linux-kernel - [PATCH] mm: clean up obsolete check on space in page->flags

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Date:   Sun,  8 Dec 2019 11:35:07 -0700
From:   Yu Zhao <yuzhao@...gle.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Arnd Bergmann <arnd@...db.de>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Yu Zhao <yuzhao@...gle.com>
Subject: [PATCH] mm: clean up obsolete check on space in page->flags

The check in linux/mm.h was intended to make sure we don't overrun
page flags. But it's obsolete because it doesn't include
LAST_CPUPID_WIDTH nor KASAN_TAG_WIDTH.

Just remove check since we already have it covered in
linux/page-flags-layout.h (near the end of the file).

Signed-off-by: Yu Zhao <yuzhao@...gle.com>
---
 include/linux/mm.h | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index c97ea3b694e6..2e7596cce9d8 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -921,10 +921,6 @@ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);
 
 #define ZONEID_PGSHIFT		(ZONEID_PGOFF * (ZONEID_SHIFT != 0))
 
-#if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
-#error SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH > BITS_PER_LONG - NR_PAGEFLAGS
-#endif
-
 #define ZONES_MASK		((1UL << ZONES_WIDTH) - 1)
 #define NODES_MASK		((1UL << NODES_WIDTH) - 1)
 #define SECTIONS_MASK		((1UL << SECTIONS_WIDTH) - 1)
-- 
2.24.0.393.g34dc348eaf-goog