scsi: s390: zfcp: Ensure synchronous unit_add

commit 9697ca0d53e3db357be26d2414276143c4a2cd49 upstream.

Improve the usability of the unit_add sysfs attribute by ensuring that
the associated FCP LUN scan processing is completed synchronously.  This
enables configuration tooling to consistently determine the end of the
scan process to allow for serialization of follow-on actions.

While the scan process associated with unit_add typically completes
synchronously, it is deferred to an asynchronous background process if
unit_add is used before initial remote port scanning has completed.  This
occurs when unit_add is used immediately after setting the associated FCP
device online.

To ensure synchronous unit_add processing, wait for remote port scanning
to complete before initiating the FCP LUN scan.

Cc: stable@vger.kernel.org
Reviewed-by: M Nikhil <nikh1092@linux.ibm.com>
Reviewed-by: Nihar Panda <niharp@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Nihar Panda <niharp@linux.ibm.com>
Link: https://lore.kernel.org/r/20250603182252.2287285-2-niharp@linux.ibm.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/s390/scsi/zfcp_sysfs.c b/drivers/s390/scsi/zfcp_sysfs.c
index cb67fa80fb12c8cc8694b23f145006627383a9b3..a95da6768f665660a90de9923b4cc71d9bf47312 100644 (file)
--- a/drivers/s390/scsi/zfcp_sysfs.c
+++ b/drivers/s390/scsi/zfcp_sysfs.c
@@ -450,6 +450,8 @@ static ssize_t zfcp_sysfs_unit_add_store(struct device *dev,
        if (kstrtoull(buf, 0, (unsigned long long *) &fcp_lun))
                return -EINVAL;
 
+       flush_work(&port->rport_work);
+
        retval = zfcp_unit_add(port, fcp_lun);
        if (retval)
                return retval;