diff options
Diffstat (limited to 'drivers/scsi/scsi_error.c')
| -rw-r--r-- | drivers/scsi/scsi_error.c | 2576 |
1 files changed, 2576 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c new file mode 100644 index 000000000..d983f4a0e --- /dev/null +++ b/drivers/scsi/scsi_error.c @@ -0,0 +1,2576 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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 <linux/module.h> +#include <linux/sched.h> +#include <linux/gfp.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/kernel.h> +#include <linux/freezer.h> +#include <linux/kthread.h> +#include <linux/interrupt.h> +#include <linux/blkdev.h> +#include <linux/delay.h> +#include <linux/jiffies.h> + +#include <scsi/scsi.h> +#include <scsi/scsi_cmnd.h> +#include <scsi/scsi_dbg.h> +#include <scsi/scsi_device.h> +#include <scsi/scsi_driver.h> +#include <scsi/scsi_eh.h> +#include <scsi/scsi_common.h> +#include <scsi/scsi_transport.h> +#include <scsi/scsi_host.h> +#include <scsi/scsi_ioctl.h> +#include <scsi/scsi_dh.h> +#include <scsi/scsi_devinfo.h> +#include <scsi/sg.h> + +#include "scsi_priv.h" +#include "scsi_logging.h" +#include "scsi_transport_api.h" + +#include <trace/events/scsi.h> + +#include <asm/unaligned.h> + +/* + * 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); +static enum scsi_disposition scsi_try_to_abort_cmd(const struct scsi_host_template *, + struct scsi_cmnd *); + +void scsi_eh_wakeup(struct Scsi_Host *shost) +{ + lockdep_assert_held(shost->host_lock); + + if (scsi_host_busy(shost) == shost->host_failed) { + trace_scsi_eh_wakeup(shost); + wake_up_process(shost->ehandler); + SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost, + "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); + +static int scsi_host_eh_past_deadline(struct Scsi_Host *shost) +{ + if (!shost->last_reset || shost->eh_deadline == -1) + return 0; + + /* + * 32bit accesses are guaranteed to be atomic + * (on all supported architectures), so instead + * of using a spinlock we can as well double check + * if eh_deadline has been set to 'off' during the + * time_before call. + */ + if (time_before(jiffies, shost->last_reset + shost->eh_deadline) && + shost->eh_deadline > -1) + return 0; + + return 1; +} + +static bool scsi_cmd_retry_allowed(struct scsi_cmnd *cmd) +{ + if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT) + return true; + + return ++cmd->retries <= cmd->allowed; +} + +static bool scsi_eh_should_retry_cmd(struct scsi_cmnd *cmd) +{ + struct scsi_device *sdev = cmd->device; + struct Scsi_Host *host = sdev->host; + + if (host->hostt->eh_should_retry_cmd) + return host->hostt->eh_should_retry_cmd(cmd); + + return true; +} + +/** + * scmd_eh_abort_handler - Handle command aborts + * @work: command to be aborted. + * + * Note: this function must be called only for a command that has timed out. + * Because the block layer marks a request as complete before it calls + * scsi_timeout(), a .scsi_done() call from the LLD for a command that has + * timed out do not have any effect. Hence it is safe to call + * scsi_finish_command() from this function. + */ +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; + struct Scsi_Host *shost = sdev->host; + enum scsi_disposition rtn; + unsigned long flags; + + if (scsi_host_eh_past_deadline(shost)) { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "eh timeout, not aborting\n")); + goto out; + } + + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "aborting command\n")); + rtn = scsi_try_to_abort_cmd(shost->hostt, scmd); + if (rtn != SUCCESS) { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "cmd abort %s\n", + (rtn == FAST_IO_FAIL) ? + "not send" : "failed")); + goto out; + } + set_host_byte(scmd, DID_TIME_OUT); + if (scsi_host_eh_past_deadline(shost)) { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "eh timeout, not retrying " + "aborted command\n")); + goto out; + } + + spin_lock_irqsave(shost->host_lock, flags); + list_del_init(&scmd->eh_entry); + + /* + * If the abort succeeds, and there is no further + * EH action, clear the ->last_reset time. + */ + if (list_empty(&shost->eh_abort_list) && + list_empty(&shost->eh_cmd_q)) + if (shost->eh_deadline != -1) + shost->last_reset = 0; + + spin_unlock_irqrestore(shost->host_lock, flags); + + if (!scsi_noretry_cmd(scmd) && + scsi_cmd_retry_allowed(scmd) && + scsi_eh_should_retry_cmd(scmd)) { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_WARNING, scmd, + "retry aborted command\n")); + scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY); + } else { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_WARNING, scmd, + "finish aborted command\n")); + scsi_finish_command(scmd); + } + return; + +out: + spin_lock_irqsave(shost->host_lock, flags); + list_del_init(&scmd->eh_entry); + spin_unlock_irqrestore(shost->host_lock, flags); + + scsi_eh_scmd_add(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 (!shost->hostt->eh_abort_handler) { + /* No abort handler, fail command directly */ + return FAILED; + } + + 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, + "previous abort failed\n")); + BUG_ON(delayed_work_pending(&scmd->abort_work)); + return