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-rw-r--r--include/linux/mm.h6
1 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 58f2263de4de..4023819837a6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -824,6 +824,10 @@ static inline bool is_device_public_page(const struct page *page)
#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
+/* 127: arbitrary random number, small enough to assemble well */
+#define page_ref_zero_or_close_to_overflow(page) \
+ ((unsigned int) page_ref_count(page) + 127u <= 127u)
+
static inline void get_page(struct page *page)
{
page = compound_head(page);
@@ -831,7 +835,7 @@ static inline void get_page(struct page *page)
* Getting a normal page or the head of a compound page
* requires to already have an elevated page->_refcount.
*/
- VM_BUG_ON_PAGE(page_ref_count(page) <= 0, page);
+ VM_BUG_ON_PAGE(page_ref_zero_or_close_to_overflow(page), page);
page_ref_inc(page);
}