s390/scm_block: fix off by one during cluster reservation

We increase the msb_count after we're finished building the request.
That way we can always access the current request via
scmrq->request[msb_count] . But once the request is started we need
to make sure that the array index stays below msb_count.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/block/scm_blk_cluster.c b/drivers/s390/block/scm_blk_cluster.c
index 09db45296eed2c87330399abbfecdbb2f9b44014..7497ddde2dd67a28ce2e042970bebda9b3e9da5b 100644 (file)
--- a/drivers/s390/block/scm_blk_cluster.c
+++ b/drivers/s390/block/scm_blk_cluster.c
@@ -92,7 +92,7 @@ bool scm_reserve_cluster(struct scm_request *scmrq)
                        add = 0;
                        continue;
                }
-               for (pos = 0; pos <= iter->aob->request.msb_count; pos++) {
+               for (pos = 0; pos < iter->aob->request.msb_count; pos++) {
                        if (clusters_intersect(req, iter->request[pos]) &&
                            (rq_data_dir(req) == WRITE ||
                             rq_data_dir(iter->request[pos]) == WRITE)) {