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bcache: add sysfs_strtoul_bool() for setting bit-field variables

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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>
This commit is contained in:
Coly Li 2019-02-09 12:53:02 +08:00 committed by Jens Axboe
parent 8c27a3953e
commit e4db37fb69
1 changed files with 10 additions and 0 deletions
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10
drivers/md/bcache/sysfs.h
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@ -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) { \