[S390] dasd: fix race between tasklet and dasd_sleep_on

[sfrench/cifs-2.6.git] / drivers / s390 / block / dasd.c

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 4951aa82e9f5c30fd676d3978900f09924588322..fa2339cb1681f43fb19e337ad037f75d908b8d89 100644 (file)
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -26,6 +26,7 @@
 #include <asm/ebcdic.h>
 #include <asm/idals.h>
 #include <asm/itcw.h>
+#include <asm/diag.h>
 
 /* This is ugly... */
 #define PRINTK_HEADER "dasd:"
@@ -36,6 +37,9 @@
  */
 #define DASD_CHANQ_MAX_SIZE 4
 
+#define DASD_SLEEPON_START_TAG (void *) 1
+#define DASD_SLEEPON_END_TAG   (void *) 2
+
 /*
  * SECTION: exported variables of dasd.c
  */
@@ -1471,7 +1475,10 @@ void dasd_add_request_tail(struct dasd_ccw_req *cqr)
  */
 static void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
 {
-       wake_up((wait_queue_head_t *) data);
+       spin_lock_irq(get_ccwdev_lock(cqr->startdev->cdev));
+       cqr->callback_data = DASD_SLEEPON_END_TAG;
+       spin_unlock_irq(get_ccwdev_lock(cqr->startdev->cdev));
+       wake_up(&generic_waitq);
 }
 
 static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
@@ -1481,10 +1488,7 @@ static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
 
        device = cqr->startdev;
        spin_lock_irq(get_ccwdev_lock(device->cdev));
-       rc = ((cqr->status == DASD_CQR_DONE ||
-              cqr->status == DASD_CQR_NEED_ERP ||
-              cqr->status == DASD_CQR_TERMINATED) &&
-             list_empty(&cqr->devlist));
+       rc = (cqr->callback_data == DASD_SLEEPON_END_TAG);
        spin_unlock_irq(get_ccwdev_lock(device->cdev));
        return rc;
 }
@@ -1572,7 +1576,7 @@ static int _dasd_sleep_on(struct dasd_ccw_req *maincqr, int interruptible)
                        wait_event(generic_waitq, !(device->stopped));
 
                cqr->callback = dasd_wakeup_cb;
-               cqr->callback_data = (void *) &generic_waitq;
+               cqr->callback_data = DASD_SLEEPON_START_TAG;
                dasd_add_request_tail(cqr);
                if (interruptible) {
                        rc = wait_event_interruptible(
@@ -1651,7 +1655,7 @@ int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)
        }
 
        cqr->callback = dasd_wakeup_cb;
-       cqr->callback_data = (void *) &generic_waitq;
+       cqr->callback_data = DASD_SLEEPON_START_TAG;
        cqr->status = DASD_CQR_QUEUED;
        list_add(&cqr->devlist, &device->ccw_queue);
 
@@ -1898,7 +1902,8 @@ restart:
                /*  Process requests that may be recovered */
                if (cqr->status == DASD_CQR_NEED_ERP) {
                        erp_fn = base->discipline->erp_action(cqr);
-                       erp_fn(cqr);
+                       if (IS_ERR(erp_fn(cqr)))
+                               continue;
                        goto restart;
                }
 
@@ -2212,6 +2217,13 @@ static int dasd_open(struct block_device *bdev, fmode_t mode)
                goto out;
        }
 
+       if ((mode & FMODE_WRITE) &&
+           (test_bit(DASD_FLAG_DEVICE_RO, &base->flags) ||
+            (base->features & DASD_FEATURE_READONLY))) {
+               rc = -EROFS;
+               goto out;
+       }
+
        return 0;
 
 out:
@@ -2289,6 +2301,34 @@ dasd_exit(void)
  * SECTION: common functions for ccw_driver use
  */
 
+/*
+ * Is the device read-only?
+ * Note that this function does not report the setting of the
+ * readonly device attribute, but how it is configured in z/VM.
+ */
+int dasd_device_is_ro(struct dasd_device *device)
+{
+       struct ccw_dev_id dev_id;
+       struct diag210 diag_data;
+       int rc;
+
+       if (!MACHINE_IS_VM)
+               return 0;
+       ccw_device_get_id(device->cdev, &dev_id);
+       memset(&diag_data, 0, sizeof(diag_data));
+       diag_data.vrdcdvno = dev_id.devno;
+       diag_data.vrdclen = sizeof(diag_data);
+       rc = diag210(&diag_data);
+       if (rc == 0 || rc == 2) {
+               return diag_data.vrdcvfla & 0x80;
+       } else {
+               DBF_EVENT(DBF_WARNING, "diag210 failed for dev=%04x with rc=%d",
+                         dev_id.devno, rc);
+               return 0;
+       }
+}
+EXPORT_SYMBOL_GPL(dasd_device_is_ro);
+
 static void dasd_generic_auto_online(void *data, async_cookie_t cookie)
 {
        struct ccw_device *cdev = data;