[PATCH] staging: lustre: include linux/highmem.h when needed

[Arnd Bergmann <arnd@arndb.de>]

Something in recent linux-next kernels caused linux/highmem.h to
no longer be included implicitly from o2iblnd_cb.c, causing a build
failure:

drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c: In function 'kiblnd_kvaddr_to_page':
drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c:549:15: error: 'PKMAP_BASE' undeclared (first use in this function); did you mean 'RTM_BASE'?
  if (vaddr >= PKMAP_BASE &&
               ^~~~~~~~~~
               RTM_BASE
drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c:549:15: note: each undeclared identifier is reported only once for each function it appears in
drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c:550:28: error: 'LAST_PKMAP' undeclared (first use in this function); did you mean 'AT_HWCAP'?
      vaddr < (PKMAP_BASE + LAST_PKMAP * PAGE_SIZE)) {
                            ^~~~~~~~~~
                            AT_HWCAP

This adds back an explicit include for the header.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c
index 47eb8b4c28db..65b7a62943ad 100644
--- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c
+++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c
@@ -35,6 +35,7 @@
  * Author: Eric Barton <eric@bartonsoftware.com>
  */
 
+#include <linux/highmem.h>
 #include "o2iblnd.h"
 
 #define MAX_CONN_RACES_BEFORE_ABORT 20
-- 
2.9.0