[PATCH rfc v2 05/10] powerpc: mm: use try_vma_locked_page_fault()

[Kefeng Wang]

Use new try_vma_locked_page_fault() helper to simplify code.
No functional change intended.

Signed-off-by: Kefeng Wang <wangkefeng.wang at huawei.com>
---
 arch/powerpc/mm/fault.c | 66 ++++++++++++++++++++---------------------
 1 file changed, 32 insertions(+), 34 deletions(-)

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index b1723094d464..52f9546e020e 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -391,6 +391,22 @@ static int page_fault_is_bad(unsigned long err)
 #define page_fault_is_bad(__err)	((__err) & DSISR_BAD_FAULT_32S)
 #endif
 
+#ifdef CONFIG_PER_VMA_LOCK
+bool arch_vma_access_error(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	int is_exec = TRAP(vmf->regs) == INTERRUPT_INST_STORAGE;
+	int is_write = page_fault_is_write(vmf->fault_code);
+
+	if (unlikely(access_pkey_error(is_write, is_exec,
+				(vmf->fault_code & DSISR_KEYFAULT), vma)))
+		return true;
+
+	if (unlikely(access_error(is_write, is_exec, vma)))
+		return true;
+	return false;
+}
+#endif
+
 /*
  * For 600- and 800-family processors, the error_code parameter is DSISR
  * for a data fault, SRR1 for an instruction fault.
@@ -407,12 +423,18 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
 {
 	struct vm_area_struct * vma;
 	struct mm_struct *mm = current->mm;
-	unsigned int flags = FAULT_FLAG_DEFAULT;
 	int is_exec = TRAP(regs) == INTERRUPT_INST_STORAGE;
 	int is_user = user_mode(regs);
 	int is_write = page_fault_is_write(error_code);
 	vm_fault_t fault, major = 0;
 	bool kprobe_fault = kprobe_page_fault(regs, 11);
+	struct vm_fault vmf = {
+		.real_address = address,
+		.fault_code = error_code,
+		.regs = regs,
+		.flags = FAULT_FLAG_DEFAULT,
+	};
+
 
 	if (unlikely(debugger_fault_handler(regs) || kprobe_fault))
 		return 0;
@@ -463,45 +485,21 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
 	 * mmap_lock held
 	 */
 	if (is_user)
-		flags |= FAULT_FLAG_USER;
+		vmf.flags |= FAULT_FLAG_USER;
 	if (is_write)
-		flags |= FAULT_FLAG_WRITE;
+		vmf.flags |= FAULT_FLAG_WRITE;
 	if (is_exec)
-		flags |= FAULT_FLAG_INSTRUCTION;
+		vmf.flags |= FAULT_FLAG_INSTRUCTION;
 
-	if (!(flags & FAULT_FLAG_USER))
-		goto lock_mmap;
-
-	vma = lock_vma_under_rcu(mm, address);
-	if (!vma)
-		goto lock_mmap;
-
-	if (unlikely(access_pkey_error(is_write, is_exec,
-				       (error_code & DSISR_KEYFAULT), vma))) {
-		vma_end_read(vma);
-		goto lock_mmap;
-	}
-
-	if (unlikely(access_error(is_write, is_exec, vma))) {
-		vma_end_read(vma);
-		goto lock_mmap;
-	}
-
-	fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs);
-	if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))
-		vma_end_read(vma);
-
-	if (!(fault & VM_FAULT_RETRY)) {
-		count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
+	fault = try_vma_locked_page_fault(&vmf);
+	if (fault == VM_FAULT_NONE)
+		goto retry;
+	if (!(fault & VM_FAULT_RETRY))
 		goto done;
-	}
-	count_vm_vma_lock_event(VMA_LOCK_RETRY);
 
 	if (fault_signal_pending(fault, regs))
 		return user_mode(regs) ? 0 : SIGBUS;
 
-lock_mmap:
-
 	/* When running in the kernel we expect faults to occur only to
 	 * addresses in user space.  All other faults represent errors in the
 	 * kernel and should generate an OOPS.  Unfortunately, in the case of an
@@ -528,7 +526,7 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
 	 * make sure we exit gracefully rather than endlessly redo
 	 * the fault.
 	 */
-	fault = handle_mm_fault(vma, address, flags, regs);
+	fault = handle_mm_fault(vma, address, vmf.flags, regs);
 
 	major |= fault & VM_FAULT_MAJOR;
 
@@ -544,7 +542,7 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
 	 * case.
 	 */
 	if (unlikely(fault & VM_FAULT_RETRY)) {
-		flags |= FAULT_FLAG_TRIED;
+		vmf.flags |= FAULT_FLAG_TRIED;
 		goto retry;
 	}
 
-- 
2.27.0