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[S390] cio: always query all paths on path verification.
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Reappearing channel paths are sometimes not utilized by CCW devices
because path verification incorrectly relies on path-operational-mask
information which is not updated until a channel path has been used
again.
Modify path verification procedure to always query all available paths
to a device.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Peter Oberparleiter authored and Martin Schwidefsky committed Sep 20, 2006
1 parent e0e32c8 commit 28bdc6f
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Showing 5 changed files with 68 additions and 61 deletions.
2 changes: 1 addition & 1 deletion drivers/s390/cio/chsc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -256,7 +256,7 @@ s390_subchannel_remove_chpid(struct device *dev, void *data)
/* trigger path verification. */
if (sch->driver && sch->driver->verify)
sch->driver->verify(&sch->dev);
else if (sch->vpm == mask)
else if (sch->lpm == mask)
goto out_unreg;
out_unlock:
spin_unlock_irq(&sch->lock);
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5 changes: 1 addition & 4 deletions drivers/s390/cio/cio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -569,10 +569,7 @@ cio_validate_subchannel (struct subchannel *sch, struct subchannel_id schid)
sch->opm = 0xff;
if (!cio_is_console(sch->schid))
chsc_validate_chpids(sch);
sch->lpm = sch->schib.pmcw.pim &
sch->schib.pmcw.pam &
sch->schib.pmcw.pom &
sch->opm;
sch->lpm = sch->schib.pmcw.pam & sch->opm;

CIO_DEBUG(KERN_INFO, 0,
"Detected device %04x on subchannel 0.%x.%04X"
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39 changes: 23 additions & 16 deletions drivers/s390/cio/device_fsm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -232,10 +232,7 @@ ccw_device_recog_done(struct ccw_device *cdev, int state)
*/
old_lpm = sch->lpm;
stsch(sch->schid, &sch->schib);
sch->lpm = sch->schib.pmcw.pim &
sch->schib.pmcw.pam &
sch->schib.pmcw.pom &
sch->opm;
sch->lpm = sch->schib.pmcw.pam & sch->opm;
/* Check since device may again have become not operational. */
if (!sch->schib.pmcw.dnv)
state = DEV_STATE_NOT_OPER;
Expand Down Expand Up @@ -455,8 +452,8 @@ ccw_device_sense_pgid_done(struct ccw_device *cdev, int err)
return;
}
/* Start Path Group verification. */
sch->vpm = 0; /* Start with no path groups set. */
cdev->private->state = DEV_STATE_VERIFY;
cdev->private->flags.doverify = 0;
ccw_device_verify_start(cdev);
}

Expand Down Expand Up @@ -556,7 +553,19 @@ ccw_device_nopath_notify(void *data)
void
ccw_device_verify_done(struct ccw_device *cdev, int err)
{
cdev->private->flags.doverify = 0;
struct subchannel *sch;

sch = to_subchannel(cdev->dev.parent);
/* Update schib - pom may have changed. */
stsch(sch->schid, &sch->schib);
/* Update lpm with verified path mask. */
sch->lpm = sch->vpm;
/* Repeat path verification? */
if (cdev->private->flags.doverify) {
cdev->private->flags.doverify = 0;
ccw_device_verify_start(cdev);
return;
}
switch (err) {
case -EOPNOTSUPP: /* path grouping not supported, just set online. */
cdev->private->options.pgroup = 0;
Expand Down Expand Up @@ -614,6 +623,7 @@ ccw_device_online(struct ccw_device *cdev)
if (!cdev->private->options.pgroup) {
/* Start initial path verification. */
cdev->private->state = DEV_STATE_VERIFY;
cdev->private->flags.doverify = 0;
ccw_device_verify_start(cdev);
return 0;
}
Expand Down Expand Up @@ -660,7 +670,6 @@ ccw_device_offline(struct ccw_device *cdev)
/* Are we doing path grouping? */
if (!cdev->private->options.pgroup) {
/* No, set state offline immediately. */
sch->vpm = 0;
ccw_device_done(cdev, DEV_STATE_OFFLINE);
return 0;
}
Expand Down Expand Up @@ -781,6 +790,7 @@ ccw_device_online_verify(struct ccw_device *cdev, enum dev_event dev_event)
}
/* Device is idle, we can do the path verification. */
cdev->private->state = DEV_STATE_VERIFY;
cdev->private->flags.doverify = 0;
ccw_device_verify_start(cdev);
}

Expand Down Expand Up @@ -1043,9 +1053,9 @@ ccw_device_wait4io_timeout(struct ccw_device *cdev, enum dev_event dev_event)
}

static void
ccw_device_wait4io_verify(struct ccw_device *cdev, enum dev_event dev_event)
ccw_device_delay_verify(struct ccw_device *cdev, enum dev_event dev_event)
{
/* When the I/O has terminated, we have to start verification. */
/* Start verification after current task finished. */
cdev->private->flags.doverify = 1;
}

