s390/dasd: fix failing CUIR assignment under LPAR

On LPAR the read message buffer command should be executed on the path
it was received on otherwise there is a chance that the CUIR assignment
might be faulty and the wrong channel path is set online/offline.

Fix by setting the path mask accordingly.
On z/VM we might not be able to do I/O on this path but there it does
not matter on which path the read message buffer command is executed.
Therefor implement a retry with an open path mask.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index fd2eff44009806c039ad18bd5d546d452c4d81fa..98bbec44bcd05c0c37da4d853c17e2c525767c3e 100644 (file)
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -5078,6 +5078,8 @@ static int dasd_eckd_read_message_buffer(struct dasd_device *device,
                return PTR_ERR(cqr);
        }
 
+       cqr->lpm = lpum;
+retry:
        cqr->startdev = device;
        cqr->memdev = device;
        cqr->block = NULL;
@@ -5122,6 +5124,14 @@ static int dasd_eckd_read_message_buffer(struct dasd_device *device,
                        (prssdp + 1);
                memcpy(messages, message_buf,
                       sizeof(struct dasd_rssd_messages));
+       } else if (cqr->lpm) {
+               /*
+                * on z/VM we might not be able to do I/O on the requested path
+                * but instead we get the required information on any path
+                * so retry with open path mask
+                */
+               cqr->lpm = 0;
+               goto retry;
        } else
                DBF_EVENT_DEVID(DBF_WARNING, device->cdev,
                                "Reading messages failed with rc=%d\n"