[S390] cio: make steal lock procedure more robust

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>

1 files changed, 52 insertions, 60 deletions

diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c
index d4be16acebe..6da84543dfe 100644
--- a/drivers/s390/cio/device_ops.c
+++ b/drivers/s390/cio/device_ops.c
@@ -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 @@ __u8 ccw_device_get_path_mask(struct ccw_device *cdev)
         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)