[SCSI] scsi_dh: fix kconfig related build errors

Do not automatically "select" SCSI_DH for dm-multipath. If SCSI_DH
doesn't exist,just do not allow  hardware handlers to be used.

Handle SCSI_DH being a module also. Make sure it doesn't allow DM_MULTIPATH
to be compiled in when SCSI_DH is a module.

[jejb: added comment for Kconfig syntax]
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index b4a3c7d1451..07d92c11b5d 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -252,7 +252,11 @@ config DM_ZERO
 config DM_MULTIPATH
         tristate "Multipath target"
         depends on BLK_DEV_DM
-        select SCSI_DH
+        # nasty syntax but means make DM_MULTIPATH independent
+        # of SCSI_DH if the latter isn't defined but if
+        # it is, DM_MULTIPATH must depend on it.  We get a build
+        # error if SCSI_DH=m and DM_MULTIPATH=y
+        depends on SCSI_DH || !SCSI_DH
         ---help---
           Allow volume managers to support multipath hardware.