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Commit ad689233 authored by Darrick J. Wong's avatar Darrick J. Wong Committed by James Bottomley
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[SCSI] libsas: Handle SCSI commands that complete with failure codes 



This patch moves the code that handles SAS failures out of the main EH
function and into a separate function.  It also detects commands that have
no sas_task (i.e. they completed, but with error data) and sends them into
scsi_error for processing.  This allows us to handle SCSI errors (and
enables auto-spinup as a side effect) instead of dropping them on the
floor and falling into an infinite loop.  It also requires the
implementation of a device reset function, which the SAS failure code has
been modified to employ for REQ_DEVICE_RESET.

Signed-off-by: default avatarDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent dca84e46

drivers/scsi/libsas/sas_scsi_host.c

+104 −44
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
#include <scsi/scsi_transport_sas.h>

#include "../scsi_sas_internal.h"

#include "../scsi_transport_api.h"

#include "../scsi_priv.h"



#include <linux/err.h>

#include <linux/blkdev.h>
@@ -396,54 +397,80 @@ static int sas_recover_I_T(struct domain_device *dev) 
	return res;

}



static int eh_reset_phy_helper(struct sas_phy *phy)

/* Find the sas_phy that's attached to this device */

struct sas_phy *find_local_sas_phy(struct domain_device *dev)

{

	int tmf_resp;

	struct domain_device *pdev = dev->parent;

	struct ex_phy *exphy = NULL;

	int i;



	tmf_resp = sas_phy_reset(phy, 1);

	if (tmf_resp)

		SAS_DPRINTK("Hard reset of phy %d failed 0x%x\n",

			    phy->identify.phy_identifier,

			    tmf_resp);

	/* Directly attached device */

	if (!pdev)

		return dev->port->phy;



	return tmf_resp;

	/* Otherwise look in the expander */

	for (i = 0; i < pdev->ex_dev.num_phys; i++)

		if (!memcmp(dev->sas_addr,

			    pdev->ex_dev.ex_phy[i].attached_sas_addr,

			    SAS_ADDR_SIZE)) {

			exphy = &pdev->ex_dev.ex_phy[i];

			break;

		}



void sas_scsi_recover_host(struct Scsi_Host *shost)

	BUG_ON(!exphy);

	return exphy->phy;

}



/* Attempt to send a target reset message to a device */

int sas_eh_device_reset_handler(struct scsi_cmnd *cmd)

{

	struct domain_device *dev = cmd_to_domain_dev(cmd);

	struct sas_phy *phy = find_local_sas_phy(dev);

	int res;



	res = sas_phy_reset(phy, 1);

	if (res)

		SAS_DPRINTK("Device reset of %s failed 0x%x\n",

			    phy->dev.kobj.k_name,

			    res);

	if (res == TMF_RESP_FUNC_SUCC || res == TMF_RESP_FUNC_COMPLETE)

		return SUCCESS;



	return FAILED;

}



/* Try to reset a device */

static int try_to_reset_cmd_device(struct Scsi_Host *shost,

				   struct scsi_cmnd *cmd)

{

	if (!shost->hostt->eh_device_reset_handler)

		return FAILED;



	return shost->hostt->eh_device_reset_handler(cmd);

}



static int sas_eh_handle_sas_errors(struct Scsi_Host *shost,

				    struct list_head *work_q,

				    struct list_head *done_q)

{

	struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);

	unsigned long flags;

	LIST_HEAD(error_q);

	struct scsi_cmnd *cmd, *n;

	enum task_disposition res = TASK_IS_DONE;

	int tmf_resp, need_reset;

	struct sas_internal *i = to_sas_internal(shost->transportt);

	struct sas_phy *task_sas_phy = NULL;



	spin_lock_irqsave(shost->host_lock, flags);

	list_splice_init(&shost->eh_cmd_q, &error_q);

	spin_unlock_irqrestore(shost->host_lock, flags);



	SAS_DPRINTK("Enter %s\n", __FUNCTION__);

	unsigned long flags;

	struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);



	/* All tasks on this list were marked SAS_TASK_STATE_ABORTED

	 * by sas_scsi_timed_out() callback.

	 */

Again:

	SAS_DPRINTK("going over list...\n");

	list_for_each_entry_safe(cmd, n, &error_q, eh_entry) {

	list_for_each_entry_safe(cmd, n, work_q, eh_entry) {

		struct sas_task *task = TO_SAS_TASK(cmd);

		list_del_init(&cmd->eh_entry);



		if (!task) {

			SAS_DPRINTK("%s: taskless cmd?!\n", __FUNCTION__);

		if (!task)

			continue;

		}



		list_del_init(&cmd->eh_entry);



		spin_lock_irqsave(&task->task_state_lock, flags);

		need_reset = task->task_state_flags & SAS_TASK_NEED_DEV_RESET;

		if (need_reset)

			task_sas_phy = task->dev->port->phy;

		spin_unlock_irqrestore(&task->task_state_lock, flags);



