Re: [PATCH v6 19/22] x86/resctrl: Introduce the interface to switch between monitor modes

[Moger, Babu]

Hi Reinette,

On 8/16/24 16:42, Reinette Chatre wrote:
> Hi Babu,
> 
> On 8/6/24 3:00 PM, Babu Moger wrote:
>> +static ssize_t rdtgroup_mbm_mode_write(struct kernfs_open_file *of,
>> +                       char *buf, size_t nbytes,
>> +                       loff_t off)
>> +{
>> +    int mbm_cntr_assign = resctrl_arch_get_abmc_enabled();
> 
> This needs to be protected by the mutex.

Agree.. Will do.

> 
>> +    struct rdt_resource *r = of->kn->parent->priv;
>> +    int ret = 0;
>> +
>> +    /* Valid input requires a trailing newline */
>> +    if (nbytes == 0 || buf[nbytes - 1] != '\n')
>> +        return -EINVAL;
>> +
>> +    buf[nbytes - 1] = '\0';
>> +
>> +    cpus_read_lock();
>> +    mutex_lock(&rdtgroup_mutex);
>> +
>> +    rdt_last_cmd_clear();
>> +
>> +    if (!strcmp(buf, "legacy")) {
>> +        if (mbm_cntr_assign)
>> +            resctrl_arch_mbm_cntr_assign_disable();
>> +    } else if (!strcmp(buf, "mbm_cntr_assign")) {
>> +        if (!mbm_cntr_assign) {
>> +            rdtgroup_mbm_cntr_reset(r);
>> +            ret = resctrl_arch_mbm_cntr_assign_enable();
>> +        }
>> +    } else {
>> +        ret = -EINVAL;
>> +    }
>> +
>> +    mutex_unlock(&rdtgroup_mutex);
>> +    cpus_read_unlock();
>> +
>> +    return ret ?: nbytes;
>> +}
>> +
> 
> Reinette
> 

-- 
Thanks
Babu Moger