mm/nommu.c: drop unlikely inside BUG_ON()

(1) For !CONFIG_BUG cases, the bug call is a no-op, so we couldn't
    care less and the change is ok.

(2) ppc and mips, which HAVE_ARCH_BUG_ON, do not rely on branch
    predictions as it seems to be pointless[1] and thus callers should not
    be trying to push an optimization in the first place.

(3) For CONFIG_BUG and !HAVE_ARCH_BUG_ON cases, BUG_ON() contains an
    unlikely compiler flag already.

Hence, we can drop unlikely behind BUG_ON().

[1] http://lkml.iu.edu/hypermail/linux/kernel/1101.3/02289.html

Signed-off-by: Geliang Tang <geliangtang@163.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/nommu.c b/mm/nommu.c
index 1e0f168..92be862 100644 (file)
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -578,16 +578,16 @@ static noinline void validate_nommu_regions(void)
                return;
 
        last = rb_entry(lastp, struct vm_region, vm_rb);
-       BUG_ON(unlikely(last->vm_end <= last->vm_start));
-       BUG_ON(unlikely(last->vm_top < last->vm_end));
+       BUG_ON(last->vm_end <= last->vm_start);
+       BUG_ON(last->vm_top < last->vm_end);
 
        while ((p = rb_next(lastp))) {
                region = rb_entry(p, struct vm_region, vm_rb);
                last = rb_entry(lastp, struct vm_region, vm_rb);
 
-               BUG_ON(unlikely(region->vm_end <= region->vm_start));
-               BUG_ON(unlikely(region->vm_top < region->vm_end));
-               BUG_ON(unlikely(region->vm_start < last->vm_top));
+               BUG_ON(region->vm_end <= region->vm_start);
+               BUG_ON(region->vm_top < region->vm_end);
+               BUG_ON(region->vm_start < last->vm_top);
 
                lastp = p;
        }