linux-kernel - [PATCH net-next v5 13/21] bitmap: make bitmap_{get,set}_value8() use bitmap

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Date: Thu,  1 Feb 2024 13:22:08 +0100
From: Alexander Lobakin <aleksander.lobakin@...el.com>
To: "David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>
Cc: Alexander Lobakin <aleksander.lobakin@...el.com>,
	Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>,
	Marcin Szycik <marcin.szycik@...ux.intel.com>,
	Wojciech Drewek <wojciech.drewek@...el.com>,
	Yury Norov <yury.norov@...il.com>,
	Andy Shevchenko <andy@...nel.org>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Alexander Potapenko <glider@...gle.com>,
	Jiri Pirko <jiri@...nulli.us>,
	Ido Schimmel <idosch@...dia.com>,
	Przemek Kitszel <przemyslaw.kitszel@...el.com>,
	Simon Horman <horms@...nel.org>,
	linux-btrfs@...r.kernel.org,
	dm-devel@...hat.com,
	ntfs3@...ts.linux.dev,
	linux-s390@...r.kernel.org,
	intel-wired-lan@...ts.osuosl.org,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH net-next v5 13/21] bitmap: make bitmap_{get,set}_value8() use bitmap_{read,write}()

Now that we have generic bitmap_read() and bitmap_write(), which are
inline and try to take care of non-bound-crossing and aligned cases
to keep them optimized, collapse bitmap_{get,set}_value8() into
simple wrappers around the former ones.
bloat-o-meter shows no difference in vmlinux and -2 bytes for
gpio-pca953x.ko, which says the optimization didn't suffer due to
that change. The converted helpers have the value width embedded
and always compile-time constant and that helps a lot.

Suggested-by: Yury Norov <yury.norov@...il.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@...el.com>
---
 include/linux/bitmap.h | 38 +++++---------------------------------
 1 file changed, 5 insertions(+), 33 deletions(-)

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 9a6a27a7f675..f80e116b8f60 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -609,39 +609,6 @@ static inline void bitmap_from_u64(unsigned long *dst, u64 mask)
 	bitmap_from_arr64(dst, &mask, 64);
 }
 
-/**
- * bitmap_get_value8 - get an 8-bit value within a memory region
- * @map: address to the bitmap memory region
- * @start: bit offset of the 8-bit value; must be a multiple of 8
- *
- * Returns the 8-bit value located at the @start bit offset within the @src
- * memory region.
- */
-static inline unsigned long bitmap_get_value8(const unsigned long *map,
-					      unsigned long start)
-{
-	const size_t index = BIT_WORD(start);
-	const unsigned long offset = start % BITS_PER_LONG;
-
-	return (map[index] >> offset) & 0xFF;
-}
-
-/**
- * bitmap_set_value8 - set an 8-bit value within a memory region
- * @map: address to the bitmap memory region
- * @value: the 8-bit value; values wider than 8 bits may clobber bitmap
- * @start: bit offset of the 8-bit value; must be a multiple of 8
- */
-static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
-				     unsigned long start)
-{
-	const size_t index = BIT_WORD(start);
-	const unsigned long offset = start % BITS_PER_LONG;
-
-	map[index] &= ~(0xFFUL << offset);
-	map[index] |= value << offset;
-}
-
 /**
  * bitmap_read - read a value of n-bits from the memory region
  * @map: address to the bitmap memory region
@@ -715,6 +682,11 @@ static inline void bitmap_write(unsigned long *map, unsigned long value,
 	map[index + 1] |= (value >> space);
 }
 
+#define bitmap_get_value8(map, start)			\
+	bitmap_read(map, start, BITS_PER_BYTE)
+#define bitmap_set_value8(map, value, start)		\
+	bitmap_write(map, value, start, BITS_PER_BYTE)
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __LINUX_BITMAP_H */
-- 
2.43.0