FAILED; + } + + spin_lock_irqsave(shost->host_lock, flags); + if (shost->eh_deadline != -1 && !shost->last_reset) + shost->last_reset = jiffies; + BUG_ON(!list_empty(&scmd->eh_entry)); + list_add_tail(&scmd->eh_entry, &shost->eh_abort_list); + spin_unlock_irqrestore(shost->host_lock, flags); + + scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED; + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, "abort scheduled\n")); + queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100); + return SUCCESS; +} + +/** + * scsi_eh_reset - call into ->eh_action to reset internal counters + * @scmd: scmd to run eh on. + * + * The scsi driver might be carrying internal state about the + * devices, so we need to call into the driver to reset the + * internal state once the error handler is started. + */ +static void scsi_eh_reset(struct scsi_cmnd *scmd) +{ + if (!blk_rq_is_passthrough(scsi_cmd_to_rq(scmd))) { + struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd); + if (sdrv->eh_reset) + sdrv->eh_reset(scmd); + } +} + +static void scsi_eh_inc_host_failed(struct rcu_head *head) +{ + struct scsi_cmnd *scmd = container_of(head, typeof(*scmd), rcu); + struct Scsi_Host *shost = scmd->device->host; + unsigned long flags; + + spin_lock_irqsave(shost->host_lock, flags); + shost->host_failed++; + scsi_eh_wakeup(shost); + spin_unlock_irqrestore(shost->host_lock, flags); +} + +/** + * scsi_eh_scmd_add - add scsi cmd to error handling. + * @scmd: scmd to run eh on. + */ +void scsi_eh_scmd_add(struct scsi_cmnd *scmd) +{ + struct Scsi_Host *shost = scmd->device->host; + unsigned long flags; + int ret; + + WARN_ON_ONCE(!shost->ehandler); + + spin_lock_irqsave(shost->host_lock, flags); + if (scsi_host_set_state(shost, SHOST_RECOVERY)) { + ret = scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY); + WARN_ON_ONCE(ret); + } + if (shost->eh_deadline != -1 && !shost->last_reset) + shost->last_reset = jiffies; + + scsi_eh_reset(scmd); + list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q); + spin_unlock_irqrestore(shost->host_lock, flags); + /* + * Ensure that all tasks observe the host state change before the + * host_failed change. + */ + call_rcu_hurry(&scmd->rcu, scsi_eh_inc_host_failed); +} + +/** + * scsi_timeout - 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_timeout(struct request *req) +{ + struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req); + struct Scsi_Host *host = scmd->device->host; + + trace_scsi_dispatch_cmd_timeout(scmd); + scsi_log_completion(scmd, TIMEOUT_ERROR); + + atomic_inc(&scmd->device->iotmo_cnt); + if (host->eh_deadline != -1 && !host->last_reset) + host->last_reset = jiffies; + + if (host->hostt->eh_timed_out) { + switch (host->hostt->eh_timed_out(scmd)) { + case SCSI_EH_DONE: + return BLK_EH_DONE; + case SCSI_EH_RESET_TIMER: + return BLK_EH_RESET_TIMER; + case SCSI_EH_NOT_HANDLED: + break; + } + } + + /* + * If scsi_done() has already set SCMD_STATE_COMPLETE, do not modify + * *scmd. + */ + if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state)) + return BLK_EH_DONE; + atomic_inc(&scmd->device->iodone_cnt); + if (scsi_abort_command(scmd) != SUCCESS) { + set_host_byte(scmd, DID_TIME_OUT); + scsi_eh_scmd_add(scmd); + } + + return BLK_EH_DONE; +} + +/** + * 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); + + 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_ABORT_SCHEDULED) + ++cmd_cancel; + else + ++cmd_failed; + } + } + + if (cmd_cancel || cmd_failed) { + SCSI_LOG_ERROR_RECOVERY(3, + shost_printk(KERN_INFO, shost, + "%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, shost_printk(KERN_INFO, shost, + "Total of %d commands on %d" + " devices require eh work\n", + total_failures, devices_failed)); +} +#endif + + /** + * scsi_report_lun_change - Set flag on all *other* devices on the same target + * to indicate that a UNIT ATTENTION is expected. + * @sdev: Device reporting the UNIT ATTENTION + */ +static void scsi_report_lun_change(struct scsi_device *sdev) +{ + sdev->sdev_target->expecting_lun_change = 1; +} + +/** + * scsi_report_sense - Examine scsi sense information and log messages for + * certain conditions, also issue uevents for some of them. + * @sdev: Device reporting the sense code + * @sshdr: sshdr to be examined + */ +static void scsi_report_sense(struct scsi_device *sdev, + struct scsi_sense_hdr *sshdr) +{ + enum scsi_device_event evt_type = SDEV_EVT_MAXBITS; /* i.e. none */ + + if (sshdr->sense_key == UNIT_ATTENTION) { + if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) { + evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED; + sdev_printk(KERN_WARNING, sdev, + "Inquiry data has changed"); + } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) { + evt_type = SDEV_EVT_LUN_CHANGE_REPORTED; + scsi_report_lun_change(sdev); + sdev_printk(KERN_WARNING, sdev, + "LUN assignments on this target have " + "changed. The Linux SCSI layer does not " + "automatically remap LUN assignments.