[PATCH 29/32] lib/string_helpers: string_get_size() now returns characters wrote

Kent Overstreet
2023-05-09T17:00:31Z

From: Kent Overstreet <kent.overstreet@gmail.com>

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 the return value of snprintf().

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---
include/linux/string_helpers.h | 4 ++--
lib/string_helpers.c | 8 ++++----
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/string_helpers.h b/include/linux/string_helpers.h
index fae6beaaa2..44148f8feb 100644
--- a/include/linux/string_helpers.h
+++ b/include/linux/string_helpers.h
@@ -23,8 +23,8 @@ 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);

int parse_int_array_user(const char __user *from, size_t count, int **array);

diff --git a/lib/string_helpers.c b/lib/string_helpers.c
index 230020a2e0..ca36ceba0e 100644
--- a/lib/string_helpers.c
+++ b/lib/string_helpers.c
@@ -32,8 +32,8 @@
* 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"
@@ -126,8 +126,8 @@ 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);

--
2.40.1