From: Richard Cochran 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 Signed-off-by: Thomas Gleixner Cc: John Stultz --- include/linux/posix-timers.h | 13 +++++++++++++ kernel/posix-timers.c | 2 +- 2 files changed, 14 insertions(+), 1 deletion(-) Index: linux-2.6-tip/include/linux/posix-timers.h =================================================================== --- linux-2.6-tip.orig/include/linux/posix-timers.h +++ linux-2.6-tip/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 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)) Index: linux-2.6-tip/kernel/posix-timers.c =================================================================== --- linux-2.6-tip.orig/kernel/posix-timers.c +++ linux-2.6-tip/kernel/posix-timers.c @@ -477,7 +477,7 @@ static void release_posix_timer(struct k 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/