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arm: mm: accelerate pagefault when VM_FAULT_BADACCESS

The vm_flags of vma already checked under per-VMA lock, if it is a bad
access, directly set fault to VM_FAULT_BADACCESS and 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/20240403083805.1818160-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

authored by

Kefeng Wang and committed by
Andrew Morton
15e4a5f5 faab3d0f

+3 -1
+3 -1
arch/arm/mm/fault.c
··· 294 294 295 295 if (!(vma->vm_flags & vm_flags)) { 296 296 vma_end_read(vma); 297 - goto lock_mmap; 297 + count_vm_vma_lock_event(VMA_LOCK_SUCCESS); 298 + fault = VM_FAULT_BADACCESS; 299 + goto bad_area; 298 300 } 299 301 fault = handle_mm_fault(vma, addr, flags | FAULT_FLAG_VMA_LOCK, regs); 300 302 if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))