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>

diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
index a6e8230..4e6dc68 100644 (file)
--- a/arch/csky/mm/fault.c
+++ b/arch/csky/mm/fault.c
@@ -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;
        }
 

diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
index 0c4a21a..3bfb5c8 100644 (file)
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -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;
        }
 

diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c
index fb048ba..f8d62cd 100644 (file)
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -142,7 +142,7 @@ good_area:
                                goto bad_area;
                        }
                } else {
-                       if (!vma_is_accessible(vma))
+                       if (unlikely(!vma_is_accessible(vma)))
                                goto bad_area;
                }
        }