Bulk reads may potentially read a lot of registers and regmap_read will
take and release the regmap lock for each register. Avoid bouncing
the lock so frequently by holding the lock locally and calling
_regmap_read instead. This also has the nice side-effect that all the
reads will be done atomically so no other threads can sneak a write in
during the regmap_bulk_read.
Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/base/regmap/regmap.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 93d4218c5569..872be065e3fe 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -2674,6 +2674,8 @@ int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
if (!IS_ALIGNED(reg, map->reg_stride))
return -EINVAL;
+ if (val_count == 0)
+ return -EINVAL;
if (map->bus && map->format.parse_inplace && (vol || map->cache_type == REGCACHE_NONE)) {
ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
@@ -2690,13 +2692,15 @@ int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
u16 *u16 = val;
u8 *u8 = val;
+ map->lock(map->lock_arg);
+
for (i = 0; i < val_count; i++) {
unsigned int ival;
- ret = regmap_read(map, reg + regmap_get_offset(map, i),
- &ival);
+ ret = _regmap_read(map, reg + regmap_get_offset(map, i),
+ &ival);
if (ret != 0)
- return ret;
+ goto out;
switch (map->format.val_bytes) {
#ifdef CONFIG_64BIT
@@ -2714,12 +2718,16 @@ int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
u8[i] = ival;
break;
default:
- return -EINVAL;
+ ret = -EINVAL;
+ goto out;
}
}
+
+out:
+ map->unlock(map->lock_arg);
}
- return 0;
+ return ret;
}
EXPORT_SYMBOL_GPL(regmap_bulk_read);
--
2.11.0
--
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