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[SCSI] libsas: Handle SCSI commands that complete with failure codes
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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: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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Darrick J. Wong authored and James Bottomley committed Jan 27, 2007
1 parent dca84e4 commit ad68923
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Showing 2 changed files with 105 additions and 44 deletions.
148 changes: 104 additions & 44 deletions drivers/scsi/libsas/sas_scsi_host.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -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;

/* Directly attached device */
if (!pdev)
return dev->port->phy;

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);
/* 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;
}

return tmf_resp;
BUG_ON(!exphy);
return exphy->phy;
}

void sas_scsi_recover_host(struct Scsi_Host *shost)
/* 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);
Expand All @@ -457,14 +484,14 @@ void sas_scsi_recover_host(struct Scsi_Host *shost)
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);
Expand All @@ -476,8 +503,8 @@ void sas_scsi_recover_host(struct Scsi_Host *shost)
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 */
Expand All @@ -491,8 +518,8 @@ void sas_scsi_recover_host(struct Scsi_Host *shost)
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 :-) */
Expand All @@ -506,8 +533,8 @@ void sas_scsi_recover_host(struct Scsi_Host *shost)
"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;
}
Expand All @@ -520,7 +547,7 @@ void sas_scsi_recover_host(struct Scsi_Host *shost)
"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;
}
}
Expand All @@ -535,21 +562,53 @@ void sas_scsi_recover_host(struct Scsi_Host *shost)

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)
Expand Down Expand Up @@ -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);
1 change: 1 addition & 0 deletions include/scsi/libsas.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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_ */

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