[S390] dasd: fix idaw boundary checking for track based ccw

A ccw command that reads or writes several records at once will
usually transfer more data then fits into one page and needs to
address memory areas using a list of indirect data address words
(idaw). All but the first of these areas must start on a 4KB or 2KB
block boundary (depending on the idaw format).
A check for this restriction was missing and has been added with
this patch.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 2125479..cb52da0 100644 (file)
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -2019,15 +2019,23 @@ static struct dasd_ccw_req *dasd_eckd_build_cp_cmd_track(
                                ccw++;
                                recid += count;
                                new_track = 0;
+                               /* first idaw for a ccw may start anywhere */
+                               if (!idaw_dst)
+                                       idaw_dst = dst;
                        }
-                       /* If we start a new idaw, everything is fine and the
-                        * start of the new idaw is the start of this segment.
+                       /* If we start a new idaw, we must make sure that it
+                        * starts on an IDA_BLOCK_SIZE boundary.
                         * If we continue an idaw, we must make sure that the
                         * current segment begins where the so far accumulated
                         * idaw ends
                         */
-                       if (!idaw_dst)
-                               idaw_dst = dst;
+                       if (!idaw_dst) {
+                               if (__pa(dst) & (IDA_BLOCK_SIZE-1)) {
+                                       dasd_sfree_request(cqr, startdev);
+                                       return ERR_PTR(-ERANGE);
+                               } else
+                                       idaw_dst = dst;
+                       }
                        if ((idaw_dst + idaw_len) != dst) {
                                dasd_sfree_request(cqr, startdev);
                                return ERR_PTR(-ERANGE);