Expand Down Expand Up @@ -1111,10 +1121,7 @@ device_trigger_reprobe(struct subchannel *sch)
* The pim, pam, pom values may not be accurate, but they are the best
* we have before performing device selection :/
*/
sch->lpm = sch->schib.pmcw.pim &
sch->schib.pmcw.pam &
sch->schib.pmcw.pom &
sch->opm;
sch->lpm = sch->schib.pmcw.pam & sch->opm;
/* Re-set some bits in the pmcw that were lost. */
sch->schib.pmcw.isc = 3;
sch->schib.pmcw.csense = 1;
Expand Down Expand Up @@ -1238,7 +1245,7 @@ fsm_func_t *dev_jumptable[NR_DEV_STATES][NR_DEV_EVENTS] = {
[DEV_EVENT_NOTOPER] = ccw_device_online_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_verify_irq,
[DEV_EVENT_TIMEOUT] = ccw_device_onoff_timeout,
[DEV_EVENT_VERIFY] = ccw_device_nop,
[DEV_EVENT_VERIFY] = ccw_device_delay_verify,
},
[DEV_STATE_ONLINE] = {
[DEV_EVENT_NOTOPER] = ccw_device_online_notoper,
Expand Down Expand Up @@ -1281,7 +1288,7 @@ fsm_func_t *dev_jumptable[NR_DEV_STATES][NR_DEV_EVENTS] = {
[DEV_EVENT_NOTOPER] = ccw_device_online_notoper,
[DEV_EVENT_INTERRUPT] = ccw_device_wait4io_irq,
[DEV_EVENT_TIMEOUT] = ccw_device_wait4io_timeout,
[DEV_EVENT_VERIFY] = ccw_device_wait4io_verify,
[DEV_EVENT_VERIFY] = ccw_device_delay_verify,
},
[DEV_STATE_QUIESCE] = {
[DEV_EVENT_NOTOPER] = ccw_device_quiesce_done,
Expand All @@ -1294,7 +1301,7 @@ fsm_func_t *dev_jumptable[NR_DEV_STATES][NR_DEV_EVENTS] = {
[DEV_EVENT_NOTOPER] = ccw_device_nop,
[DEV_EVENT_INTERRUPT] = ccw_device_start_id,
[DEV_EVENT_TIMEOUT] = ccw_device_bug,
[DEV_EVENT_VERIFY] = ccw_device_nop,
[DEV_EVENT_VERIFY] = ccw_device_start_id,
},
[DEV_STATE_DISCONNECTED_SENSE_ID] = {
[DEV_EVENT_NOTOPER] = ccw_device_recog_notoper,
Expand Down
2 changes: 1 addition & 1 deletion drivers/s390/cio/device_ops.c
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Original file line number Diff line number Diff line change
Expand Up @@ -256,7 +256,7 @@ ccw_device_get_path_mask(struct ccw_device *cdev)
if (!sch)
return 0;
else
return sch->vpm;
return sch->lpm;
}

static void
Expand Down
81 changes: 42 additions & 39 deletions drivers/s390/cio/device_pgid.c
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Original file line number Diff line number Diff line change
Expand Up @@ -245,18 +245,17 @@ __ccw_device_do_pgid(struct ccw_device *cdev, __u8 func)
memset(&cdev->private->irb, 0, sizeof(struct irb));

/* Try multiple times. */
ret = -ENODEV;
ret = -EACCES;
if (cdev->private->iretry > 0) {
cdev->private->iretry--;
ret = cio_start (sch, cdev->private->iccws,
cdev->private->imask);
/* ret is 0, -EBUSY, -EACCES or -ENODEV */
if ((ret != -EACCES) && (ret != -ENODEV))
/* We expect an interrupt in case of success or busy
* indication. */
if ((ret == 0) || (ret == -EBUSY))
return ret;
}
/* PGID command failed on this path. Switch it off. */
sch->lpm &= ~cdev->private->imask;
sch->vpm &= ~cdev->private->imask;
/* PGID command failed on this path. */
CIO_MSG_EVENT(2, "SPID - Device %04x on Subchannel "
"0.%x.%04x, lpm %02X, became 'not operational'\n",
cdev->private->devno, sch->schid.ssid,
Expand Down Expand Up @@ -286,18 +285,17 @@ static int __ccw_device_do_nop(struct ccw_device *cdev)
memset(&cdev->private->irb, 0, sizeof(struct irb));

