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

[Dong Jia Shi]

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 <address@hidden>
Signed-off-by: Dong Jia Shi <address@hidden>
Cc: Sebastian Ott <address@hidden>
Cc: Peter Oberparleiter <address@hidden>
---
 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