[PATCH 4.9 39/88] include/linux/bitops.h: introduce BITS_PER_TYPE

Greg Kroah-Hartman
2020-03-10T12:47:12Z

From: Chris Wilson <chris@chris-wilson.co.uk>

commit 9144d75e22cad3c89e6b2ccab551db9ee28d250a upstream.

net_dim.h has a rather useful extension to BITS_PER_BYTE to compute the
number of bits in a type (BITS_PER_BYTE * sizeof(T)), so promote the macro
to bitops.h, alongside BITS_PER_BYTE, for wider usage.

Link: http://lkml.kernel.org/r/20180706094458.14116-1-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andy Gospodarek <gospo@broadcom.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[only take the bitops.h portion for stable kernels - gregkh]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/linux/bitops.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -3,7 +3,8 @@
#include <asm/types.h>
#include <linux/bits.h>

-#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
+#define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE)
+#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_TYPE(long))

extern unsigned int __sw_hweight8(unsigned int w);
extern unsigned int __sw_hweight16(unsigned int w);