Commit 5093c587 authored Apr 06, 2020 by Anshuman Khandual Committed by Linus Torvalds Apr 07, 2020

mm/vma: append unlikely() while testing VMA access permissions



It is unlikely that an inaccessible VMA without required permission flags
will get a page fault.  Hence lets just append unlikely() directive to
such checks in order to improve performance while also standardizing it
across various platforms.

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Link: http://lkml.kernel.org/r/1582525304-32113-1-git-send-email-anshuman.khandual@arm.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent a0137f16

arch/csky/mm/fault.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -141,7 +141,7 @@ good_area:
		if (!(vma->vm_flags & VM_WRITE))
		goto bad_area;
		} else {
		if (!vma_is_accessible(vma))
		if (unlikely(!vma_is_accessible(vma)))
		goto bad_area;
		}

arch/m68k/mm/fault.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -125,7 +125,7 @@ good_area:
		case 1: /* read, present */
		goto acc_err;
		case 0: /* read, not present */
		if (!vma_is_accessible(vma))
		if (unlikely(!vma_is_accessible(vma)))
		goto acc_err;
		}

arch/mips/mm/fault.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -142,7 +142,7 @@ good_area:
		goto bad_area;
		}
		} else {
		if (!vma_is_accessible(vma))
		if (unlikely(!vma_is_accessible(vma)))
		goto bad_area;
		}
		}

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