linux-kernel - [PATCH v5 06/16] arm64/mm: Use helper fault_signal

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Date:   Thu, 26 Sep 2019 17:38:54 +0800
From:   Peter Xu <peterx@...hat.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     David Hildenbrand <david@...hat.com>,
        Hugh Dickins <hughd@...gle.com>,
        Maya Gokhale <gokhale2@...l.gov>,
        Jerome Glisse <jglisse@...hat.com>,
        Pavel Emelyanov <xemul@...tuozzo.com>,
        Johannes Weiner <hannes@...xchg.org>, peterx@...hat.com,
        Martin Cracauer <cracauer@...s.org>,
        Matthew Wilcox <willy@...radead.org>, Shaohua Li <shli@...com>,
        Marty McFadden <mcfadden8@...l.gov>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Denis Plotnikov <dplotnikov@...tuozzo.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Mel Gorman <mgorman@...e.de>,
        "Kirill A . Shutemov" <kirill@...temov.name>,
        "Dr . David Alan Gilbert" <dgilbert@...hat.com>
Subject: [PATCH v5 06/16] 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 <peterx@...hat.com>
---
 arch/arm64/mm/fault.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index cfd65b63f36f..4a695a44fb05 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -477,19 +477,14 @@ 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.
-- 
2.21.0