[patch 43/52] [PATCH] cio: make steal lock procedure more robust

Martin Schwidefsky
2009-11-13T15:10:50Z

[-- Attachment #1: 142-cio-steal-lock.diff --]
[-- Type: text/plain, Size: 9954 bytes --]

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

An Unconditional Reserve + Release operation (steal lock) for a
boxed device may fail when encountering special error cases
(e.g. unit checks or path errors). Fix this by using the more
robust ccw_request infrastructure for performing the steal lock
CCW program.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

drivers/s390/cio/device.h | 4 +
drivers/s390/cio/device_fsm.c | 55 +++++++++-----------
drivers/s390/cio/device_ops.c | 112 +++++++++++++++++++----------------------
drivers/s390/cio/device_pgid.c | 52 +++++++++++++++++++
4 files changed, 134 insertions(+), 89 deletions(-)

Index: quilt-2.6/drivers/s390/cio/device_fsm.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device_fsm.c 2009-11-13 16:08:21.000000000 +0100
+++ quilt-2.6/drivers/s390/cio/device_fsm.c 2009-11-13 16:08:21.000000000 +0100
@@ -641,6 +641,23 @@
}

/*
+ * Handle path verification event in boxed state.
+ */
+static void ccw_device_boxed_verify(struct ccw_device *cdev,
+ enum dev_event dev_event)
+{
+ struct subchannel *sch = to_subchannel(cdev->dev.parent);
+
+ if (cdev->online) {
+ if (cio_enable_subchannel(sch, (u32) (addr_t) sch))
+ ccw_device_done(cdev, DEV_STATE_NOT_OPER);
+ else
+ ccw_device_online_verify(cdev, dev_event);
+ } else
+ css_schedule_eval(sch->schid);
+}
+
+/*
* Got an interrupt for a normal io (state online).
*/
static void
@@ -817,32 +834,6 @@
}

static void
-ccw_device_stlck_done(struct ccw_device *cdev, enum dev_event dev_event)
-{
- struct irb *irb;
-
- switch (dev_event) {
- case DEV_EVENT_INTERRUPT:
- irb = (struct irb *) __LC_IRB;
- /* Check for unsolicited interrupt. */
- if ((scsw_stctl(&irb->scsw) ==
- (SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) &&
- (!scsw_cc(&irb->scsw)))
- /* FIXME: we should restart stlck here, but this
- * is extremely unlikely ... */
- goto out_wakeup;
-
- ccw_device_accumulate_irb(cdev, irb);
- /* We don't care about basic sense etc. */
- break;
- default: /* timeout */
- break;
- }
-out_wakeup:
- wake_up(&cdev->private->wait_q);
-}
-
-static void
ccw_device_start_id(struct ccw_device *cdev, enum dev_event dev_event)
{
struct subchannel *sch;
@@ -1010,9 +1001,9 @@
},
[DEV_STATE_BOXED] = {
[DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
- [DEV_EVENT_INTERRUPT] = ccw_device_stlck_done,
- [DEV_EVENT_TIMEOUT] = ccw_device_stlck_done,
- [DEV_EVENT_VERIFY] = ccw_device_nop,
+ [DEV_EVENT_INTERRUPT] = ccw_device_nop,
+ [DEV_EVENT_TIMEOUT] = ccw_device_nop,
+ [DEV_EVENT_VERIFY] = ccw_device_boxed_verify,
},
/* states to wait for i/o completion before doing something */
[DEV_STATE_TIMEOUT_KILL] = {
@@ -1052,6 +1043,12 @@
[DEV_EVENT_TIMEOUT] = ccw_device_update_cmfblock,
[DEV_EVENT_VERIFY] = ccw_device_update_cmfblock,
},
+ [DEV_STATE_STEAL_LOCK] = {
+ [DEV_EVENT_NOTOPER] = ccw_device_request_event,
+ [DEV_EVENT_INTERRUPT] = ccw_device_request_event,
+ [DEV_EVENT_TIMEOUT] = ccw_device_request_event,
+ [DEV_EVENT_VERIFY] = ccw_device_nop,
+ },
};

