arm64/mm: use helper fault_signal_pending()

Let the arm64 fault handling to use the new fault_signal_pending() helper,
by moving the signal handling out of the retry logic.

Signed-off-by: Peter Xu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Tested-by: Brian Geffon <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Bobby Powers <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Denis Plotnikov <[email protected]>
Cc: "Dr . David Alan Gilbert" <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Jerome Glisse <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: "Kirill A . Shutemov" <[email protected]>
Cc: Martin Cracauer <[email protected]>
Cc: Marty McFadden <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Maya Gokhale <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

Author: xzpeter

arch/arm64/mm/fault.c

@@ -513,19 +513,14 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
 	fault = __do_page_fault(mm, addr, mm_flags, vm_flags);
 	major |= fault & VM_FAULT_MAJOR;
 
-	if (fault & VM_FAULT_RETRY) {
-		/*
-		 * If we need to retry but a fatal signal is pending,
-		 * handle the signal first. We do not need to release
-		 * the mmap_sem because it would already be released
-		 * in __lock_page_or_retry in mm/filemap.c.
-		 */
-		if (fatal_signal_pending(current)) {
-			if (!user_mode(regs))
-				goto no_context;
-			return 0;
-		}
+	/* Quick path to respond to signals */
+	if (fault_signal_pending(fault, regs)) {
+		if (!user_mode(regs))
+			goto no_context;
+		return 0;
+	}
 
+	if (fault & VM_FAULT_RETRY) {
 		/*
 		 * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk of
 		 * starvation.