From: Horst Hummel <horst.hummel@de.ibm.com>
Date: Sun, 1 May 2005 15:58:59 +0000 (-0700)
Subject: [PATCH] s390: don't pad cdl blocks for write requests
X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~59621^2~104
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=ec5883abebb2e249ea8d318cb58fb4b2c269cf10;p=mirror_ubuntu-focal-kernel.git

[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>
---

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);
 				}