[PATCH] s390: don't pad cdl blocks for write requests

The first blocks on a cdl formatted dasd device are smaller than the blocksize
of the device.  Read requests are padded with a 'e5' pattern.  Write requests
should not pad the (user) buffer with 'e5' because a write request is not
allowed to modify the buffer.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 838aedf78a56..811060e10c00 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -7,7 +7,7 @@
  * Bugreports.to..: <Linux390@de.ibm.com>
  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999,2000
  *
- * $Revision: 1.69 $
+ * $Revision: 1.71 $
  */
 
 #include <linux/config.h>
@@ -1101,7 +1101,8 @@ dasd_eckd_build_cp(struct dasd_device * device, struct request *req)
                                 if (dasd_eckd_cdl_special(blk_per_trk, recid)){
                                         rcmd |= 0x8;
                                         count = dasd_eckd_cdl_reclen(recid);
-                                        if (count < blksize)
+                                        if (count < blksize &&
+                                            rq_data_dir(req) == READ)
                                                 memset(dst + count, 0xe5,
                                                        blksize - count);
                                 }