On Sat, 2017-09-02 at 01:37 +0800, weiping zhang wrote: > 2017-09-02 1:14 GMT+08:00 Paolo Valente <paolo.valente@xxxxxxxxxx>: > > Il giorno 30 ago 2017, alle ore 20:42, Bart Van Assche <bart.vanassche@xxxxxxx> ha scritto: > > > > > > Make sysfs writes fail for invalid numbers instead of storing > > > uninitialized data copied from the stack. This patch removes > > > all uninitialized_var() occurrences from the BFQ source code. > > > > > > Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx> > > > Cc: Paolo Valente <paolo.valente@xxxxxxxxxx> > > > > Acked-by: Paolo Valente <paolo.valente@xxxxxxxxxx> > > how about using simple_strtoul which was used in cfq/mq-iosched.c > *var = simple_strtoul(p, &p, 10); > > if invalid string came from sysfs, this function just return 0, > and there are validations after every calling bfq_var_store. Hello Weiping, Sorry but I do not like this proposal because: * If invalid input is provided writing into a sysfs attribute should fail instead of ignoring the invalid input silently. * simple_strtoul() is considered obsolete and must not be used in new code. From include/linux/kernel.h: /* Obsolete, do not use. Use kstrto<foo> instead */ extern unsigned long simple_strtoul(const char *,char **,unsigned int); extern long simple_strtol(const char *,char **,unsigned int); extern unsigned long long simple_strtoull(const char *,char **,unsigned int); extern long long simple_strtoll(const char *,char **,unsigned int); Bart.