/* Try multiple times. */
ret = -ENODEV;
ret = -EACCES;
if (cdev->private->iretry > 0) {
cdev->private->iretry--;
ret = cio_start (sch, cdev->private->iccws,
cdev->private->imask);
/* ret is 0, -EBUSY, -EACCES or -ENODEV */
if ((ret != -EACCES) && (ret != -ENODEV))
/* We expect an interrupt in case of success or busy
* indication. */
if ((ret == 0) || (ret == -EBUSY))
return ret;
}
/* nop command failed on this path. Switch it off. */
sch->lpm &= ~cdev->private->imask;
sch->vpm &= ~cdev->private->imask;
/* nop command failed on this path. */
CIO_MSG_EVENT(2, "NOP - Device %04x on Subchannel "
"0.%x.%04x, lpm %02X, became 'not operational'\n",
cdev->private->devno, sch->schid.ssid,
Expand Down Expand Up @@ -372,27 +370,32 @@ static void
__ccw_device_verify_start(struct ccw_device *cdev)
{
struct subchannel *sch;
__u8 imask, func;
__u8 func;
int ret;

sch = to_subchannel(cdev->dev.parent);
while (sch->vpm != sch->lpm) {
/* Find first unequal bit in vpm vs. lpm */
for (imask = 0x80; imask != 0; imask >>= 1)
if ((sch->vpm & imask) != (sch->lpm & imask))
break;
cdev->private->imask = imask;
/* Repeat for all paths. */
for (; cdev->private->imask; cdev->private->imask >>= 1,
cdev->private->iretry = 5) {
if ((cdev->private->imask & sch->schib.pmcw.pam) == 0)
/* Path not available, try next. */
continue;
if (cdev->private->options.pgroup) {
func = (sch->vpm & imask) ?
SPID_FUNC_RESIGN : SPID_FUNC_ESTABLISH;
if (sch->opm & cdev->private->imask)
func = SPID_FUNC_ESTABLISH;
else
func = SPID_FUNC_RESIGN;
ret = __ccw_device_do_pgid(cdev, func);
} else
ret = __ccw_device_do_nop(cdev);
/* We expect an interrupt in case of success or busy
* indication. */
if (ret == 0 || ret == -EBUSY)
return;
cdev->private->iretry = 5;
/* Permanent path failure, try next. */
}
ccw_device_verify_done(cdev, (sch->lpm != 0) ? 0 : -ENODEV);
/* Done with all paths. */
ccw_device_verify_done(cdev, (sch->vpm != 0) ? 0 : -ENODEV);
}

/*
Expand Down Expand Up @@ -421,14 +424,14 @@ ccw_device_verify_irq(struct ccw_device *cdev, enum dev_event dev_event)
else
ret = __ccw_device_check_nop(cdev);
memset(&cdev->private->irb, 0, sizeof(struct irb));

switch (ret) {
/* 0, -ETIME, -EAGAIN, -EOPNOTSUPP or -EACCES */
case 0:
/* Establish or Resign Path Group done. Update vpm. */
if ((sch->lpm & cdev->private->imask) != 0)
sch->vpm |= cdev->private->imask;
else
sch->vpm &= ~cdev->private->imask;
/* Path verification ccw finished successfully, update lpm. */
sch->vpm |= sch->opm & cdev->private->imask;
/* Go on with next path. */
cdev->private->imask >>= 1;
cdev->private->iretry = 5;
__ccw_device_verify_start(cdev);
break;
Expand All @@ -441,6 +444,10 @@ ccw_device_verify_irq(struct ccw_device *cdev, enum dev_event dev_event)
cdev->private->options.pgroup = 0;
else
cdev->private->flags.pgid_single = 1;
/* Retry */
sch->vpm = 0;
cdev->private->imask = 0x80;
cdev->private->iretry = 5;
/* fall through. */
case -EAGAIN: /* Try again. */
__ccw_device_verify_start(cdev);
Expand All @@ -449,8 +456,7 @@ ccw_device_verify_irq(struct ccw_device *cdev, enum dev_event dev_event)
ccw_device_verify_done(cdev, -ETIME);
break;
case -EACCES: /* channel is not operational. */
sch->lpm &= ~cdev->private->imask;
sch->vpm &= ~cdev->private->imask;
cdev->private->imask >>= 1;
cdev->private->iretry = 5;
__ccw_device_verify_start(cdev);
break;
Expand All @@ -463,19 +469,17 @@ ccw_device_verify_start(struct ccw_device *cdev)
struct subchannel *sch = to_subchannel(cdev->dev.parent);

cdev->private->flags.pgid_single = 0;
cdev->private->imask = 0x80;
cdev->private->iretry = 5;
/*
* Update sch->lpm with current values to catch paths becoming
* available again.
*/

/* Start with empty vpm. */
sch->vpm = 0;

/* Get current pam. */
if (stsch(sch->schid, &sch->schib)) {
ccw_device_verify_done(cdev, -ENODEV);
return;
}
sch->lpm = sch->schib.pmcw.pim &
sch->schib.pmcw.pam &
sch->schib.pmcw.pom &
sch->opm;
__ccw_device_verify_start(cdev);
}

Expand Down Expand Up @@ -524,7 +528,6 @@ ccw_device_disband_irq(struct ccw_device *cdev, enum dev_event dev_event)
switch (ret) {
/* 0, -ETIME, -EAGAIN, -EOPNOTSUPP or -EACCES */
case 0: /* disband successful. */
sch->vpm = 0;
ccw_device_disband_done(cdev, ret);
break;
case -EOPNOTSUPP:
Expand Down

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