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Commit c9427bc0 authored by Geliang Tang's avatar Geliang Tang Committed by Linus Torvalds
Browse files

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: default avatarGeliang Tang <geliangtang@163.com>
Acked-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1e3ee14b

mm/nommu.c

+5 −5
Original line number Diff line number Diff line
@@ -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;

	}