[PATCH 05/32] lib/string_helpers: string_get_size() now returns characters wrote

From: Kent Overstreet
Date: Sun Aug 14 2022 - 17:21:11 EST


From: Kent Overstreet <kent.overstreet@xxxxxxxxx>

printbuf now needs to know the number of characters that would have been
written if the buffer was too small, like snprintf(); this changes
string_get_size() to return the return value of snprintf().

Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Andy Shevchenko <andy@xxxxxxxxxx>
Acked-by: Andy Shevchenko <andy@xxxxxxxxxx>
---
include/linux/string_helpers.h | 4 ++--
lib/string_helpers.c | 7 +++----
2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index c048eaec08..ae4383f0fe 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -19,8 +19,8 @@ enum string_size_units {
STRING_UNITS_2, /* use binary powers of 2^10 */
};

-void string_get_size(u64 size, u64 blk_size, enum string_size_units units,
- char *buf, int len);
+int string_get_size(u64 size, u64 blk_size, enum string_size_units units,
+ char *buf, int len);

#define UNESCAPE_SPACE BIT(0)
#define UNESCAPE_OCTAL BIT(1)
diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index b366c660e6..a48c6a1cdd 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -33,8 +33,8 @@
* at least 9 bytes and will always be zero terminated.
*
*/
-void string_get_size(u64 size, u64 blk_size, const enum string_size_units units,
- char *buf, int len)
+int string_get_size(u64 size, u64 blk_size, const enum string_size_units units,
+ char *buf, int len)
{
static const char *const units_10[] = {
"B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"
@@ -127,8 +127,7 @@ void string_get_size(u64 size, u64 blk_size, const enum string_size_units units,
else
unit = units_str[units][i];

- snprintf(buf, len, "%u%s %s", (u32)size,
- tmp, unit);
+ return snprintf(buf, len, "%u%s %s", (u32)size, tmp, unit);
}
EXPORT_SYMBOL(string_get_size);

--
2.36.1