include/linux/bitops.h: introduce BITS_PER_TYPE

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.ukSigned-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>

include/linux/bitops.h

@@ -4,7 +4,8 @@
 #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);

include/linux/net_dim.h

@@ -363,7 +363,6 @@ static inline void net_dim_sample(u16 event_ctr,
 }
 
 #define NET_DIM_NEVENTS 64
-#define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE)
 #define BIT_GAP(bits, end, start) ((((end) - (start)) + BIT_ULL(bits)) & (BIT_ULL(bits) - 1))
 
 static inline void net_dim_calc_stats(struct net_dim_sample *start,