s390/dasd: fix pathgroup race
If a new path is available we need to verify the path data. If it is the
first path for a device the stop bits are removed after path verification.
If a pathgroup is established we need to set system characteristics for
the lcu. Therefore I/O has to be started.
If the device is stopped the set system characteristics worker may block
the path verification worker and the device is blocked.
Turn on failfast for set system characteristics CQR to prevent a deadlock
with the path verification worker.
If a pathgroup is established on a device that is not in use trigger path
verification. Maybe we were not informed about a working path.
Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Reviewed-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 2fb2b9e..c48c72a 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1507,7 +1507,8 @@
* call might change behaviour of DASD devices.
*/
static int
-dasd_eckd_psf_ssc(struct dasd_device *device, int enable_pav)
+dasd_eckd_psf_ssc(struct dasd_device *device, int enable_pav,
+ unsigned long flags)
{
struct dasd_ccw_req *cqr;
int rc;
@@ -1516,10 +1517,19 @@
if (IS_ERR(cqr))
return PTR_ERR(cqr);
+ /*
+ * set flags e.g. turn on failfast, to prevent blocking
+ * the calling function should handle failed requests
+ */
+ cqr->flags |= flags;
+
rc = dasd_sleep_on(cqr);
if (!rc)
/* trigger CIO to reprobe devices */
css_schedule_reprobe();
+ else if (cqr->intrc == -EAGAIN)
+ rc = -EAGAIN;
+
dasd_sfree_request(cqr, cqr->memdev);
return rc;
}
@@ -1527,7 +1537,8 @@
/*
* Valide storage server of current device.
*/
-static void dasd_eckd_validate_server(struct dasd_device *device)
+static int dasd_eckd_validate_server(struct dasd_device *device,
+ unsigned long flags)
{
int rc;
struct dasd_eckd_private *private;
@@ -1536,17 +1547,18 @@
private = (struct dasd_eckd_private *) device->private;
if (private->uid.type == UA_BASE_PAV_ALIAS ||
private->uid.type == UA_HYPER_PAV_ALIAS)
- return;
+ return 0;
if (dasd_nopav || MACHINE_IS_VM)
enable_pav = 0;
else
enable_pav = 1;
- rc = dasd_eckd_psf_ssc(device, enable_pav);
+ rc = dasd_eckd_psf_ssc(device, enable_pav, flags);
/* may be requested feature is not available on server,
* therefore just report error and go ahead */
DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "PSF-SSC for SSID %04x "
"returned rc=%d", private->uid.ssid, rc);
+ return rc;
}
/*
@@ -1556,7 +1568,13 @@
{
struct dasd_device *device = container_of(work, struct dasd_device,
kick_validate);
- dasd_eckd_validate_server(device);
+ if (dasd_eckd_validate_server(device, DASD_CQR_FLAGS_FAILFAST)
+ == -EAGAIN) {
+ /* schedule worker again if failed */
+ schedule_work(&device->kick_validate);
+ return;
+ }
+
dasd_put_device(device);
}
@@ -1685,7 +1703,7 @@
if (rc)
goto out_err2;
- dasd_eckd_validate_server(device);
+ dasd_eckd_validate_server(device, 0);
/* device may report different configuration data after LCU setup */
rc = dasd_eckd_read_conf(device);
@@ -4153,7 +4171,7 @@
rc = dasd_alias_make_device_known_to_lcu(device);
if (rc)
return rc;
- dasd_eckd_validate_server(device);
+ dasd_eckd_validate_server(device, DASD_CQR_FLAGS_FAILFAST);
/* RE-Read Configuration Data */
rc = dasd_eckd_read_conf(device);