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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 <wangkefeng.wang@huawei.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.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: Suren Baghdasaryan <surenb@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

authored by

Kefeng Wang and committed by
Andrew Morton
82b7a618 cd1c91b8

+2 -1
+2 -1
arch/s390/mm/fault.c
··· 325 325 goto lock_mmap; 326 326 if (!(vma->vm_flags & access)) { 327 327 vma_end_read(vma); 328 - goto lock_mmap; 328 + count_vm_vma_lock_event(VMA_LOCK_SUCCESS); 329 + return handle_fault_error_nolock(regs, SEGV_ACCERR); 329 330 } 330 331 fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); 331 332 if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))