mm: wrap calls to set_pte_at_notify with invalidate_range_start and invalidate_range_end

In order to allow sleeping during invalidate_page mmu notifier calls, we
need to avoid calling when holding the PT lock.  In addition to its direct
calls, invalidate_page can also be called as a substitute for a change_pte
call, in case the notifier client hasn't implemented change_pte.

This patch drops the invalidate_page call from change_pte, and instead
wraps all calls to change_pte with invalidate_range_start and
invalidate_range_end calls.

Note that change_pte still cannot sleep after this patch, and that clients
implementing change_pte should not take action on it in case the number of
outstanding invalidate_range_start calls is larger than one, otherwise
they might miss a later invalidation.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Cc: Andrea Arcangeli <andrea@qumranet.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Haggai Eran <haggaie@mellanox.com>
Cc: Shachar Raindel <raindel@mellanox.com>
Cc: Liran Liss <liranl@mellanox.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 1d9c0a98596..98256bc71ee 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -141,10 +141,14 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
         spinlock_t *ptl;
         pte_t *ptep;
         int err;
+        /* For mmu_notifiers */
+        const unsigned long mmun_start = addr;
+        const unsigned long mmun_end   = addr + PAGE_SIZE;
 
         /* For try_to_free_swap() and munlock_vma_page() below */
         lock_page(page);
 
+        mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
         err = -EAGAIN;
         ptep = page_check_address(page, mm, addr, &ptl, 0);
         if (!ptep)
@@ -173,6 +177,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
 
         err = 0;
  unlock:
+        mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
         unlock_page(page);
         return err;
 }