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@xxxxxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: Paul Burton <paulburton@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: linux-m68k@xxxxxxxxxxxxxxxxxxxx Cc: linux-mips@xxxxxxxxxxxxxxx Cc: linux-csky@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> --- 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
