On 6/8/21 9:40 PM, Damien Le Moal wrote:
> On 2021/06/09 8:07, Bart Van Assche wrote:
[ ... ]
>> +/*
>> + * The accepted I/O priority values are 0..IOPRIO_CLASS_MAX(3). 0 (default)
>> + * means do not modify the I/O priority. Values 1..3 are used to restrict the
>> + * I/O priority for a cgroup to the specified priority. See also
>> + * <linux/ioprio.h>.
>> + */
>> +#define IOPRIO_CLASS_MAX IOPRIO_CLASS_IDLE
[ ... ]
>> +static int ioprio_set_prio_class(struct cgroup_subsys_state *css,
>> + struct cftype *cft, u64 val)
>> +{
>> + struct ioprio_blkcg *blkcg = ioprio_blkcg_from_css(css);
>> +
>> + if (val > IOPRIO_CLASS_MAX)
>> + return -EINVAL;
>
> Where is IOPRIO_CLASS_MAX defined ? I do not see it.
Near the start of the new block/blk-ioprio.c file.
> Why not use ioprio_valid() ?
The definition of that macro is as follows:
#define ioprio_valid(mask) \
(IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)
So that macro accepts I/O priority classes 1..7 while the above code
accepts I/O priority classes 0..3. I think that ioprio_set_prio_class()
should only accept I/O priority class values 0..3.
Thanks,
Bart.
