mainline inclusion from mainline-5.1-rc1 commit e4db37fb69d56d9523bb540bd8e07bf221aa9f6d category: backport
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@suse.de Signed-off-by: Jens Axboe axboe@kernel.dk --- 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) { \