When setting bool values via sysfs interface, e.g. writeback_metadata,
if writing 1 into writeback_metadata file, dc->writeback_metadata is
set to 1, but if writing 2 into the file, dc->writeback_metadata is
0. This is misleading, a better result should be 1 for all non-zero
input value.
It is because dc->writeback_metadata is a bit-field variable, and
current code simply use d_strtoul() to convert a string into integer
and takes the lowest bit value. To fix such error, we need a routine
to convert the input string into unsigned integer, and set target
variable to 1 if the converted integer is non-zero.
This patch introduces a new macro called sysfs_strtoul_bool(), it can
be used to convert input string into bool value, we can use it to set
bool value for bit-field vairables.
Signed-off-by: Coly Li <colyli@xxxxxxx>
---
drivers/md/bcache/sysfs.h | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/md/bcache/sysfs.h b/drivers/md/bcache/sysfs.h
index 0ad2715a884e..215df32f567b 100644
--- a/drivers/md/bcache/sysfs.h
+++ b/drivers/md/bcache/sysfs.h
@@ -79,6 +79,16 @@ do { \
return strtoul_safe(buf, var) ?: (ssize_t) size; \
} while (0)
+#define sysfs_strtoul_bool(file, var) \
+do { \
+ if (attr == &sysfs_ ## file) { \
+ unsigned long v = strtoul_or_return(buf); \
+ \
+ var = v ? 1 : 0; \
+ return size; \
+ } \
+} while (0)
+
#define sysfs_strtoul_clamp(file, var, min, max) \
do { \
if (attr == &sysfs_ ## file) { \
--
2.16.4
