+ arc-mm-use-helper-fault_signal_pending.patch added to -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: arc/mm: use helper fault_signal_pending()
has been added to the -mm tree.  Its filename is
     arc-mm-use-helper-fault_signal_pending.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/arc-mm-use-helper-fault_signal_pending.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/arc-mm-use-helper-fault_signal_pending.patch

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------------------------------------------------------
From: Peter Xu <peterx@redhat.com>
Subject: 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.

Link: http://lkml.kernel.org/r/20200220155843.9172-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/arc/mm/fault.c |   34 +++++++++++++---------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

--- a/arch/arc/mm/fault.c~arc-mm-use-helper-fault_signal_pending
+++ a/arch/arc/mm/fault.c
@@ -133,29 +133,21 @@ retry:
 
 	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:
_

Patches currently in -mm which might be from peterx@redhat.com are

mm-gup-rename-nonblocking-to-locked-where-proper.patch
mm-gup-fix-__get_user_pages-on-fault-retry-of-hugetlb.patch
mm-introduce-fault_signal_pending.patch
x86-mm-use-helper-fault_signal_pending.patch
arc-mm-use-helper-fault_signal_pending.patch
arm64-mm-use-helper-fault_signal_pending.patch
powerpc-mm-use-helper-fault_signal_pending.patch
sh-mm-use-helper-fault_signal_pending.patch
mm-return-faster-for-non-fatal-signals-in-user-mode-faults.patch
userfaultfd-dont-retake-mmap_sem-to-emulate-nopage.patch
mm-introduce-fault_flag_default.patch
mm-introduce-fault_flag_interruptible.patch
mm-allow-vm_fault_retry-for-multiple-times.patch
mm-gup-allow-vm_fault_retry-for-multiple-times.patch
mm-gup-allow-to-react-to-fatal-signals.patch
mm-userfaultfd-honor-fault_flag_killable-in-fault-path.patch
mm-merge-parameters-for-change_protection.patch
userfaultfd-wp-apply-_page_uffd_wp-bit.patch
userfaultfd-wp-drop-_page_uffd_wp-properly-when-fork.patch
userfaultfd-wp-add-pmd_swp_uffd_wp-helpers.patch
userfaultfd-wp-support-swap-and-page-migration.patch
khugepaged-skip-collapse-if-uffd-wp-detected.patch
userfaultfd-wp-dont-wake-up-when-doing-write-protect.patch
userfaultfd-wp-declare-_uffdio_writeprotect-conditionally.patch
userfaultfd-selftests-refactor-statistics.patch
userfaultfd-selftests-add-write-protect-test.patch