[PATCH v2 1/3] regmap: debugfs: use snprintf return value in regmap_reg_ranges_read_file()

From: Rasmus Villemoes
Date: Wed Sep 30 2015 - 14:32:24 EST


Calling strlen() no less than three times on entry is silly. Since
we're formatting into a buffer with plenty of room, there's no chance
of truncation, so snprintf() has actually returned the value we want,
meaning we don't even have to call strlen once.

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
drivers/base/regmap/regmap-debugfs.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index f42f2bac6466..d26b9c3ab812 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -339,6 +339,7 @@ static ssize_t regmap_reg_ranges_read_file(struct file *file,
char *buf;
char *entry;
int ret;
+ unsigned entry_len;

if (*ppos < 0 || !count)
return -EINVAL;
@@ -366,18 +367,18 @@ static ssize_t regmap_reg_ranges_read_file(struct file *file,
p = 0;
mutex_lock(&map->cache_lock);
list_for_each_entry(c, &map->debugfs_off_cache, list) {
- snprintf(entry, PAGE_SIZE, "%x-%x",
- c->base_reg, c->max_reg);
+ entry_len = snprintf(entry, PAGE_SIZE, "%x-%x",
+ c->base_reg, c->max_reg);
if (p >= *ppos) {
- if (buf_pos + 1 + strlen(entry) > count)
+ if (buf_pos + 1 + entry_len > count)
break;
snprintf(buf + buf_pos, count - buf_pos,
"%s", entry);
- buf_pos += strlen(entry);
+ buf_pos += entry_len;
buf[buf_pos] = '\n';
buf_pos++;
}
- p += strlen(entry) + 1;
+ p += entry_len + 1;
}
mutex_unlock(&map->cache_lock);

--
2.1.3

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