Patch "drbd: avoid redefinition of BITS_PER_PAGE" has been added to the 3.18-stable tree

Patch "drbd: avoid redefinition of BITS_PER_PAGE" has been added to the 3.18-stable tree

[gregkh]

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 3.18-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-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 2630628b2dbc3fc320aafaf84836119e4e3d62f1 Mon Sep 17 00:00:00 2001
From: Lars Ellenberg <lars.ellenberg@linbit.com>
Date: Fri, 20 Mar 2015 15:47:22 +0100
Subject: drbd: avoid redefinition of BITS_PER_PAGE

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)
 {


Patches currently in stable-queue which might be from lars.ellenberg@linbit.com are

queue-3.18/drbd-avoid-redefinition-of-bits_per_page.patch