Martin Schwidefsky
2006-09-18T14:15:01Z

From: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>

[S390] cio: always query all paths on path verification.

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>
---

drivers/s390/cio/chsc.c | 2 -
drivers/s390/cio/cio.c | 5 --
drivers/s390/cio/device_fsm.c | 39 +++++++++++--------
drivers/s390/cio/device_ops.c | 2 -
drivers/s390/cio/device_pgid.c | 81 +++++++++++++++++++++--------------------
5 files changed, 68 insertions(+), 61 deletions(-)

diff -urpN linux-2.6/drivers/s390/cio/chsc.c linux-2.6-patched/drivers/s390/cio/chsc.c
--- linux-2.6/drivers/s390/cio/chsc.c 2006-09-18 14:12:00.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/chsc.c 2006-09-18 14:12:02.000000000 +0200
@@ -256,7 +256,7 @@ s390_subchannel_remove_chpid(struct devi
/* 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);
diff -urpN linux-2.6/drivers/s390/cio/cio.c linux-2.6-patched/drivers/s390/cio/cio.c
--- linux-2.6/drivers/s390/cio/cio.c 2006-09-18 14:12:02.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/cio.c 2006-09-18 14:12:02.000000000 +0200
@@ -569,10 +569,7 @@ cio_validate_subchannel (struct subchann
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"
diff -urpN linux-2.6/drivers/s390/cio/device_fsm.c linux-2.6-patched/drivers/s390/cio/device_fsm.c
--- linux-2.6/drivers/s390/cio/device_fsm.c 2006-09-18 14:11:43.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/device_fsm.c 2006-09-18 14:12:02.000000000 +0200
@@ -232,10 +232,7 @@ ccw_device_recog_done(struct ccw_device
*/
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;
@@ -455,8 +452,8 @@ ccw_device_sense_pgid_done(struct ccw_de
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);
}

@@ -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;
@@ -614,6 +623,7 @@ ccw_device_online(struct ccw_device *cde
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;
}
@@ -660,7 +670,6 @@ ccw_device_offline(struct ccw_device *cd
/* 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;
}
@@ -781,6 +790,7 @@ ccw_device_online_verify(struct ccw_devi
}
/* 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);
}

@@ -1043,9 +1053,9 @@ ccw_device_wait4io_timeout(struct ccw_de
}

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;
}

@@ -1111,10 +1121,7 @@ device_trigger_reprobe(struct subchannel
* 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;
@@ -1238,7 +1245,7 @@ fsm_func_t *dev_jumptable[NR_DEV_STATES]
[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,
@@ -1281,7 +1288,7 @@ fsm_func_t *dev_jumptable[NR_DEV_STATES]
[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,
@@ -1294,7 +1301,7 @@ fsm_func_t *dev_jumptable[NR_DEV_STATES]
[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,
diff -urpN linux-2.6/drivers/s390/cio/device_ops.c linux-2.6-patched/drivers/s390/cio/device_ops.c
--- linux-2.6/drivers/s390/cio/device_ops.c 2006-09-18 14:12:02.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/device_ops.c 2006-09-18 14:12:02.000000000 +0200
@@ -256,7 +256,7 @@ ccw_device_get_path_mask(struct ccw_devi
if (!sch)
return 0;
else
- return sch->vpm;
+ return sch->lpm;
}

static void
diff -urpN linux-2.6/drivers/s390/cio/device_pgid.c linux-2.6-patched/drivers/s390/cio/device_pgid.c
--- linux-2.6/drivers/s390/cio/device_pgid.c 2006-09-18 14:11:04.000000000 +0200
+++ linux-2.6-patched/drivers/s390/cio/device_pgid.c 2006-09-18 14:12:02.000000000 +0200
@@ -245,18 +245,17 @@ __ccw_device_do_pgid(struct ccw_device *
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,
@@ -286,18 +285,17 @@ static int __ccw_device_do_nop(struct cc
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,
@@ -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);
}

/*
@@ -421,14 +424,14 @@ ccw_device_verify_irq(struct ccw_device
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;
@@ -441,6 +444,10 @@ ccw_device_verify_irq(struct ccw_device
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);
@@ -449,8 +456,7 @@ ccw_device_verify_irq(struct ccw_device
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;
@@ -463,19 +469,17 @@ ccw_device_verify_start(struct ccw_devic
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);
}

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