s390/dasd: retry partition detection

In case somebody attempted to open the device during online
processing the partition detection ioctl may have failed.

Added a retry loop to avoid not detected partitions.

Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index f224d59c4b6be35b8a5d827dde6cdc173953f3f5..90f39f79f5d75ae2ad1700223adb519e101abd33 100644 (file)
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -99,15 +99,37 @@ void dasd_gendisk_free(struct dasd_block *block)
 int dasd_scan_partitions(struct dasd_block *block)
 {
        struct block_device *bdev;
+       int retry, rc;
 
+       retry = 5;
        bdev = bdget_disk(block->gdp, 0);
-       if (!bdev || blkdev_get(bdev, FMODE_READ, NULL) < 0)
+       if (!bdev) {
+               DBF_DEV_EVENT(DBF_ERR, block->base, "%s",
+                             "scan partitions error, bdget returned NULL");
                return -ENODEV;
+       }
+
+       rc = blkdev_get(bdev, FMODE_READ, NULL);
+       if (rc < 0) {
+               DBF_DEV_EVENT(DBF_ERR, block->base,
+                             "scan partitions error, blkdev_get returned %d",
+                             rc);
+               return -ENODEV;
+       }
        /*
         * See fs/partition/check.c:register_disk,rescan_partitions
         * Can't call rescan_partitions directly. Use ioctl.
         */
-       ioctl_by_bdev(bdev, BLKRRPART, 0);
+       rc = ioctl_by_bdev(bdev, BLKRRPART, 0);
+       while (rc == -EBUSY && retry > 0) {
+               schedule();
+               rc = ioctl_by_bdev(bdev, BLKRRPART, 0);
+               retry--;
+               DBF_DEV_EVENT(DBF_ERR, block->base,
+                             "scan partitions error, retry %d rc %d",
+                             retry, rc);
+       }
+
        /*
         * Since the matching blkdev_put call to the blkdev_get in
         * this function is not called before dasd_destroy_partitions