\n"); + } else if (sshdr->asc == 0x3f) + sdev_printk(KERN_WARNING, sdev, + "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) { + evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED; + sdev_printk(KERN_WARNING, sdev, + "Warning! Received an indication that the " + "LUN reached a thin provisioning soft " + "threshold.\n"); + } + + if (sshdr->asc == 0x29) { + evt_type = SDEV_EVT_POWER_ON_RESET_OCCURRED; + /* + * Do not print message if it is an expected side-effect + * of runtime PM. + */ + if (!sdev->silence_suspend) + sdev_printk(KERN_WARNING, sdev, + "Power-on or device reset occurred\n"); + } + + if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) { + evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED; + sdev_printk(KERN_WARNING, sdev, + "Mode parameters changed"); + } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x06) { + evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED; + sdev_printk(KERN_WARNING, sdev, + "Asymmetric access state changed"); + } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) { + evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED; + sdev_printk(KERN_WARNING, sdev, + "Capacity data has changed"); + } else if (sshdr->asc == 0x2a) + sdev_printk(KERN_WARNING, sdev, + "Parameters changed"); + } + + if (evt_type != SDEV_EVT_MAXBITS) { + set_bit(evt_type, sdev->pending_events); + schedule_work(&sdev->event_work); + } +} + +static inline void set_scsi_ml_byte(struct scsi_cmnd *cmd, u8 status) +{ + cmd->result = (cmd->result & 0xffff00ff) | (status << 8); +} + +/** + * scsi_check_sense - Examine scsi cmd sense + * @scmd: Cmd to have sense checked. + * + * Return value: + * SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE + * + * Notes: + * When a deferred error is detected the current command has + * not been executed and needs retrying. + */ +enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd) +{ + struct request *req = scsi_cmd_to_rq(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 */ + + scsi_report_sense(sdev, &sshdr); + + if (scsi_sense_is_deferred(&sshdr)) + return NEEDS_RETRY; + + if (sdev->handler && sdev->handler->check_sense) { + enum scsi_disposition rc; + + rc = sdev->handler->check_sense(sdev, &sshdr); + if (rc != SCSI_RETURN_NOT_HANDLED) + return rc; + /* handler does not care. Drop down to default handling */ + } + + if (scmd->cmnd[0] == TEST_UNIT_READY && + scmd->submitter != SUBMITTED_BY_SCSI_ERROR_HANDLER) + /* + * nasty: for mid-layer issued TURs, we need to return the + * actual sense data without any recovery attempt. For eh + * issued ones, we need to try to recover and interpret + */ + return SUCCESS; + + /* + * 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; + + /* + * Check aborts due to command duration limit policy: + * ABORTED COMMAND additional sense code with the + * COMMAND TIMEOUT BEFORE PROCESSING or + * COMMAND TIMEOUT DURING PROCESSING or + * COMMAND TIMEOUT DURING PROCESSING DUE TO ERROR RECOVERY + * additional sense code qualifiers. + */ + if (sshdr.asc == 0x2e && + sshdr.ascq >= 0x01 && sshdr.ascq <= 0x03) { + set_scsi_ml_byte(scmd, SCSIML_STAT_DL_TIMEOUT); + req->cmd_flags |= REQ_FAILFAST_DEV; + req->rq_flags |= RQF_QUIET; + return SUCCESS; + } + + if (sshdr.asc == 0x44 && sdev->sdev_bflags & BLIST_RETRY_ITF) + return ADD_TO_MLQUEUE; + if (sshdr.asc == 0xc1 && sshdr.ascq == 0x01 && + sdev->sdev_bflags & BLIST_RETRY_ASC_C1) + return ADD_TO_MLQUEUE; + + 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; + } + } + /* + * we might also expect a cc/ua if another LUN on the target + * reported a UA with an ASC/ASCQ of 3F 0E - + * REPORTED LUNS DATA HAS CHANGED. + */ + if (scmd->device->sdev_target->expecting_lun_change && + sshdr.asc == 0x3f && sshdr.ascq == 0x0e) + 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; + /* + * Pass the UA upwards for a determination in the completion + * functions. + */ + return SUCCESS; + + /* these are not supported */ + case DATA_PROTECT: + if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) { + /* Thin provisioning hard threshold reached */ + set_scsi_ml_byte(scmd, SCSIML_STAT_NOSPC); + return SUCCESS; + } + fallthrough; + case COPY_ABORTED: + case VOLUME_OVERFLOW: + case MISCOMPARE: + case BLANK_CHECK: + set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_FAILURE); + return SUCCESS; + + case MEDIUM_ERROR: + if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */ + sshdr.asc == 0x13 || /* AMNF DATA FIELD */ + sshdr.asc == 0x14) { /* RECORD NOT FOUND */ + set_scsi_ml_byte(scmd, SCSIML_STAT_MED_ERROR); + return SUCCESS; + } + return NEEDS_RETRY; + + case HARDWARE_ERROR: + if (scmd->device->retry_hwerror) + return ADD_TO_MLQUEUE; + else + set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_FAILURE); + fallthrough; + + case ILLEGAL_REQUEST: + if (sshdr.asc == 0x20 || /* Invalid command operation code */ + sshdr.asc == 0x21 || /* Logical block address out of range */ + sshdr.asc == 0x22 || /* Invalid function */ + sshdr.asc == 0x24 || /* Invalid field in cdb */ + sshdr.asc == 0x26 || /* Parameter value invalid */ + sshdr.asc == 0x27) { /* Write protected */ + set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_FAILURE); + } + return SUCCESS; + + case COMPLETED: + if (sshdr.asc == 0x55 && sshdr.ascq == 