ARC: mm: do_page_fault refactor #4: consolidate retry related logic (02c88d14) · Commits · 戴 / test

arch/arc/mm/fault.c

+31 −29

Original line number	Diff line number	Diff line
		@@ -65,8 +65,8 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
		struct mm_struct *mm = tsk->mm;
		int si_code = SEGV_MAPERR;
		unsigned int write = 0, exec = 0, mask;
		vm_fault_t fault;
		unsigned int flags;
		vm_fault_t fault; /* handle_mm_fault() output */
		unsigned int flags; /* handle_mm_fault() input */

		/*
		* NOTE! We MUST NOT take any locks for this case. We may
		@@ -125,31 +125,40 @@ retry:
		goto bad_area;
		}

		/*
		* If for any reason at all we couldn't handle the fault,
		* make sure we exit gracefully rather than endlessly redo
		* the fault.
		*/
		fault = handle_mm_fault(vma, address, flags);

		if (fatal_signal_pending(current)) {
		/*
		* Fault retry nuances
		*/
		if (unlikely(fault & VM_FAULT_RETRY)) {

		/*
		* if fault retry, mmap_sem already relinquished by core mm
		* so OK to return to user mode (with signal handled first)
		* If fault needs to be retried, handle any pending signals
		* first (by returning to user mode).
		* mmap_sem already relinquished by core mm for RETRY case
		*/
		if (fault & VM_FAULT_RETRY) {
		if (fatal_signal_pending(current)) {
		if (!user_mode(regs))
		goto no_context;
		return;
		}
		/*
		* retry state machine
		*/
		if (flags & FAULT_FLAG_ALLOW_RETRY) {
		flags &= ~FAULT_FLAG_ALLOW_RETRY;
		flags \|= FAULT_FLAG_TRIED;
		goto retry;
		}
		}

		/*
		* Major/minor page fault accounting
		* (in case of retry we only land here once)
		*/
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);

		if (likely(!(fault & VM_FAULT_ERROR))) {
		if (flags & FAULT_FLAG_ALLOW_RETRY) {
		/* To avoid updating stats twice for retry case */
		if (fault & VM_FAULT_MAJOR) {
		tsk->maj_flt++;
		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
		@@ -160,14 +169,7 @@ retry:
		regs, address);
		}

		if (fault & VM_FAULT_RETRY) {
		flags &= ~FAULT_FLAG_ALLOW_RETRY;
		flags \|= FAULT_FLAG_TRIED;
		goto retry;
		}
		}

		/* Fault Handled Gracefully */
		/* Normal return path: fault Handled Gracefully */
		up_read(&mm->mmap_sem);
		return;
		}

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