partitions/ibm: fix non-DASD devices

Don't error out if the dasd_biodasdinfo symbol is not available.

Cc: stable@vger.kernel.org
Fixes: 26d7e28 ("s390/dasd: remove ioctl_by_bdev calls")
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/partitions/ibm.c

@@ -305,8 +305,6 @@ int ibm_partition(struct parsed_partitions *state)
 	if (!disk->fops->getgeo)
 		goto out_exit;
 	fn = symbol_get(dasd_biodasdinfo);
-	if (!fn)
-		goto out_exit;
 	blocksize = bdev_logical_block_size(bdev);
 	if (blocksize <= 0)
 		goto out_symbol;
@@ -326,7 +324,7 @@ int ibm_partition(struct parsed_partitions *state)
 	geo->start = get_start_sect(bdev);
 	if (disk->fops->getgeo(bdev, geo))
 		goto out_freeall;
-	if (fn(disk, info)) {
+	if (!fn || fn(disk, info)) {
 		kfree(info);
 		info = NULL;
 	}
@@ -370,7 +368,8 @@ int ibm_partition(struct parsed_partitions *state)
 out_nogeo:
 	kfree(info);
 out_symbol:
-	symbol_put(dasd_biodasdinfo);
+	if (fn)
+		symbol_put(dasd_biodasdinfo);
 out_exit:
 	return res;
 }