[PATCH v4 01/16] s390: cio: introduce cio_cancel_halt_clear

Dong Jia Shi
2017-03-17T04:06:46Z

For future code reuse purpose, this decouples the cio code with
the ccw device specific parts from ccw_device_cancel_halt_clear,
and makes a new common I/O interface named cio_cancel_halt_clear.

Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
---
drivers/s390/cio/cio.c | 59 +++++++++++++++++++++++++++++++++++++++++++
drivers/s390/cio/cio.h | 1 +
drivers/s390/cio/device_fsm.c | 54 ++++++---------------------------------
3 files changed, 68 insertions(+), 46 deletions(-)

diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index 1b35066..5711e28 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -309,6 +309,65 @@ cio_cancel (struct subchannel *sch)
}
}

+/**
+ * cio_cancel_halt_clear - Cancel running I/O by performing cancel, halt
+ * and clear ordinally if subchannel is valid.
+ * @sch: subchannel on which to perform the cancel_halt_clear operation
+ * @iretry: the number of the times remained to retry the next operation
+ *
+ * This should be called repeatedly since halt/clear are asynchronous
+ * operations. We do one try with cio_cancel, two tries with cio_halt,
+ * 255 tries with cio_clear. The caller should initialize @iretry with
+ * the value 255 for its first call to this, and keep using the same
+ * @iretry in the subsequent calls until it gets a non -EBUSY return.
+ *
+ * Returns 0 if device now idle, -ENODEV for device not operational,
+ * -EBUSY if an interrupt is expected (either from halt/clear or from a
+ * status pending), and -EIO if out of retries.
+ */
+int cio_cancel_halt_clear(struct subchannel *sch, int *iretry)
+{
+ int ret;
+
+ if (cio_update_schib(sch))
+ return -ENODEV;
+ if (!sch->schib.pmcw.ena)
+ /* Not operational -> done. */
+ return 0;
+ /* Stage 1: cancel io. */
+ if (!(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_HALT_PEND) &&
+ !(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_CLEAR_PEND)) {
+ if (!scsw_is_tm(&sch->schib.scsw)) {
+ ret = cio_cancel(sch);
+ if (ret != -EINVAL)
+ return ret;
+ }
+ /*
+ * Cancel io unsuccessful or not applicable (transport mode).
+ * Continue with asynchronous instructions.
+ */
+ *iretry = 3; /* 3 halt retries. */
+ }
+ /* Stage 2: halt io. */
+ if (!(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_CLEAR_PEND)) {
+ if (*iretry) {
+ *iretry -= 1;
+ ret = cio_halt(sch);
+ if (ret != -EBUSY)
+ return (ret == 0) ? -EBUSY : ret;
+ }
+ /* Halt io unsuccessful. */
+ *iretry = 255; /* 255 clear retries. */
+ }
+ /* Stage 3: clear io. */
+ if (*iretry) {
+ *iretry -= 1;
+ ret = cio_clear(sch);
+ return (ret == 0) ? -EBUSY : ret;
+ }
+ /* Function was unsuccessful */
+ return -EIO;
+}

static void cio_apply_config(struct subchannel *sch, struct schib *schib)
{
diff --git a/drivers/s390/cio/cio.h b/drivers/s390/cio/cio.h
index f0e57ae..939596d 100644
--- a/drivers/s390/cio/cio.h
+++ b/drivers/s390/cio/cio.h
@@ -123,6 +123,7 @@ extern int cio_enable_subchannel(struct subchannel *, u32);
extern int cio_disable_subchannel (struct subchannel *);
extern int cio_cancel (struct subchannel *);
extern int cio_clear (struct subchannel *);
+extern int cio_cancel_halt_clear(struct subchannel *, int *);
extern int cio_resume (struct subchannel *);
extern int cio_halt (struct subchannel *);
extern int cio_start (struct subchannel *, struct ccw1 *, __u8);
diff --git a/drivers/s390/cio/device_fsm.c b/drivers/s390/cio/device_fsm.c
index 9afb5ce..12016e3 100644
--- a/drivers/s390/cio/device_fsm.c
+++ b/drivers/s390/cio/device_fsm.c
@@ -124,14 +124,6 @@ ccw_device_set_timeout(struct ccw_device *cdev, int expires)
add_timer(&cdev->private->timer);
}

-/*
- * Cancel running i/o. This is called repeatedly since halt/clear are
- * asynchronous operations. We do one try with cio_cancel, two tries
- * with cio_halt, 255 tries with cio_clear. If everythings fails panic.
- * Returns 0 if device now idle, -ENODEV for device not operational and
- * -EBUSY if an interrupt is expected (either from halt/clear or from a
- * status pending).
- */
int
ccw_device_cancel_halt_clear(struct ccw_device *cdev)
{
@@ -139,44 +131,14 @@ ccw_device_cancel_halt_clear(struct ccw_device *cdev)
int ret;

sch = to_subchannel(cdev->dev.parent);
- if (cio_update_schib(sch))
- return -ENODEV;
- if (!sch->schib.pmcw.ena)
- /* Not operational -> done. */
- return 0;
- /* Stage 1: cancel io. */
- if (!(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_HALT_PEND) &&
- !(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_CLEAR_PEND)) {
- if (!scsw_is_tm(&sch->schib.scsw)) {
- ret = cio_cancel(sch);
- if (ret != -EINVAL)
- return ret;
- }
- /* cancel io unsuccessful or not applicable (transport mode).
- * Continue with asynchronous instructions. */
- cdev->private->iretry = 3; /* 3 halt retries. */
- }
- if (!(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_CLEAR_PEND)) {
- /* Stage 2: halt io. */
- if (cdev->private->iretry) {
- cdev->private->iretry--;
- ret = cio_halt(sch);
- if (ret != -EBUSY)
- return (ret == 0) ? -EBUSY : ret;
- }
- /* halt io unsuccessful. */
- cdev->private->iretry = 255; /* 255 clear retries. */
- }
- /* Stage 3: clear io. */
- if (cdev->private->iretry) {
- cdev->private->iretry--;
- ret = cio_clear (sch);
- return (ret == 0) ? -EBUSY : ret;
- }
- /* Function was unsuccessful */
- CIO_MSG_EVENT(0, "0.%x.%04x: could not stop I/O\n",
- cdev->private->dev_id.ssid, cdev->private->dev_id.devno);
- return -EIO;
+ ret = cio_cancel_halt_clear(sch, &cdev->private->iretry);
+
+ if (ret == -EIO)
+ CIO_MSG_EVENT(0, "0.%x.%04x: could not stop I/O\n",
+ cdev->private->dev_id.ssid,
+ cdev->private->dev_id.devno);
+
+ return ret;
}

void ccw_device_update_sense_data(struct ccw_device *cdev)
--
2.8.4