[3/4] mm, notifier: Catch sleeping/blocking for !blockable
diff mbox series

Message ID 20181210103641.31259-4-daniel.vetter@ffwll.ch
State New
Headers show
  • mmu notifier debug checks v2
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Commit Message

Daniel Vetter Dec. 10, 2018, 10:36 a.m. UTC
We need to make sure implementations don't cheat and don't have a
possible schedule/blocking point deeply burried where review can't
catch it.

I'm not sure whether this is the best way to make sure all the
might_sleep() callsites trigger, and it's a bit ugly in the code flow.
But it gets the job done.

Inspired by an i915 patch series which did exactly that, because the
rules haven't been entirely clear to us.

v2: Use the shiny new non_block_start/end annotations instead of
abusing preempt_disable/enable.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: linux-mm@kvack.org
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
 mm/mmu_notifier.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff mbox series

diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c
index ccc22f21b735..a50ed7d1ecef 100644
--- a/mm/mmu_notifier.c
+++ b/mm/mmu_notifier.c
@@ -185,7 +185,13 @@  int __mmu_notifier_invalidate_range_start(struct mm_struct *mm,
 	id = srcu_read_lock(&srcu);
 	hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) {
 		if (mn->ops->invalidate_range_start) {
-			int _ret = mn->ops->invalidate_range_start(mn, mm, start, end, blockable);
+			int _ret;
+			if (!blockable)
+				non_block_start();
+			_ret = mn->ops->invalidate_range_start(mn, mm, start, end, blockable);
+			if (!blockable)
+				non_block_end();
 			if (_ret) {
 				pr_info("%pS callback failed with %d in %sblockable context.\n",
 						mn->ops->invalidate_range_start, _ret,