[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>
diff --git a/drivers/s390/cio/device_pgid.c b/drivers/s390/cio/device_pgid.c
index 1693a10..8ca2d07 100644
--- a/drivers/s390/cio/device_pgid.c
+++ b/drivers/s390/cio/device_pgid.c
@@ -245,18 +245,17 @@
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 @@
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 @@
__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 @@
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 @@
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_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 @@
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 @@
switch (ret) {
/* 0, -ETIME, -EAGAIN, -EOPNOTSUPP or -EACCES */
case 0: /* disband successful. */
- sch->vpm = 0;
ccw_device_disband_done(cdev, ret);
break;
case -EOPNOTSUPP: