diff options
| author | Richard Cochran <richard.cochran@omicron.at> | 2011-02-01 13:52:32 +0000 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-02-02 15:28:19 +0100 |
| commit | 81e294cba2596f5f10848bbe19d98b344c2a2d5c (patch) | |
| tree | 4334ced22eff475275a81f7e62f1f5e9df43a433 | |
| parent | ce26efdefa5e8f22d933df72d7f7482725091d6d (diff) | |
posix-timers: Add support for fd based clocks
Extend the negative clockids which are currently used by posix cpu
timers to encode the PID with a file descriptor based type which
encodes the fd in the upper bits.
Originally-from: Richard Cochran <richard.cochran@omicron.at>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <johnstul@us.ibm.com>
LKML-Reference: <20110201134420.062860200@linutronix.de>
| -rw-r--r-- | include/linux/posix-timers.h | 13 | ||||
| -rw-r--r-- | kernel/posix-timers.c | 2 |
2 files changed, 14 insertions, 1 deletions
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index 79a1cea7f6ed..88b9256169f8 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -18,6 +18,17 @@ struct cpu_timer_list { int firing; }; +/* + * Bit fields within a clockid: + * + * The most significant 29 bits hold either a pid or a file descriptor. + * + * Bit 2 indicates whether a cpu clock refers to a thread or a process. + * + * Bits 1 and 0 give the type: PROF=0, VIRT=1, SCHED=2, or FD=3. + * + * A clockid is invalid if bits 2, 1, and 0 are all set. + */ #define CPUCLOCK_PID(clock) ((pid_t) ~((clock) >> 3)) #define CPUCLOCK_PERTHREAD(clock) \ (((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0) @@ -29,6 +40,8 @@ struct cpu_timer_list { #define CPUCLOCK_VIRT 1 #define CPUCLOCK_SCHED 2 #define CPUCLOCK_MAX 3 +#define CLOCKFD CPUCLOCK_MAX +#define CLOCKFD_MASK (CPUCLOCK_PERTHREAD_MASK|CPUCLOCK_CLOCK_MASK) #define MAKE_PROCESS_CPUCLOCK(pid, clock) \ ((~(clockid_t) (pid) << 3) | (clockid_t) (clock)) diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index 5a5a4f1c0971..df629d853a81 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -488,7 +488,7 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set) static struct k_clock *clockid_to_kclock(const clockid_t id) { if (id < 0) - return &clock_posix_cpu; + return (id & CLOCKFD_MASK) == CLOCKFD ? NULL : &clock_posix_cpu; if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres) return NULL; |