The .invalidate_range() callback is called by
mmu_notifier_invalidate_range() which is often called while holding
the ptl spin-lock. Therefore any implementations of this callback must
not sleep. This was originally documented when the call back was added
in commit 0f0a327fa12c ("mmu_notifier: add the callback for
mmu_notifier_invalidate_range()") but appears to have been
inadvertently removed by commit 5ff7091f5a2c ("mm, mmu_notifier:
annotate mmu notifiers with blockable invalidate callbacks").
Restore the comment to make it clear that .invalidate_range()
callbacks may not sleep.
Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx>
---
include/linux/mmu_notifier.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index 64a3e05..447d757 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -200,6 +200,9 @@ struct mmu_notifier_ops {
* external TLB range needs to be flushed. For more in depth
* discussion on this see Documentation/mm/mmu_notifier.rst
*
+ * The invalidate_range() function is called under the ptl
+ * spin-lock and not allowed to sleep.
+ *
* Note that this function might be called with just a sub-range
* of what was passed to invalidate_range_start()/end(), if
* called between those functions.
base-commit: 44c026a73be8038f03dbdeef028b642880cf1511
--
git-series 0.9.1
