On 7/20/22 18:41, Steven Rostedt wrote: > On Tue, 19 Jul 2022 19:27:07 +0200 > Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> wrote: > >> +/* >> + * reacting_on interface. >> + */ >> +static ssize_t reacting_on_read_data(struct file *filp, >> + char __user *user_buf, >> + size_t count, loff_t *ppos) >> +{ >> + char *buff; >> + >> + mutex_lock(&rv_interface_lock); >> + buff = reacting_on ? "1\n" : "0\n"; >> + mutex_unlock(&rv_interface_lock); > Again, no need for the locks, but perhaps just to keep things sane: > > buf = READ_ONCE(reacting_on) ? "1\n" : "0\n"; So, for all files that only read/write a single variable, use READ_ONCE/WRITE_ONCE without locks? (and in all usage of that variable too). -- Daniel > -- Steve >