LU-14073 build: fix autoconf test for clean_bdev_aliases()

From 5.9, buffer_head.h no longer provides a declaration for
'struct block_device' so the code fragment fails because the compiler
doesn't know the size of that structure.

Instead, simple pass NULL rather than the address of a real structure.

Test-Parameters: trivial
Signed-off-by: Mr NeilBrown <neilb@suse.de>
Change-Id: I1775572fbd56d22822b6e440fe95bd105042e7b8
Reviewed-on: https://review.whamcloud.com/40395
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Aurelien Degremont <degremoa@amazon.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>

diff --git a/lustre/autoconf/lustre-core.m4 b/lustre/autoconf/lustre-core.m4
index 58494f4..6143d96 100644 (file)
--- a/lustre/autoconf/lustre-core.m4
+++ b/lustre/autoconf/lustre-core.m4
@@ -1287,8 +1287,7 @@ LB_CHECK_COMPILE([if kernel has clean_bdev_aliases],
 have_clean_bdev_aliases, [
        #include <linux/buffer_head.h>
 ],[
-       struct block_device bdev;
-       clean_bdev_aliases(&bdev,1,1);
+       clean_bdev_aliases(NULL,1,1);
 ], [
        AC_DEFINE(HAVE_CLEAN_BDEV_ALIASES, 1,
                [kernel has clean_bdev_aliases])