[PATCH 3.18 27/68] drbd: avoid redefinition of BITS_PER_PAGE

Greg Kroah-Hartman
2017-05-05T18:51:40Z

From: Lars Ellenberg <lars.ellenberg@linbit.com>

commit 2630628b2dbc3fc320aafaf84836119e4e3d62f1 upstream.

Apparently we now implicitly get definitions for BITS_PER_PAGE and
BITS_PER_PAGE_MASK from the pid_namespace.h

Instead of renaming our defines, I chose to define only if not yet
defined, but to double check the value if already defined.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/block/drbd/drbd_bitmap.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -479,8 +479,14 @@ void drbd_bm_cleanup(struct drbd_device
* this masks out the remaining bits.
* Returns the number of bits cleared.
*/
+#ifndef BITS_PER_PAGE
#define BITS_PER_PAGE (1UL << (PAGE_SHIFT + 3))
#define BITS_PER_PAGE_MASK (BITS_PER_PAGE - 1)
+#else
+# if BITS_PER_PAGE != (1UL << (PAGE_SHIFT + 3))
+# error "ambiguous BITS_PER_PAGE"
+# endif
+#endif
#define BITS_PER_LONG_MASK (BITS_PER_LONG - 1)
static int bm_clear_surplus(struct drbd_bitmap *b)
{