0x0a) { + set_scsi_ml_byte(scmd, SCSIML_STAT_DL_TIMEOUT); + req->cmd_flags |= REQ_FAILFAST_DEV; + req->rq_flags |= RQF_QUIET; + } + return SUCCESS; + + default: + return SUCCESS; + } +} +EXPORT_SYMBOL_GPL(scsi_check_sense); + +static void scsi_handle_queue_ramp_up(struct scsi_device *sdev) +{ + const struct scsi_host_template *sht = sdev->host->hostt; + struct scsi_device *tmp_sdev; + + if (!sht->track_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; + + scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1); + sdev->last_queue_ramp_up = jiffies; + } +} + +static void scsi_handle_queue_full(struct scsi_device *sdev) +{ + const struct scsi_host_template *sht = sdev->host->hostt; + struct scsi_device *tmp_sdev; + + if (!sht->track_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. + */ + scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1); + } +} + +/** + * 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 enum scsi_disposition 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; + + /* + * now, check the status byte to see if this indicates + * anything special. + */ + switch (get_status_byte(scmd)) { + case SAM_STAT_GOOD: + scsi_handle_queue_ramp_up(scmd->device); + if (scmd->sense_buffer && SCSI_SENSE_VALID(scmd)) + /* + * If we have sense data, call scsi_check_sense() in + * order to set the correct SCSI ML byte (if any). + * No point in checking the return value, since the + * command has already completed successfully. + */ + scsi_check_sense(scmd); + fallthrough; + case SAM_STAT_COMMAND_TERMINATED: + return SUCCESS; + case SAM_STAT_CHECK_CONDITION: + return scsi_check_sense(scmd); + case SAM_STAT_CONDITION_MET: + case SAM_STAT_INTERMEDIATE: + case SAM_STAT_INTERMEDIATE_CONDITION_MET: + /* + * who knows? FIXME(eric) + */ + return SUCCESS; + case SAM_STAT_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 SAM_STAT_TASK_SET_FULL: + scsi_handle_queue_full(scmd->device); + fallthrough; + case SAM_STAT_BUSY: + return NEEDS_RETRY; + default: + return FAILED; + } + return FAILED; +} + +/** + * scsi_eh_done - Completion function for error handling. + * @scmd: Cmd that is done. + */ +void scsi_eh_done(struct scsi_cmnd *scmd) +{ + struct completion *eh_action; + + SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd, + "%s result: %x\n", __func__, 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 host reset. + */ +static enum scsi_disposition scsi_try_host_reset(struct scsi_cmnd *scmd) +{ + unsigned long flags; + enum scsi_disposition rtn; + struct Scsi_Host *host = scmd->device->host; + const struct scsi_host_template *hostt = host->hostt; + + SCSI_LOG_ERROR_RECOVERY(3, + shost_printk(KERN_INFO, host, "Snd Host RST\n")); + + 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 enum scsi_disposition scsi_try_bus_reset(struct scsi_cmnd *scmd) +{ + unsigned long flags; + enum scsi_disposition rtn; + struct Scsi_Host *host = scmd->device->host; + const struct scsi_host_template *hostt = host->hostt; + + SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd, + "%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 enum scsi_disposition scsi_try_target_reset(struct scsi_cmnd *scmd) +{ + unsigned long flags; + enum scsi_disposition rtn; + struct Scsi_Host *host = scmd->device->host; + const 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 enum scsi_disposition scsi_try_bus_device_reset(struct scsi_cmnd *scmd) +{ + enum scsi_disposition rtn; + const 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; +} + +/** + * scsi_try_to_abort_cmd - Ask host to abort a SCSI command + * @hostt: SCSI driver host template + * @scmd: SCSI cmd used to send a target reset + * + * Return value: + * SUCCESS, FAILED, or FAST_IO_FAIL + * + * Notes: + * SUCCESS does not necessarily indicate that the command + * has been aborted; it only indicates that the LLDDs + * has cleared all references to that command. + * LLDDs should return FAILED only if an abort was required + * but could not be executed. LLDDs should return FAST_IO_FAIL + * if the device is temporarily unavailable (eg due to a + * link down on FibreChannel) + */ +static enum scsi_disposition +scsi_try_to_abort_cmd(const 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 recovery + * @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 <= MAX_COMMAND_SIZE) + * @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->data_direction = scmd->sc_data_direction; + ses->sdb = scmd->sdb; + ses->result = scmd->result; + ses->resid_len = scmd->resid_len; + ses->underflow = scmd->underflow; + ses->prot_op = scmd->prot_op; + ses->eh_eflags = scmd->eh_eflags; + + scmd->prot_op = SCSI_PROT_NORMAL; + scmd->eh_eflags = 0; + memcpy(ses->cmnd, scmd->cmnd, sizeof(ses->cmnd)); + memset(scmd->cmnd, 0, sizeof(scmd->cmnd)); + memset(&scmd->sdb, 0, sizeof(scmd->sdb)); + scmd->result = 0; + scmd->resid_len = 0; + + 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 = scmd->sdb.table.orig_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 > sizeof(scmd->cmnd)); + 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 recovery + * @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; + memcpy(scmd->cmnd, ses->cmnd, sizeof(ses->cmnd)); + scmd->sc_data_direction = ses->data_direction; + scmd->sdb = ses->sdb; + scmd->result = ses->result; + scmd->resid_len = ses->resid_len; + scmd->underflow = ses->underflow; + scmd->prot_op = ses->prot_op; + scmd->eh_eflags = ses->eh_eflags; +} +EXPORT_SYMBOL(scsi_eh_restore_cmnd); + +/** + * scsi_send_eh_cmnd - submit a scsi command as part of error recovery + * @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 enum scsi_disposition 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 = timeout, delay; + struct scsi_eh_save ses; + const unsigned long stall_for = msecs_to_jiffies(100); + int rtn; + +retry: + scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes); + shost->eh_action = &done; + + scsi_log_send(scmd); + scmd->submitter = SUBMITTED_BY_SCSI_ERROR_HANDLER; + scmd->flags |= SCMD_LAST; + + /* + * Lock sdev->state_mutex to avoid that scsi_device_quiesce() can + * change the SCSI device state after we have examined it and before + * .queuecommand() is called. + */ + mutex_lock(&sdev->state_mutex); + while (sdev->sdev_state == SDEV_BLOCK && timeleft > 0) { + mutex_unlock(&sdev->state_mutex); + SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev, + "%s: state %d <> %d\n", __func__, sdev->sdev_state, + SDEV_BLOCK)); + delay = min(timeleft, stall_for); + timeleft -= delay; + msleep(jiffies_to_msecs(delay)); + mutex_lock(&sdev->state_mutex); + } + if (sdev->sdev_state != SDEV_BLOCK) + rtn = shost->hostt->queuecommand(shost, scmd); + else + rtn = FAILED; + mutex_unlock(&sdev->state_mutex); + + if (rtn) { + if (timeleft > stall_for) { + scsi_eh_restore_cmnd(scmd, &ses); + + timeleft -= stall_for; + msleep(jiffies_to_msecs(stall_for)); + goto retry; + } + /* signal not to enter either branch of the if () below */ + timeleft = 0; + rtn = FAILED; + } else { + timeleft = wait_for_completion_timeout(&done, timeout); + rtn = SUCCESS; + } + + shost->eh_action = NULL; + + scsi_log_completion(scmd, rtn); + + SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd, + "%s timeleft: %ld\n", + __func__, 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 if we have a zero return and no time left, + * the command must still be pending, so abort it and return FAILED. + * If we never actually managed to issue the command, because + * ->queuecommand() kept returning non zero, use the rtn = FAILED + * value above (so don't execute either branch of the if) + */ + if (timeleft) { + rtn = scsi_eh_completed_normally(scmd); + SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd, + "%s: scsi_eh_completed_normally %x\n", __func__, rtn)); + + switch (rtn) { + case SUCCESS: + case NEEDS_RETRY: + case FAILED: + break; + case ADD_TO_MLQUEUE: + rtn = NEEDS_RETRY; + break; + default: + rtn = FAILED; + break; + } + } else if (rtn != FAILED) { + 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 enum scsi_disposition scsi_request_sense(struct scsi_cmnd *scmd) +{ + return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0); +} + +static enum scsi_disposition +scsi_eh_action(struct scsi_cmnd *scmd, enum scsi_disposition rtn) +{ + if (!blk_rq_is_passthrough(scsi_cmd_to_rq(scmd))) { + struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd); + if (sdrv->eh_action) + rtn = sdrv->eh_action(scmd, rtn); + } + return rtn; +} + +/** + * 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) +{ + 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; + struct Scsi_Host *shost; + enum scsi_disposition rtn; + + /* + * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO, + * should not get sense. + */ + list_for_each_entry_safe(scmd, next, work_q, eh_entry) { + if ((scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) || + SCSI_SENSE_VALID(scmd)) + continue; + + shost = scmd->device->host; + if (scsi_host_eh_past_deadline(shost)) { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "%s: skip request sense, past eh deadline\n", + current->comm)); + break; + } + if (!scsi_status_is_check_condition(scmd->result)) + /* + * don't request sense if there's no check condition + * status because the error we're processing isn't one + * that has a sense code (and some devices get + * confused by sense requests out of the blue) + */ + 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, scmd_printk(KERN_INFO, scmd, + "sense requested, result %x\n", scmd->result)); + SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(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. If the user + * has requested infinite retries, we also want to + * finish this command, so force completion by setting + * retries and allowed to the same value. + */ + if (scmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT) + scmd->retries = scmd->allowed = 1; + else + 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; + enum scsi_disposition rtn; + +retry_tur: + rtn = scsi_send_eh_cmnd(scmd, tur_command, 6, + scmd->device->eh_timeout, 0); + + SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd, + "%s return: %x\n", __func__, rtn)); + + switch (rtn) { + case NEEDS_RETRY: + if (retry_cnt--) + goto retry_tur; + fallthrough; + 