[PATCH rfc -next 02/10] x86: 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/x86/mm/fault.c | 39 +++++++++++++++------------------------
 1 file changed, 15 insertions(+), 24 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 56b4f9faf8c4..3f3b8b0a87de 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1213,6 +1213,16 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
 }
 NOKPROBE_SYMBOL(do_kern_addr_fault);
 
+#ifdef CONFIG_PER_VMA_LOCK
+int arch_vma_check_access(struct vm_area_struct *vma,
+			  struct vm_locked_fault *vmlf)
+{
+	if (unlikely(access_error(vmlf->fault_code, vma)))
+		return -EINVAL;
+	return 0;
+}
+#endif
+
 /*
  * Handle faults in the user portion of the address space.  Nothing in here
  * should check X86_PF_USER without a specific justification: for almost
@@ -1231,6 +1241,7 @@ void do_user_addr_fault(struct pt_regs *regs,
 	struct mm_struct *mm;
 	vm_fault_t fault;
 	unsigned int flags = FAULT_FLAG_DEFAULT;
+	struct vm_locked_fault vmlf;
 
 	tsk = current;
 	mm = tsk->mm;
@@ -1328,27 +1339,11 @@ void do_user_addr_fault(struct pt_regs *regs,
 	}
 #endif
 
-#ifdef CONFIG_PER_VMA_LOCK
-	if (!(flags & FAULT_FLAG_USER))
-		goto lock_mmap;
-
-	vma = lock_vma_under_rcu(mm, address);
-	if (!vma)
-		goto lock_mmap;
-
-	if (unlikely(access_error(error_code, 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);
+	VM_LOCKED_FAULT_INIT(vmlf, mm, address, flags, 0, regs, error_code);
+	if (try_vma_locked_page_fault(&vmlf, &fault))
+		goto retry;
+	else if (!(fault | VM_FAULT_RETRY))
 		goto done;
-	}
-	count_vm_vma_lock_event(VMA_LOCK_RETRY);
 
 	/* Quick path to respond to signals */
 	if (fault_signal_pending(fault, regs)) {
@@ -1358,8 +1353,6 @@ void do_user_addr_fault(struct pt_regs *regs,
 						 ARCH_DEFAULT_PKEY);
 		return;
 	}
-lock_mmap:
-#endif /* CONFIG_PER_VMA_LOCK */
 
 retry:
 	vma = lock_mm_and_find_vma(mm, address, regs);
@@ -1419,9 +1412,7 @@ void do_user_addr_fault(struct pt_regs *regs,
 	}
 
 	mmap_read_unlock(mm);
-#ifdef CONFIG_PER_VMA_LOCK
 done:
-#endif
 	if (likely(!(fault & VM_FAULT_ERROR)))
 		return;
 
-- 
2.27.0