From 82b7a618397c80736506c05d9add4aaea91297e8 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 3 Apr 2024 16:38:04 +0800 Subject: [PATCH] s390: mm: accelerate pagefault when badaccess The vm_flags of vma already checked under per-VMA lock, if it is a bad access, directly handle error, no need to retry with mmap_lock again. Since the page faut is handled under per-VMA lock, count it as a vma lock event with VMA_LOCK_SUCCESS. Link: https://lkml.kernel.org/r/20240403083805.1818160-7-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Heiko Carstens Cc: Albert Ou Cc: Alexander Gordeev Cc: Andy Lutomirski Cc: Catalin Marinas Cc: Christophe Leroy Cc: Dave Hansen Cc: Gerald Schaefer Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Russell King Cc: Suren Baghdasaryan Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/s390/mm/fault.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 0c66b32e0f9f..65747f15dbec 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -325,7 +325,8 @@ static void do_exception(struct pt_regs *regs, int access) goto lock_mmap; if (!(vma->vm_flags & access)) { vma_end_read(vma); - goto lock_mmap; + count_vm_vma_lock_event(VMA_LOCK_SUCCESS); + return handle_fault_error_nolock(regs, SEGV_ACCERR); } fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))