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SubjectRe: [PATCH] regcache: Use bsearch() to search the register defaults
On Tue, Oct 04, 2011 at 10:06:36PM +0100, Mark Brown wrote:
> Rather than open coding a binary search use the standard bsearch() using
> the comparison function we're already using for sort() on insert. This
> fixes a lockup I was observing due to iterating on min <= max rather
> than min < max when we fail to look up.
>
> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
> ---
> drivers/base/regmap/regcache.c | 40 ++++++++++++++++++++--------------------
> 1 files changed, 20 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
> index 18ab5b3..bf82783 100644
> --- a/drivers/base/regmap/regcache.c
> +++ b/drivers/base/regmap/regcache.c
> @@ -13,6 +13,7 @@
> #include <linux/slab.h>
> #include <linux/export.h>
> #include <trace/events/regmap.h>
> +#include <linux/bsearch.h>
> #include <linux/sort.h>
>
> #include "internal.h"
> @@ -356,25 +357,7 @@ unsigned int regcache_get_val(const void *base, unsigned int idx,
> return -1;
> }
>
> -int regcache_lookup_reg(struct regmap *map, unsigned int reg)
> -{
> - unsigned int min, max, index;
> -
> - min = 0;
> - max = map->num_reg_defaults - 1;
> - do {
> - index = (min + max) / 2;
> - if (map->reg_defaults[index].reg == reg)
> - return index;
> - if (map->reg_defaults[index].reg < reg)
> - min = index + 1;
> - else
> - max = index;
> - } while (min <= max);
> - return -1;
> -}
> -
> -static int regcache_insert_cmp(const void *a, const void *b)
> +static int regcache_default_cmp(const void *a, const void *b)
> {
> const struct reg_default *_a = a;
> const struct reg_default *_b = b;
> @@ -382,6 +365,23 @@ static int regcache_insert_cmp(const void *a, const void *b)
> return _a->reg - _b->reg;
> }
>
> +int regcache_lookup_reg(struct regmap *map, unsigned int reg)
> +{
> + struct reg_default key;
> + struct reg_default *r;
> +
> + key.reg = reg;
> + key.def = 0;
> +
> + r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
> + sizeof(struct reg_default), regcache_default_cmp);
> +
> + if (r)
> + return r - map->reg_defaults;
> + else
> + return -1;
> +}
> +
> int regcache_insert_reg(struct regmap *map, unsigned int reg,
> unsigned int val)
> {
> @@ -397,6 +397,6 @@ int regcache_insert_reg(struct regmap *map, unsigned int reg,
> map->reg_defaults[map->num_reg_defaults - 1].reg = reg;
> map->reg_defaults[map->num_reg_defaults - 1].def = val;
> sort(map->reg_defaults, map->num_reg_defaults,
> - sizeof(struct reg_default), regcache_insert_cmp, NULL);
> + sizeof(struct reg_default), regcache_default_cmp, NULL);
> return 0;
> }
> --
> 1.7.6.3
>

Looks good :)

Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>


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