clocksource: Add module refcount (09ac369c) · Commits · 戴 / test

include/linux/clocksource.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -21,6 +21,7 @@
		/* clocksource cycle base type */
		typedef u64 cycle_t;
		struct clocksource;
		struct module;

		#ifdef CONFIG_ARCH_CLOCKSOURCE_DATA
		#include <asm/clocksource.h>
		@@ -162,6 +163,7 @@ extern u64 timecounter_cyc2time(struct timecounter *tc,
		* @suspend: suspend function for the clocksource, if necessary
		* @resume: resume function for the clocksource, if necessary
		* @cycle_last: most recent cycle counter value seen by ::read()
		* @owner: module reference, must be set by clocksource in modules
		*/
		struct clocksource {
		/*
		@@ -195,6 +197,7 @@ struct clocksource {
		cycle_t cs_last;
		cycle_t wd_last;
		#endif
		struct module *owner;
		} ____cacheline_aligned;

		/*

+14 −5

Original line number	Diff line number	Diff line
		@@ -627,11 +627,20 @@ static int change_clocksource(void *data)
		write_seqcount_begin(&timekeeper_seq);

		timekeeping_forward_now(tk);
		/*
		* If the cs is in module, get a module reference. Succeeds
		* for built-in code (owner == NULL) as well.
		*/
		if (try_module_get(new->owner)) {
		if (!new->enable \|\| new->enable(new) == 0) {
		old = tk->clock;
		tk_setup_internals(tk, new);
		if (old->disable)
		old->disable(old);
		module_put(old->owner);
		} else {
		module_put(new->owner);
		}
		}
		timekeeping_update(tk, true, true);