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; + + if (!try_stu) { + if (scsi_host_eh_past_deadline(sdev->host)) { + /* Push items back onto work_q */ + list_splice_init(cmd_list, work_q); + SCSI_LOG_ERROR_RECOVERY(3, + sdev_printk(KERN_INFO, sdev, + "%s: skip test device, past eh deadline", + current->comm)); + break; + } + } + + 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 && + (try_stu || + scsi_eh_action(scmd, SUCCESS) == SUCCESS)) + scsi_eh_finish_cmd(scmd, done_q); + else + list_move_tail(&scmd->eh_entry, work_q); + } + } + return list_empty(work_q); +} + +/** + * 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; + enum scsi_disposition rtn = NEEDS_RETRY; + + for (i = 0; rtn == NEEDS_RETRY && i < 2; i++) + rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, + scmd->device->eh_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) { + if (scsi_host_eh_past_deadline(shost)) { + SCSI_LOG_ERROR_RECOVERY(3, + sdev_printk(KERN_INFO, sdev, + "%s: skip START_UNIT, past eh deadline\n", + current->comm)); + scsi_device_put(sdev); + break; + } + 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, + sdev_printk(KERN_INFO, sdev, + "%s: Sending START_UNIT\n", + current->comm)); + + 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_action(scmd, SUCCESS) == SUCCESS) + scsi_eh_finish_cmd(scmd, done_q); + } + } + } else { + SCSI_LOG_ERROR_RECOVERY(3, + sdev_printk(KERN_INFO, sdev, + "%s: START_UNIT failed\n", + current->comm)); + } + } + + 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; + enum scsi_disposition rtn; + + shost_for_each_device(sdev, shost) { + if (scsi_host_eh_past_deadline(shost)) { + SCSI_LOG_ERROR_RECOVERY(3, + sdev_printk(KERN_INFO, sdev, + "%s: skip BDR, past eh deadline\n", + current->comm)); + scsi_device_put(sdev); + break; + } + 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, + sdev_printk(KERN_INFO, sdev, + "%s: Sending BDR\n", current->comm)); + 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_action(scmd, rtn) != FAILED) + scsi_eh_finish_cmd(scmd, + done_q); + } + } + } else { + SCSI_LOG_ERROR_RECOVERY(3, + sdev_printk(KERN_INFO, sdev, + "%s: BDR failed\n", current->comm)); + } + } + + 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; + enum scsi_disposition rtn; + unsigned int id; + + if (scsi_host_eh_past_deadline(shost)) { + /* push back on work queue for further processing */ + list_splice_init(&check_list, work_q); + list_splice_init(&tmp_list, work_q); + SCSI_LOG_ERROR_RECOVERY(3, + shost_printk(KERN_INFO, shost, + "%s: Skip target reset, past eh deadline\n", + current->comm)); + return list_empty(work_q); + } + + scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry); + id = scmd_id(scmd); + + SCSI_LOG_ERROR_RECOVERY(3, + shost_printk(KERN_INFO, shost, + "%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, + shost_printk(KERN_INFO, shost, + "%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; + enum scsi_disposition 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++) { + if (scsi_host_eh_past_deadline(shost)) { + list_splice_init(&check_list, work_q); + SCSI_LOG_ERROR_RECOVERY(3, + shost_printk(KERN_INFO, shost, + "%s: skip BRST, past eh deadline\n", + current->comm)); + return list_empty(work_q); + } + + 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, + shost_printk(KERN_INFO, shost, + "%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, + shost_printk(KERN_INFO, shost, + "%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 + * @shost: host to be reset. + * @work_q: &list_head for pending commands. + * @done_q: &list_head for processed commands. + */ +static int scsi_eh_host_reset(struct Scsi_Host *shost, + struct list_head *work_q, + struct list_head *done_q) +{ + struct scsi_cmnd *scmd, *next; + LIST_HEAD(check_list); + enum scsi_disposition rtn; + + if (!list_empty(work_q)) { + scmd = list_entry(work_q->next, + struct scsi_cmnd, eh_entry); + + SCSI_LOG_ERROR_RECOVERY(3, + shost_printk(KERN_INFO, shost, + "%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, + shost_printk(KERN_INFO, shost, + "%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 pending 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; + struct scsi_device *sdev; + + 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"); + sdev = scmd->device; + + mutex_lock(&sdev->state_mutex); + scsi_device_set_state(sdev, SDEV_OFFLINE); + mutex_unlock(&sdev->state_mutex); + + scsi_eh_finish_cmd(scmd, done_q); + } + return; +} + +/** + * scsi_noretry_cmd - determine if command should be failed fast + * @scmd: SCSI cmd to examine. + */ +bool scsi_noretry_cmd(struct scsi_cmnd *scmd) +{ + struct request *req = scsi_cmd_to_rq(scmd); + + switch (host_byte(scmd->result)) { + case DID_OK: + break; + case DID_TIME_OUT: + goto check_type; + case DID_BUS_BUSY: + return !!(req->cmd_flags & REQ_FAILFAST_TRANSPORT); + case DID_PARITY: + return !!(req->cmd_flags & REQ_FAILFAST_DEV); + case DID_ERROR: + if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT) + return false; + fallthrough; + case DID_SOFT_ERROR: + return !!