diff options
Diffstat (limited to 'include/linux/timer.h')
| -rw-r--r-- | include/linux/timer.h | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/include/linux/timer.h b/include/linux/timer.h index 3f95c1fa615..8c5a197e158 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -49,18 +49,26 @@ extern struct tvec_base boot_tvec_bases; #endif /* - * Note that all tvec_bases are 2 byte aligned and lower bit of - * base in timer_list is guaranteed to be zero. Use the LSB to - * indicate whether the timer is deferrable. + * Note that all tvec_bases are at least 4 byte aligned and lower two bits + * of base in timer_list is guaranteed to be zero. Use them for flags. * * A deferrable timer will work normally when the system is busy, but * will not cause a CPU to come out of idle just to service it; instead, * the timer will be serviced when the CPU eventually wakes up with a * subsequent non-deferrable timer. + * + * An irqsafe timer is executed with IRQ disabled and it's safe to wait for + * the completion of the running instance from IRQ handlers, for example, + * by calling del_timer_sync(). + * + * Note: The irq disabled callback execution is a special case for + * workqueue locking issues. It's not meant for executing random crap + * with interrupts disabled. Abuse is monitored! */ #define TIMER_DEFERRABLE 0x1LU +#define TIMER_IRQSAFE 0x2LU -#define TIMER_FLAG_MASK 0x1LU +#define TIMER_FLAG_MASK 0x3LU #define __TIMER_INITIALIZER(_function, _expires, _data, _flags) { \ .entry = { .prev = TIMER_ENTRY_STATIC }, \ |