EXPORT_SYMBOL_GPL(ccw_device_set_timeout);
Index: quilt-2.6/drivers/s390/cio/device.h
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device.h 2009-11-13 16:08:21.000000000 +0100
+++ quilt-2.6/drivers/s390/cio/device.h 2009-11-13 16:08:21.000000000 +0100
@@ -28,6 +28,7 @@
DEV_STATE_DISCONNECTED_SENSE_ID,
DEV_STATE_CMFCHANGE,
DEV_STATE_CMFUPDATE,
+ DEV_STATE_STEAL_LOCK,
/* last element! */
NR_DEV_STATES
};
@@ -116,6 +117,9 @@
void ccw_device_disband_start(struct ccw_device *);
void ccw_device_disband_done(struct ccw_device *, int);

+void ccw_device_stlck_start(struct ccw_device *, void *, void *, void *);
+void ccw_device_stlck_done(struct ccw_device *, void *, int);
+
int ccw_device_call_handler(struct ccw_device *);

int ccw_device_stlck(struct ccw_device *);
Index: quilt-2.6/drivers/s390/cio/device_ops.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device_ops.c 2009-11-13 16:08:21.000000000 +0100
+++ quilt-2.6/drivers/s390/cio/device_ops.c 2009-11-13 16:08:21.000000000 +0100
@@ -11,6 +11,7 @@
#include <linux/list.h>
#include <linux/device.h>
#include <linux/delay.h>
+#include <linux/completion.h>

#include <asm/ccwdev.h>
#include <asm/idals.h>
@@ -504,74 +505,65 @@
return sch->lpm;
}

-/*
- * Try to break the lock on a boxed device.
- */
-int
-ccw_device_stlck(struct ccw_device *cdev)
-{
- void *buf, *buf2;
- unsigned long flags;
- struct subchannel *sch;
- int ret;
+struct stlck_data {
+ struct completion done;
+ int rc;
+};

- if (!cdev)
- return -ENODEV;
+void ccw_device_stlck_done(struct ccw_device *cdev, void *data, int rc)
+{
+ struct stlck_data *sdata = data;

- if (cdev->drv && !cdev->private->options.force)
- return -EINVAL;
+ sdata->rc = rc;
+ complete(&sdata->done);
+}

- sch = to_subchannel(cdev->dev.parent);
-
- CIO_TRACE_EVENT(2, "stl lock");
- CIO_TRACE_EVENT(2, dev_name(&cdev->dev));
+/*
+ * Perform unconditional reserve + release.
+ */
+int ccw_device_stlck(struct ccw_device *cdev)
+{
+ struct subchannel *sch = to_subchannel(cdev->dev.parent);
+ struct stlck_data data;
+ u8 *buffer;
+ int rc;

- buf = kmalloc(32*sizeof(char), GFP_DMA|GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
- buf2 = kmalloc(32*sizeof(char), GFP_DMA|GFP_KERNEL);
- if (!buf2) {
- kfree(buf);
- return -ENOMEM;
+ /* Check if steal lock operation is valid for this device. */
+ if (cdev->drv) {
+ if (!cdev->private->options.force)
+ return -EINVAL;
}
- spin_lock_irqsave(sch->lock, flags);
- ret = cio_enable_subchannel(sch, (u32)(addr_t)sch);
- if (ret)
- goto out_unlock;
- /*
- * Setup ccw. We chain an unconditional reserve and a release so we
- * only break the lock.
- */
- cdev->private->iccws[0].cmd_code = CCW_CMD_STLCK;
- cdev->private->iccws[0].cda = (__u32) __pa(buf);
- cdev->private->iccws[0].count = 32;
- cdev->private->iccws[0].flags = CCW_FLAG_CC;
- cdev->private->iccws[1].cmd_code = CCW_CMD_RELEASE;
- cdev->private->iccws[1].cda = (__u32) __pa(buf2);
- cdev->private->iccws[1].count = 32;
- cdev->private->iccws[1].flags = 0;
- ret = cio_start(sch, cdev->private->iccws, 0);
- if (ret) {
- cio_disable_subchannel(sch); //FIXME: return code?
+ buffer = kzalloc(64, GFP_DMA | GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
+ init_completion(&data.done);
+ data.rc = -EIO;
+ spin_lock_irq(sch->lock);
+ rc = cio_enable_subchannel(sch, (u32) (addr_t) sch);
+ if (rc)
goto out_unlock;
+ /* Perform operation. */
+ cdev->private->state = DEV_STATE_STEAL_LOCK,
+ ccw_device_stlck_start(cdev, &data, &buffer[0], &buffer[32]);
+ spin_unlock_irq(sch->lock);
+ /* Wait for operation to finish. */
+ if (wait_for_completion_interruptible(&data.done)) {
+ /* Got a signal. */
+ spin_lock_irq(sch->lock);
+ ccw_request_cancel(cdev);
+ spin_unlock_irq(sch->lock);
+ wait_for_completion(&data.done);
}
- cdev->private->irb.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
- spin_unlock_irqrestore(sch->lock, flags);
- wait_event(cdev->private->wait_q,
- cdev->private->irb.scsw.cmd.actl == 0);
- spin_lock_irqsave(sch->lock, flags);
- cio_disable_subchannel(sch); //FIXME: return code?
- if ((cdev->private->irb.scsw.cmd.dstat !=
- (DEV_STAT_CHN_END|DEV_STAT_DEV_END)) ||
- (cdev->private->irb.scsw.cmd.cstat != 0))
- ret = -EIO;
- /* Clear irb. */
- memset(&cdev->private->irb, 0, sizeof(struct irb));
+ rc = data.rc;
+ /* Check results. */
+ spin_lock_irq(sch->lock);
+ cio_disable_subchannel(sch);
+ cdev->private->state = DEV_STATE_BOXED;
out_unlock:
- kfree(buf);
- kfree(buf2);
- spin_unlock_irqrestore(sch->lock, flags);
- return ret;
+ spin_unlock_irq(sch->lock);
+ kfree(buffer);
+
+ return rc;
}