(req->cmd_flags & REQ_FAILFAST_DRIVER); + } + + /* Never retry commands aborted due to a duration limit timeout */ + if (scsi_ml_byte(scmd->result) == SCSIML_STAT_DL_TIMEOUT) + return true; + + if (!scsi_status_is_check_condition(scmd->result)) + return false; + +check_type: + /* + * assume caller has checked sense and determined + * the check condition was retryable. + */ + if (req->cmd_flags & REQ_FAILFAST_DEV || blk_rq_is_passthrough(req)) + return true; + + return false; +} + +/** + * 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. + */ +enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd) +{ + enum scsi_disposition 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, scmd_printk(KERN_INFO, scmd, + "%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_ABORT: + if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) { + set_host_byte(scmd, DID_TIME_OUT); + return SUCCESS; + } + fallthrough; + case DID_NO_CONNECT: + case DID_BAD_TARGET: + /* + * 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; + case DID_SOFT_ERROR: + /* + * 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) + */ + 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_TRANSPORT_MARGINAL: + /* + * caller has decided not to do retries on + * abort success, so send IO directly upwards + */ + return SUCCESS; + case DID_ERROR: + if (get_status_byte(scmd) == SAM_STAT_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; + } + + /* + * check the status byte to see if this indicates anything special. + */ + switch (get_status_byte(scmd)) { + case SAM_STAT_TASK_SET_FULL: + scsi_handle_queue_full(scmd->device); + /* + * the case of trying to send too many commands to a + * tagged queueing device. + */ + fallthrough; + case SAM_STAT_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 SAM_STAT_GOOD: + if (scmd->cmnd[0] == REPORT_LUNS) + scmd->device->sdev_target->expecting_lun_change = 0; + scsi_handle_queue_ramp_up(scmd->device); + if (scmd->sense_buffer && SCSI_SENSE_VALID(scmd)) + /* + * If we have sense data, call scsi_check_sense() in + * order to set the correct SCSI ML byte (if any). + * No point in checking the return value, since the + * command has already completed successfully. + */ + scsi_check_sense(scmd); + fallthrough; + case SAM_STAT_COMMAND_TERMINATED: + return SUCCESS; + case SAM_STAT_TASK_ABORTED: + goto maybe_retry; + case SAM_STAT_CHECK_CONDITION: + rtn = scsi_check_sense(scmd); + if (rtn == NEEDS_RETRY) + goto maybe_retry; + /* 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 SAM_STAT_CONDITION_MET: + case SAM_STAT_INTERMEDIATE: + case SAM_STAT_INTERMEDIATE_CONDITION_MET: + case SAM_STAT_ACA_ACTIVE: + /* + * who knows? FIXME(eric) + */ + return SUCCESS; + + case SAM_STAT_RESERVATION_CONFLICT: + sdev_printk(KERN_INFO, scmd->device, + "reservation conflict\n"); + set_scsi_ml_byte(scmd, SCSIML_STAT_RESV_CONFLICT); + return SUCCESS; /* causes immediate i/o error */ + } + 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 (scsi_cmd_retry_allowed(scmd) && !scsi_noretry_cmd(scmd)) { + return NEEDS_RETRY; + } else { + /* + * no more retries - report this one back to upper level. + */ + return SUCCESS; + } +} + +static enum rq_end_io_ret eh_lock_door_done(struct request *req, + blk_status_t status) +{ + blk_mq_free_request(req); + return RQ_END_IO_NONE; +} + +/** + * 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 scsi_cmnd *scmd; + struct request *req; + + req = scsi_alloc_request(sdev->request_queue, REQ_OP_DRV_IN, 0); + if (IS_ERR(req)) + return; + scmd = blk_mq_rq_to_pdu(req); + + scmd->cmnd[0] = ALLOW_MEDIUM_REMOVAL; + scmd->cmnd[1] = 0; + scmd->cmnd[2] = 0; + scmd->cmnd[3] = 0; + scmd->cmnd[4] = SCSI_REMOVAL_PREVENT; + scmd->cmnd[5] = 0; + scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]); + scmd->allowed = 5; + + req->rq_flags |= RQF_QUIET; + req->timeout = 10 * HZ; + req->end_io = eh_lock_door_done; + + blk_execute_rq_nowait(req, true); +} + +/** + * 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->was_reset && sdev->locked) { + scsi_eh_lock_door(sdev); + sdev->was_reset = 0; + } + } + + /* + * 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, + shost_printk(KERN_INFO, shost, "waking up host to restart\n")); + + 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); + + /* + * if eh is active and host_eh_scheduled is pending we need to re-run + * recovery. we do this check after scsi_run_host_queues() to allow + * everything pent up since the last eh run a chance to make forward + * progress before we sync again. Either we'll immediately re-run + * recovery or scsi_device_unbusy() will wake us again when these + * pending commands complete. + */ + spin_lock_irqsave(shost->host_lock, flags); + if (shost->host_eh_scheduled) + if (scsi_host_set_state(shost, SHOST_RECOVERY)) + WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)); + spin_unlock_irqrestore(shost->host_lock, flags); +} + +/** + * 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(shost, 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) { + struct scsi_device *sdev = scmd->device; + + list_del_init(&scmd->eh_entry); + if (scsi_device_online(sdev) && !scsi_noretry_cmd(scmd) && + scsi_cmd_retry_allowed(scmd) && + scsi_eh_should_retry_cmd(scmd)) { + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "%s: flush retry cmd\n", + current->comm)); + scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY); + blk_mq_kick_requeue_list(sdev->request_queue); + } else { + /* + * If just we got sense for the device (called + * scsi_eh_get_sense), scmd->result is already + * set, do not set DID_TIME_OUT. + */ + if (!scmd->result && + !