Patch "drbd: avoid redefinition of BITS_PER_PAGE" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

drbd: avoid redefinition of BITS_PER_PAGE

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drbd-avoid-redefinition-of-bits_per_page.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Lars Ellenberg <[email protected]>
Date: Fri, 20 Mar 2015 15:47:22 +0100
Subject: drbd: avoid redefinition of BITS_PER_PAGE

From: Lars Ellenberg <[email protected]>

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.

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

@@ -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)
 {

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/drbd-avoid-redefinition-of-bits_per_page.patch