From 810e24e009cf71bf85a1524f272a744c54ca6591 Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Mon, 26 Aug 2019 22:14:25 +0200
Subject: [PATCH] mm/mmu_notifiers: annotate with might_sleep()
Since mmu notifiers don't exist for many processes, but could block in
interesting places, add some annotations. This should help make sure the
core mm keeps up its end of the mmu notifier contract.
The checks here are outside of all notifier checks because of that.
They compile away without CONFIG_DEBUG_ATOMIC_SLEEP.
Link: https://lore.kernel.org/r/20190826201425.17547-6-daniel.vetter@ffwll.ch
Suggested-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
---
include/linux/mmu_notifier.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index 4dfe996dafd29..1bd8e6a09a3c2 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -343,6 +343,8 @@ static inline void mmu_notifier_change_pte(struct mm_struct *mm,
static inline void
mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range)
{
+ might_sleep();
+
lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
if (mm_has_notifiers(range->mm)) {
range->flags |= MMU_NOTIFIER_RANGE_BLOCKABLE;
@@ -368,6 +370,9 @@ mmu_notifier_invalidate_range_start_nonblock(struct mmu_notifier_range *range)
static inline void
mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range)
{
+ if (mmu_notifier_range_blockable(range))
+ might_sleep();
+
if (mm_has_notifiers(range->mm))
__mmu_notifier_invalidate_range_end(range, false);
}
--
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