posix-cpu-timers: Create a container struct

Per task/process data of posix CPU timers is all over the place which
makes the code hard to follow and requires ifdeffery.

Create a container to hold all this information in one place, so data is
consolidated and the ifdeffery can be confined to the posix timer header
file and removed from places like fork.

As a first step, move the cpu_timers list head array into the new struct
and clean up the initializers and simplify fork. The remaining #ifdef in
fork will be removed later.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.819418976@linutronix.de

1 files changed, 34 insertions, 0 deletions

diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 033374b99767..cdef89750b2c 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -62,6 +62,40 @@ static inline int clockid_to_fd(const clockid_t clk)
 	return ~(clk >> 3);
 }
 
+#ifdef CONFIG_POSIX_TIMERS
+/**
+ * posix_cputimers - Container for posix CPU timer related data
+ * @cpu_timers:		List heads to queue posix CPU timers
+ *
+ * Used in task_struct and signal_struct
+ */
+struct posix_cputimers {
+	struct list_head	cpu_timers[CPUCLOCK_MAX];
+};
+
+static inline void posix_cputimers_init(struct posix_cputimers *pct)
+{
+	INIT_LIST_HEAD(&pct->cpu_timers[0]);
+	INIT_LIST_HEAD(&pct->cpu_timers[1]);
+	INIT_LIST_HEAD(&pct->cpu_timers[2]);
+}
+
+/* Init task static initializer */
+#define INIT_CPU_TIMERLISTS(c)	{					\
+	LIST_HEAD_INIT(c.cpu_timers[0]),				\
+	LIST_HEAD_INIT(c.cpu_timers[1]),				\
+	LIST_HEAD_INIT(c.cpu_timers[2]),				\
+}
+
+#define INIT_CPU_TIMERS(s)						\
+	.posix_cputimers = {						\
+		.cpu_timers = INIT_CPU_TIMERLISTS(s.posix_cputimers),	\
+	},
+#else
+struct posix_cputimers { };
+#define INIT_CPU_TIMERS(s)
+#endif
+
 #define REQUEUE_PENDING 1
 
 /**