From: Mark Brown Date: Tue, 13 Jun 2023 20:07:16 +0000 (+0100) Subject: regmap: Check for register readability before checking cache during read X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=eab5abdeb79f0f694c007c3a76a97902705c86f0;p=linux.git regmap: Check for register readability before checking cache during read Ensure that we don't return a spurious cache hit for unreadable registers (eg, with the flat cache which doesn't understand sparseness) by checking for readability before we do a cache lookup. Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20230613-b4-regmap-check-readability-before-cache-v1-1-b144c0b01ed9@kernel.org Signed-off-by: Mark Brown --- diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index 89a7f1c459c1a..fad66b309ef98 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -2897,6 +2897,9 @@ static int _regmap_read(struct regmap *map, unsigned int reg, int ret; void *context = _regmap_map_get_context(map); + if (!regmap_readable(map, reg)) + return -EIO; + if (!map->cache_bypass) { ret = regcache_read(map, reg, val); if (ret == 0) @@ -2906,9 +2909,6 @@ static int _regmap_read(struct regmap *map, unsigned int reg, if (map->cache_only) return -EBUSY; - if (!regmap_readable(map, reg)) - return -EIO; - ret = map->reg_read(context, reg, val); if (ret == 0) { if (regmap_should_log(map))