ftrace: Clean up the recursion code a bit (7b68621f) · Commits · 戴 / test

include/linux/trace_recursion.h

+7 −15

Original line number	Diff line number	Diff line
		@@ -162,7 +162,7 @@ extern void ftrace_record_recursion(unsigned long ip, unsigned long parent_ip);
		static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsigned long pip,
		int start, int max)
		{
		unsigned int val = current->trace_recursion;
		unsigned int val = READ_ONCE(current->trace_recursion);
		int bit;

		/* A previous recursion check was made */
		@@ -176,17 +176,14 @@ static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsign
		* a switch between contexts. Allow for a single recursion.
		*/
		bit = TRACE_TRANSITION_BIT;
		if (trace_recursion_test(bit)) {
		if (val & (1 << bit)) {
		do_ftrace_record_recursion(ip, pip);
		return -1;
		}
		trace_recursion_set(bit);
		barrier();
		return bit + 1;
		}

		} else {
		/* Normal check passed, clear the transition to allow it again */
		trace_recursion_clear(TRACE_TRANSITION_BIT);
		val &= ~(1 << TRACE_TRANSITION_BIT);
		}

		val \|= 1 << bit;
		current->trace_recursion = val;
		@@ -197,17 +194,12 @@ static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsign

		static __always_inline void trace_clear_recursion(int bit)
		{
		unsigned int val = current->trace_recursion;

		if (!bit)
		return;

		bit--;
		bit = 1 << bit;
		val &= ~bit;

		barrier();
		current->trace_recursion = val;
		bit--;
		trace_recursion_clear(bit);
		}

		/**