[PATCH v2 2/5] mm: Use rwsem assertion macros for mmap_lock

Matthew Wilcox (Oracle)
2023-10-07T20:36:27Z

This slightly strengthens our write assertion when lockdep is disabled.
It also downgrades us from BUG_ON to WARN_ON, but I think that's an
improvement. I don't think dumping the mm_struct was all that valuable;
the call chain is what's important.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/mmap_lock.h | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h
index 8d38dcb6d044..de9dc20b01ba 100644
--- a/include/linux/mmap_lock.h
+++ b/include/linux/mmap_lock.h
@@ -60,16 +60,14 @@ static inline void __mmap_lock_trace_released(struct mm_struct *mm, bool write)

#endif /* CONFIG_TRACING */

-static inline void mmap_assert_locked(struct mm_struct *mm)
+static inline void mmap_assert_locked(const struct mm_struct *mm)
{
- lockdep_assert_held(&mm->mmap_lock);
- VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
+ rwsem_assert_held(&mm->mmap_lock);
}

-static inline void mmap_assert_write_locked(struct mm_struct *mm)
+static inline void mmap_assert_write_locked(const struct mm_struct *mm)
{
- lockdep_assert_held_write(&mm->mmap_lock);
- VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
+ rwsem_assert_held_write(&mm->mmap_lock);
}

#ifdef CONFIG_PER_VMA_LOCK
--
2.40.1