[PATCH] s390: dasd failfast support
To properly support multipath-failover handling, the linux block layer has
introduced a special request flag, 'REQ_FAILFAST'. This flag is now used to
return requests immediately in case the device is not operational.
Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 6278739..1141a59 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -7,7 +7,7 @@
* Bugreports.to..: <Linux390@de.ibm.com>
* (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
*
- * $Revision: 1.169 $
+ * $Revision: 1.172 $
*/
#include <linux/config.h>
@@ -1224,6 +1224,12 @@
if (list_empty(&device->ccw_queue))
return;
cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, list);
+ /* check FAILFAST */
+ if (device->stopped & ~DASD_STOPPED_PENDING &&
+ test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags)) {
+ cqr->status = DASD_CQR_FAILED;
+ dasd_schedule_bh(device);
+ }
if ((cqr->status == DASD_CQR_QUEUED) &&
(!device->stopped)) {
/* try to start the first I/O that can be started */
@@ -1750,8 +1756,10 @@
* SECTION: common functions for ccw_driver use
*/
-/* initial attempt at a probe function. this can be simplified once
- * the other detection code is gone */
+/*
+ * Initial attempt at a probe function. this can be simplified once
+ * the other detection code is gone.
+ */
int
dasd_generic_probe (struct ccw_device *cdev,
struct dasd_discipline *discipline)
@@ -1770,8 +1778,10 @@
return ret;
}
-/* this will one day be called from a global not_oper handler.
- * It is also used by driver_unregister during module unload */
+/*
+ * This will one day be called from a global not_oper handler.
+ * It is also used by driver_unregister during module unload.
+ */
void
dasd_generic_remove (struct ccw_device *cdev)
{
@@ -1798,9 +1808,11 @@
dasd_delete_device(device);
}
-/* activate a device. This is called from dasd_{eckd,fba}_probe() when either
+/*
+ * Activate a device. This is called from dasd_{eckd,fba}_probe() when either
* the device is detected for the first time and is supposed to be used
- * or the user has started activation through sysfs */
+ * or the user has started activation through sysfs.
+ */
int
dasd_generic_set_online (struct ccw_device *cdev,
struct dasd_discipline *discipline)
@@ -1917,7 +1929,6 @@
if (cqr->status == DASD_CQR_IN_IO)
cqr->status = DASD_CQR_FAILED;
device->stopped |= DASD_STOPPED_DC_EIO;
- dasd_schedule_bh(device);
} else {
list_for_each_entry(cqr, &device->ccw_queue, list)
if (cqr->status == DASD_CQR_IN_IO) {
@@ -1927,6 +1938,7 @@
device->stopped |= DASD_STOPPED_DC_WAIT;
dasd_set_timer(device, 0);
}
+ dasd_schedule_bh(device);
ret = 1;
break;
case CIO_OPER: