s390/dasd: add missing discipline function

Fix crash with illegal operation exception in dasd_device_tasklet.
Commit b7294932 ("s390/dasd: Prepare for additional path event handling")
renamed the verify_path function for ECKD but not for FBA and DIAG.
This leads to a panic when the path verification function is called for a
FBA or DIAG device.

Fix by defining a wrapper function for dasd_generic_verify_path().

Fixes: b7294932 ("s390/dasd: Prepare for additional path event handling")
Cc: <stable@vger.kernel.org> #5.11
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Link: https://lore.kernel.org/r/20210525125006.157531-2-sth@linux.ibm.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/s390/block/dasd_diag.c

@@ -642,12 +642,18 @@ static void dasd_diag_setup_blk_queue(struct dasd_block *block)
 	blk_queue_segment_boundary(q, PAGE_SIZE - 1);
 }
 
+static int dasd_diag_pe_handler(struct dasd_device *device,
+				__u8 tbvpm, __u8 fcsecpm)
+{
+	return dasd_generic_verify_path(device, tbvpm);
+}
+
 static struct dasd_discipline dasd_diag_discipline = {
 	.owner = THIS_MODULE,
 	.name = "DIAG",
 	.ebcname = "DIAG",
 	.check_device = dasd_diag_check_device,
-	.verify_path = dasd_generic_verify_path,
+	.pe_handler = dasd_diag_pe_handler,
 	.fill_geometry = dasd_diag_fill_geometry,
 	.setup_blk_queue = dasd_diag_setup_blk_queue,
 	.start_IO = dasd_start_diag,

drivers/s390/block/dasd_fba.c

@@ -794,13 +794,19 @@ static void dasd_fba_setup_blk_queue(struct dasd_block *block)
 	blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
 }
 
+static int dasd_fba_pe_handler(struct dasd_device *device,
+			       __u8 tbvpm, __u8 fcsecpm)
+{
+	return dasd_generic_verify_path(device, tbvpm);
+}
+
 static struct dasd_discipline dasd_fba_discipline = {
 	.owner = THIS_MODULE,
 	.name = "FBA ",
 	.ebcname = "FBA ",
 	.check_device = dasd_fba_check_characteristics,
 	.do_analysis = dasd_fba_do_analysis,
-	.verify_path = dasd_generic_verify_path,
+	.pe_handler = dasd_fba_pe_handler,
 	.setup_blk_queue = dasd_fba_setup_blk_queue,
 	.fill_geometry = dasd_fba_fill_geometry,
 	.start_IO = dasd_start_IO,

drivers/s390/block/dasd_int.h

@@ -297,7 +297,6 @@ struct dasd_discipline {
 	 * e.g. verify that new path is compatible with the current
 	 * configuration.
 	 */
-	int (*verify_path)(struct dasd_device *, __u8);
 	int (*pe_handler)(struct dasd_device *, __u8, __u8);
 
 	/*