From 39678191cd8988c811813baf4c97b43bf46094e4 Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Wed, 1 Apr 2020 21:08:10 -0700
Subject: [PATCH] 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 <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Brian Geffon <bgeffon@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.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: 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@openvz.org>
Link: http://lkml.kernel.org/r/20200220155353.8676-5-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
arch/x86/mm/fault.c | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 629fdf13f84656..552770b6af9a8b 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);
--
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