Re: [PATCH] bitops: Introduce BITS_PER_TYPE

Randy Dunlap
2018-07-06T17:49:03Z

On 07/06/18 02:44, Chris Wilson wrote:
> 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.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Andy Gospodarek <gospo@broadcom.com>
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> ---
> include/linux/bitops.h | 3 ++-
> include/linux/net_dim.h | 1 -
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/bitops.h b/include/linux/bitops.h
> index 4cac4e1a72ff..091cb17d1a9b 100644
> --- a/include/linux/bitops.h
> +++ b/include/linux/bitops.h
> @@ -11,7 +11,8 @@
> #define BIT_ULL_MASK(nr) (1ULL << ((nr) % BITS_PER_LONG_LONG))
> #define BIT_ULL_WORD(nr) ((nr) / BITS_PER_LONG_LONG)
> #define BITS_PER_BYTE 8
> -#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))
> #endif
>
> /*

doesn't <linux/net_dim.h> need to #include <linux/bitops.h> ?

> diff --git a/include/linux/net_dim.h b/include/linux/net_dim.h
> index 29ed8fd6379a..14f1734e740a 100644
> --- a/include/linux/net_dim.h
> +++ b/include/linux/net_dim.h
> @@ -326,7 +326,6 @@ 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,
>

--
~Randy