Re: [RFC V3] regmap: change bool to 1 bit variable in struct regmap

From: Markus Pargmann
Date: Mon Oct 12 2015 - 06:49:09 EST


Hi,

On Fri, Oct 09, 2015 at 03:51:22PM +0800, yalin wang wrote:
> This patch change some bool variables in struct regmap { }
> to be u8 v : 1 type, so that we can shrink the sizeof of struct regmap.
>
> Signed-off-by: yalin wang <yalin.wang2010@xxxxxxxxx>
> ---
> drivers/base/regmap/internal.h | 39 +++++++++++++++++++--------------------
> 1 file changed, 19 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
> index 3df9770..dac341c 100644
> --- a/drivers/base/regmap/internal.h
> +++ b/drivers/base/regmap/internal.h
> @@ -68,7 +68,6 @@ struct regmap {
> void *bus_context;
> const char *name;
>
> - bool async;
> spinlock_t async_lock;
> wait_queue_head_t async_waitq;
> struct list_head async_list;
> @@ -102,8 +101,26 @@ struct regmap {
> int (*reg_update_bits)(void *context, unsigned int reg,
> unsigned int mask, unsigned int val);
>
> - bool defer_caching;
> + u8 async:1;
> + u8 defer_caching:1;
> + /* if set, remember to free reg_defaults_raw */
> + u8 cache_free:1;
> + /* if set, the HW registers are known to match map->reg_defaults */
> + u8 no_sync_defaults:1;
>
> + /* if set, converts bulk read to single read */
> + u8 use_single_read:1;
> + /* if set, converts bulk read to single read */
> + u8 use_single_write:1;
> + /* if set, the device supports multi write mode */
> + u8 can_multi_write:1;
> +
> + /* if set, only the cache is modified not the HW */
> + bool cache_only;
> + /* if set, only the HW is modified not the cache */
> + bool cache_bypass;
> + /* if set, the cache contains newer data than the HW */
> + bool cache_dirty;

Why are these last three variables just moved and not changed to u8 of
size 1?

Regards,

Markus

> u8 read_flag_mask;
> u8 write_flag_mask;
>
> @@ -124,31 +141,13 @@ struct regmap {
> /* number of entries in reg_defaults_raw */
> unsigned int num_reg_defaults_raw;
>
> - /* if set, only the cache is modified not the HW */
> - bool cache_only;
> - /* if set, only the HW is modified not the cache */
> - bool cache_bypass;
> - /* if set, remember to free reg_defaults_raw */
> - bool cache_free;
> -
> struct reg_default *reg_defaults;
> const void *reg_defaults_raw;
> void *cache;
> - /* if set, the cache contains newer data than the HW */
> - bool cache_dirty;
> - /* if set, the HW registers are known to match map->reg_defaults */
> - bool no_sync_defaults;
>
> struct reg_sequence *patch;
> int patch_regs;
>
> - /* if set, converts bulk read to single read */
> - bool use_single_read;
> - /* if set, converts bulk read to single read */
> - bool use_single_write;
> - /* if set, the device supports multi write mode */
> - bool can_multi_write;
> -
> /* if set, raw reads/writes are limited to this size */
> size_t max_raw_read;
> size_t max_raw_write;
> --
> 1.9.1
>
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