memblock: memblock should be able to handle zero length operations
authorTejun Heo <tj@kernel.org>
Fri, 20 Apr 2012 15:31:34 +0000 (08:31 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 20 Apr 2012 18:18:46 +0000 (11:18 -0700)
commitb3dc627cabb33fc95f93da78457770c1b2a364d2
treee37cae7a574b808b6da48e4c93e81f170efce078
parent310eb776501af8412c570c4bcddc9ab5cecf3d7a
memblock: memblock should be able to handle zero length operations

Commit 24aa07882b ("memblock, x86: Replace memblock_x86_reserve/
free_range() with generic ones") replaced x86 specific memblock
operations with the generic ones; unfortunately, it lost zero length
operation handling in the process making the kernel panic if somebody
tries to reserve zero length area.

There isn't much to be gained by being cranky to zero length operations
and panicking is almost the worst response.  Drop the BUG_ON() in
memblock_reserve() and update memblock_add_region/isolate_range() so
that all zero length operations are handled as noops.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
Reported-by: Valere Monseur <valere.monseur@ymail.com>
Bisected-by: Joseph Freeman <jfree143dev@gmail.com>
Tested-by: Joseph Freeman <jfree143dev@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=43098
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/memblock.c