buf: Where to build sense data * @key: Sense key * @asc: Additional sense code * @ascq: Additional sense code qualifier * **/ void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq) { if (desc) { buf[0] = 0x72; /* descriptor, current */ buf[1] = key; buf[2] = asc; buf[3] = ascq; buf[7] = 0; } else { buf[0] = 0x70; /* fixed, current */ buf[2] = key; buf[7] = 0xa; buf[12] = asc; buf[13] = ascq; } } EXPORT_SYMBOL(scsi_build_sense_buffer);