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.
Cc: Guo Ren <guoren@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <redacted>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Mike Rapoport <redacted>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-mips@vger.kernel.org
Cc: linux-csky@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <redacted>
---
This patch applies on v5.6-rc3 along with the recent VMA series V2
(https://patchwork.kernel.org/cover/11399319/). This has only been
build tested for mips and m68k platforms.
arch/csky/mm/fault.c | 2 +-
arch/m68k/mm/fault.c | 2 +-
arch/mips/mm/fault.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
index 4b3511b8298d..01caae98c350 100644
--- a/arch/csky/mm/fault.c
+++ b/arch/csky/mm/fault.c
@@ -137,7 +137,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
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 d5131ec5d923..d5dd75ed77f1 100644
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -125,7 +125,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
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 5b9f947bfa32..db4b51a40c58 100644
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -142,7 +142,7 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,
goto bad_area;
}
} else {
- if (!vma_is_accessible(vma))
+ if (unlikely(!vma_is_accessible(vma)))
goto bad_area;
}
}--
2.20.1