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From:   Matthew Wilcox <willy@infradead.org>
To:     linux-fsdevel@vger.kernel.org
Cc:     "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH v4 06/36] mm: Introduce offset_in_thp
Date:   Fri, 15 May 2020 06:16:26 -0700
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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Mirroring offset_in_page(), this gives you the offset within this
particular page, no matter what size page it is.  It optimises down
to offset_in_page() if CONFIG_TRANSPARENT_HUGEPAGE is not set.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/mm.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 088acbda722d..9a55dce6a535 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1577,6 +1577,7 @@ static inline void clear_page_pfmemalloc(struct page *page)
 extern void pagefault_out_of_memory(void);
 
 #define offset_in_page(p)	((unsigned long)(p) & ~PAGE_MASK)
+#define offset_in_thp(page, p)	((unsigned long)(p) & (thp_size(page) - 1))
 
 /*
  * Flags passed to show_mem() and show_free_areas() to suppress output in
-- 
2.26.2