x86/mm: use helper fault_signal_pending()

Let's move the fatal signal check even earlier so that we can directly use
the new fault_signal_pending() in x86 mm code.

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]>

1 files changed, 13 insertions, 15 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 629fdf13f846..552770b6af9a 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1464,27 +1464,25 @@ good_area:
 	fault = handle_mm_fault(vma, address, flags);
 	major |= fault & VM_FAULT_MAJOR;
 
+	/* Quick path to respond to signals */
+	if (fault_signal_pending(fault, regs)) {
+		if (!user_mode(regs))
+			no_context(regs, hw_error_code, address, SIGBUS,
+				   BUS_ADRERR);
+		return;
+	}
+
 	/*
 	 * If we need to retry the mmap_sem has already been released,
 	 * and if there is a fatal signal pending there is no guarantee
 	 * that we made any progress. Handle this case first.
 	 */
-	if (unlikely(fault & VM_FAULT_RETRY)) {
+	if (unlikely((fault & VM_FAULT_RETRY) &&
+		     (flags & FAULT_FLAG_ALLOW_RETRY))) {
 		/* Retry at most once */
-		if (flags & FAULT_FLAG_ALLOW_RETRY) {
-			flags &= ~FAULT_FLAG_ALLOW_RETRY;
-			flags |= FAULT_FLAG_TRIED;
-			if (!fatal_signal_pending(tsk))
-				goto retry;
-		}
-
-		/* User mode? Just return to handle the fatal exception */
-		if (flags & FAULT_FLAG_USER)
-			return;
-
-		/* Not returning to user mode? Handle exceptions or die: */
-		no_context(regs, hw_error_code, address, SIGBUS, BUS_ADRERR);
-		return;
+		flags &= ~FAULT_FLAG_ALLOW_RETRY;
+		flags |= FAULT_FLAG_TRIED;
+		goto retry;
 	}
 
 	up_read(&mm->mmap_sem);