(scmd->flags & SCMD_FORCE_EH_SUCCESS)) + scmd->result |= (DID_TIME_OUT << 16); + SCSI_LOG_ERROR_RECOVERY(3, + scmd_printk(KERN_INFO, scmd, + "%s: flush finish cmd\n", + current->comm)); + 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)) + scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q); + + spin_lock_irqsave(shost->host_lock, flags); + if (shost->eh_deadline != -1) + shost->last_reset = 0; + spin_unlock_irqrestore(shost->host_lock, flags); + 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. + */ + while (true) { + /* + * The sequence in kthread_stop() sets the stop flag first + * then wakes the process. To avoid missed wakeups, the task + * should always be in a non running state before the stop + * flag is checked + */ + set_current_state(TASK_INTERRUPTIBLE); + if (kthread_should_stop()) + break; + + if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) || + shost->host_failed != scsi_host_busy(shost)) { + SCSI_LOG_ERROR_RECOVERY(1, + shost_printk(KERN_INFO, shost, + "scsi_eh_%d: sleeping\n", + shost->host_no)); + schedule(); + continue; + } + + __set_current_state(TASK_RUNNING); + SCSI_LOG_ERROR_RECOVERY(1, + shost_printk(KERN_INFO, shost, + "scsi_eh_%d: waking up %d/%d/%d\n", + shost->host_no, shost->host_eh_scheduled, + shost->host_failed, + scsi_host_busy(shost))); + + /* + * 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 (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) { + SCSI_LOG_ERROR_RECOVERY(1, + shost_printk(KERN_ERR, shost, + "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); + + /* All scmds have been handled */ + shost->host_failed = 0; + + /* + * 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); + if (!shost->eh_noresume) + scsi_autopm_put_host(shost); + } + __set_current_state(TASK_RUNNING); + + SCSI_LOG_ERROR_RECOVERY(1, + shost_printk(KERN_INFO, shost, + "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); + +/** + * scsi_ioctl_reset: explicitly reset a host/bus/target/device + * @dev: scsi_device to operate on + * @arg: reset type (see sg.h) + */ +int +scsi_ioctl_reset(struct scsi_device *dev, int __user *arg) +{ + struct scsi_cmnd *scmd; + struct Scsi_Host *shost = dev->host; + struct request *rq; + unsigned long flags; + int error = 0, val; + enum scsi_disposition rtn; + + if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO)) + return -EACCES; + + error = get_user(val, arg); + if (error) + return error; + + if (scsi_autopm_get_host(shost) < 0) + return -EIO; + + error = -EIO; + rq = kzalloc(sizeof(struct request) + sizeof(struct scsi_cmnd) + + shost->hostt->cmd_size, GFP_KERNEL); + if (!rq) + goto out_put_autopm_host; + blk_rq_init(NULL, rq); + + scmd = (struct scsi_cmnd *)(rq + 1); + scsi_init_command(dev, scmd); + + scmd->submitter = SUBMITTED_BY_SCSI_RESET_IOCTL; + scmd->flags |= SCMD_LAST; + 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 (val & ~SG_SCSI_RESET_NO_ESCALATE) { + case SG_SCSI_RESET_NOTHING: + rtn = SUCCESS; + break; + case SG_SCSI_RESET_DEVICE: + rtn = scsi_try_bus_device_reset(scmd); + if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE)) + break; + fallthrough; + case SG_SCSI_RESET_TARGET: + rtn = scsi_try_target_reset(scmd); + if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE)) + break; + fallthrough; + case SG_SCSI_RESET_BUS: + rtn = scsi_try_bus_reset(scmd); + if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE)) + break; + fallthrough; + case SG_SCSI_RESET_HOST: + rtn = scsi_try_host_reset(scmd); + if (rtn == SUCCESS) + break; + fallthrough; + default: + rtn = FAILED; + break; + } + + error = (rtn == SUCCESS) ? 0 : -EIO; + + 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, + shost_printk(KERN_INFO, shost, + "waking up host to restart after TMF\n")); + + wake_up(&shost->host_wait); + scsi_run_host_queues(shost); + + kfree(rq); + +out_put_autopm_host: + scsi_autopm_put_host(shost); + return error; +} + +bool scsi_command_normalize_sense(const 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_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: + * true if information field found, false if not found. + */ +bool scsi_get_sense_info_fld(const u8 *sense_buffer, int sb_len, + u64 *info_out) +{ + const u8 * ucp; + + if (sb_len < 7) + return false; + switch (sense_buffer[0] & 0x7f) { + case 0x70: + case 0x71: + if (sense_buffer[0] & 0x80) { + *info_out = get_unaligned_be32(&sense_buffer[3]); + return true; + } + return false; + case 0x72: + case 0x73: + ucp = scsi_sense_desc_find(sense_buffer, sb_len, + 0 /* info desc */); + if (ucp && (0xa == ucp[1])) { + *info_out = get_unaligned_be64(&ucp[4]); + return true; + } + return false; + default: + return false; + } +} +EXPORT_SYMBOL(scsi_get_sense_info_fld); |