From: Peter Xu <peterx@xxxxxxxxxx> Subject: 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. Link: http://lkml.kernel.org/r/20200220155353.8676-5-peterx@xxxxxxxxxx Signed-off-by: Peter Xu <peterx@xxxxxxxxxx> Tested-by: Brian Geffon <bgeffon@xxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Bobby Powers <bobbypowers@xxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Denis Plotnikov <dplotnikov@xxxxxxxxxxxxx> Cc: "Dr . David Alan Gilbert" <dgilbert@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Jerome Glisse <jglisse@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: "Kirill A . Shutemov" <kirill@xxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Martin Cracauer <cracauer@xxxxxxxx> Cc: Marty McFadden <mcfadden8@xxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Maya Gokhale <gokhale2@xxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> Cc: Pavel Emelyanov <xemul@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/mm/fault.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-) --- a/arch/x86/mm/fault.c~x86-mm-use-helper-fault_signal_pending +++ a/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); _