		SAS_DPRINTK("trying to find task 0x%p\n", task);
@@ -457,14 +484,14 @@ Again: 
				    task);

			task->task_done(task);

			if (need_reset)

				eh_reset_phy_helper(task_sas_phy);

				try_to_reset_cmd_device(shost, cmd);

			continue;

		case TASK_IS_ABORTED:

			SAS_DPRINTK("%s: task 0x%p is aborted\n",

				    __FUNCTION__, task);

			task->task_done(task);

			if (need_reset)

				eh_reset_phy_helper(task_sas_phy);

				try_to_reset_cmd_device(shost, cmd);

			continue;

		case TASK_IS_AT_LU:

			SAS_DPRINTK("task 0x%p is at LU: lu recover\n", task);
@@ -476,8 +503,8 @@ Again: 
					    cmd->device->lun);

				task->task_done(task);

				if (need_reset)

					eh_reset_phy_helper(task_sas_phy);

				sas_scsi_clear_queue_lu(&error_q, cmd);

					try_to_reset_cmd_device(shost, cmd);

				sas_scsi_clear_queue_lu(work_q, cmd);

				goto Again;

			}

			/* fallthrough */
@@ -491,8 +518,8 @@ Again: 
					    SAS_ADDR(task->dev->sas_addr));

				task->task_done(task);

				if (need_reset)

					eh_reset_phy_helper(task_sas_phy);

				sas_scsi_clear_queue_I_T(&error_q, task->dev);

					try_to_reset_cmd_device(shost, cmd);

				sas_scsi_clear_queue_I_T(work_q, task->dev);

				goto Again;

			}

			/* Hammer time :-) */
@@ -506,8 +533,8 @@ Again: 
						    "succeeded\n", port->id);

					task->task_done(task);

					if (need_reset)

						eh_reset_phy_helper(task_sas_phy);

					sas_scsi_clear_queue_port(&error_q,

						try_to_reset_cmd_device(shost, cmd);

					sas_scsi_clear_queue_port(work_q,

								  port);

					goto Again;

				}
@@ -520,7 +547,7 @@ Again: 
						    "succeeded\n");

					task->task_done(task);

					if (need_reset)

						eh_reset_phy_helper(task_sas_phy);

						try_to_reset_cmd_device(shost, cmd);

					goto out;

				}

			}
@@ -535,21 +562,53 @@ Again: 


			task->task_done(task);

			if (need_reset)

				eh_reset_phy_helper(task_sas_phy);

				try_to_reset_cmd_device(shost, cmd);

			goto clear_q;

		}

	}

out:

	scsi_eh_flush_done_q(&ha->eh_done_q);

	SAS_DPRINTK("--- Exit %s\n", __FUNCTION__);

	return;

	return list_empty(work_q);

clear_q:

	SAS_DPRINTK("--- Exit %s -- clear_q\n", __FUNCTION__);

	list_for_each_entry_safe(cmd, n, &error_q, eh_entry) {

	list_for_each_entry_safe(cmd, n, work_q, eh_entry) {

		struct sas_task *task = TO_SAS_TASK(cmd);

		list_del_init(&cmd->eh_entry);

		task->task_done(task);

	}

	return list_empty(work_q);

}



void sas_scsi_recover_host(struct Scsi_Host *shost)

{

	struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);

	unsigned long flags;

	LIST_HEAD(eh_work_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);



	SAS_DPRINTK("Enter %s\n", __FUNCTION__);

	/*

	 * Deal with commands that still have SAS tasks (i.e. they didn't

	 * complete via the normal sas_task completion mechanism)

	 */

	if (sas_eh_handle_sas_errors(shost, &eh_work_q, &ha->eh_done_q))

		goto out;



	/*

	 * Now deal with SCSI commands that completed ok but have a an error

	 * code (and hopefully sense data) attached.  This is roughly what

	 * scsi_unjam_host does, but we skip scsi_eh_abort_cmds because any

	 * command we see here has no sas_task and is thus unknown to the HA.

	 */

	if (!scsi_eh_get_sense(&eh_work_q, &ha->eh_done_q))

		scsi_eh_ready_devs(shost, &eh_work_q, &ha->eh_done_q);



out:

	scsi_eh_flush_done_q(&ha->eh_done_q);

	SAS_DPRINTK("--- Exit %s\n", __FUNCTION__);

	return;

}



enum scsi_eh_timer_return sas_scsi_timed_out(struct scsi_cmnd *cmd)
@@ -914,3 +973,4 @@ EXPORT_SYMBOL_GPL(__sas_task_abort); 
EXPORT_SYMBOL_GPL(sas_task_abort);

EXPORT_SYMBOL_GPL(sas_phy_reset);

EXPORT_SYMBOL_GPL(sas_phy_enable);

EXPORT_SYMBOL_GPL(sas_eh_device_reset_handler);

include/scsi/libsas.h

+1 −0
Original line number Diff line number Diff line
@@ -660,5 +660,6 @@ void sas_init_dev(struct domain_device *); 


void sas_task_abort(struct sas_task *);

int __sas_task_abort(struct sas_task *);

int sas_eh_device_reset_handler(struct scsi_cmnd *cmd);



#endif /* _SASLIB_H_ */