From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
All architectures now have a definition of
clear_bit_unlock_is_negative_byte(), either their own or through
asm-generic/bitops/lock.h
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
---
mm/filemap.c | 23 -----------------------
1 file changed, 23 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 23a051a7ef0f..e475117e89eb 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1248,29 +1248,6 @@ void add_page_wait_queue(struct page *page, wait_queue_entry_t *waiter)
}
EXPORT_SYMBOL_GPL(add_page_wait_queue);
-#ifndef clear_bit_unlock_is_negative_byte
-
-/*
- * PG_waiters is the high bit in the same byte as PG_lock.
- *
- * On x86 (and on many other architectures), we can clear PG_lock and
- * test the sign bit at the same time. But if the architecture does
- * not support that special operation, we just do this all by hand
- * instead.
- *
- * The read of PG_waiters has to be after (or concurrently with) PG_locked
- * being cleared, but a memory barrier should be unneccssary since it is
- * in the same byte as PG_locked.
- */
-static inline bool clear_bit_unlock_is_negative_byte(long nr, volatile void *mem)
-{
- clear_bit_unlock(nr, mem);
- /* smp_mb__after_atomic(); */
- return test_bit(PG_waiters, mem);
-}
-
-#endif
-
/**
* unlock_page - unlock a locked page
* @page: the page
--
2.25.1
