linux-kernel - [PATCH RESEND v6 05/16] arc/mm: Use helper fault_signal

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Message-Id: <20200220155843.9172-1-peterx@redhat.com>
Date:   Thu, 20 Feb 2020 10:58:43 -0500
From:   Peter Xu <peterx@...hat.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     Peter Xu <peterx@...hat.com>, Martin Cracauer <cracauer@...s.org>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Hugh Dickins <hughd@...gle.com>,
        Jerome Glisse <jglisse@...hat.com>,
        "Kirill A . Shutemov" <kirill@...temov.name>,
        Matthew Wilcox <willy@...radead.org>,
        Pavel Emelyanov <xemul@...tuozzo.com>,
        Brian Geffon <bgeffon@...gle.com>,
        Maya Gokhale <gokhale2@...l.gov>,
        Denis Plotnikov <dplotnikov@...tuozzo.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Johannes Weiner <hannes@...xchg.org>,
        "Dr . David Alan Gilbert" <dgilbert@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Marty McFadden <mcfadden8@...l.gov>,
        David Hildenbrand <david@...hat.com>,
        Bobby Powers <bobbypowers@...il.com>,
        Mel Gorman <mgorman@...e.de>
Subject: [PATCH RESEND v6 05/16] arc/mm: Use helper fault_signal_pending()

Let ARC to use the new helper fault_signal_pending() by moving the
signal check out of the retry logic as standalone.  This should also
helps to simplify the code a bit.

Signed-off-by: Peter Xu <peterx@...hat.com>
---
 arch/arc/mm/fault.c | 34 +++++++++++++---------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index fb86bc3e9b35..6eb821a59b49 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -133,29 +133,21 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
 
 	fault = handle_mm_fault(vma, address, flags);
 
+	/* Quick path to respond to signals */
+	if (fault_signal_pending(fault, regs)) {
+		if (!user_mode(regs))
+			goto no_context;
+		return;
+	}
+
 	/*
-	 * Fault retry nuances
+	 * Fault retry nuances, mmap_sem already relinquished by core mm
 	 */
-	if (unlikely(fault & VM_FAULT_RETRY)) {
-
-		/*
-		 * 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 (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;
-		}
+	if (unlikely((fault & VM_FAULT_RETRY) &&
+		     (flags & FAULT_FLAG_ALLOW_RETRY))) {
+		flags &= ~FAULT_FLAG_ALLOW_RETRY;
+		flags |= FAULT_FLAG_TRIED;
+		goto retry;
 	}
 
 bad_area:
-- 
2.24.1