void *ccw_device_get_chp_desc(struct ccw_device *cdev, int chp_no)
Index: quilt-2.6/drivers/s390/cio/device_pgid.c
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/device_pgid.c 2009-11-13 16:08:21.000000000 +0100
+++ quilt-2.6/drivers/s390/cio/device_pgid.c 2009-11-13 16:08:21.000000000 +0100
@@ -507,3 +507,55 @@
spid_build_cp(cdev, fn);
ccw_request_start(cdev);
}
+
+static void stlck_build_cp(struct ccw_device *cdev, void *buf1, void *buf2)
+{
+ struct ccw_request *req = &cdev->private->req;
+ struct ccw1 *cp = cdev->private->iccws;
+
+ cp[0].cmd_code = CCW_CMD_STLCK;
+ cp[0].cda = (u32) (addr_t) buf1;
+ cp[0].count = 32;
+ cp[0].flags = CCW_FLAG_CC;
+ cp[1].cmd_code = CCW_CMD_RELEASE;
+ cp[1].cda = (u32) (addr_t) buf2;
+ cp[1].count = 32;
+ cp[1].flags = 0;
+ req->cp = cp;
+}
+
+static void stlck_callback(struct ccw_device *cdev, void *data, int rc)
+{
+ ccw_device_stlck_done(cdev, data, rc);
+}
+
+/**
+ * ccw_device_stlck_start - perform unconditional release
+ * @cdev: ccw device
+ * @data: data pointer to be passed to ccw_device_stlck_done
+ * @buf1: data pointer used in channel program
+ * @buf2: data pointer used in channel program
+ *
+ * Execute a channel program on @cdev to release an existing PGID reservation.
+ * When finished, call ccw_device_stlck_done with a return code specifying the
+ * result.
+ */
+void ccw_device_stlck_start(struct ccw_device *cdev, void *data, void *buf1,
+ void *buf2)
+{
+ struct subchannel *sch = to_subchannel(cdev->dev.parent);
+ struct ccw_request *req = &cdev->private->req;
+
+ CIO_TRACE_EVENT(4, "stlck");
+ CIO_HEX_EVENT(4, &cdev->private->dev_id, sizeof(cdev->private->dev_id));
+ /* Request setup. */
+ memset(req, 0, sizeof(*req));
+ req->timeout = PGID_TIMEOUT;
+ req->maxretries = PGID_RETRIES;
+ req->lpm = sch->schib.pmcw.pam & sch->opm;
+ req->data = data;
+ req->callback = stlck_callback;
+ stlck_build_cp(cdev, buf1, buf2);
+ ccw_request_start(cdev);
+}
+