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Commit b3a88803 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Steven Rostedt (VMware)
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ftrace: Kill FTRACE_OPS_FL_PER_CPU 

The one and only user of FTRACE_OPS_FL_PER_CPU is gone, remove the
lot.

Link: http://lkml.kernel.org/r/20171011080224.372422809@infradead.org



Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 1dd311e6

include/linux/ftrace.h

+14 −69
Original line number Diff line number Diff line
@@ -102,10 +102,6 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops); 
 * ENABLED - set/unset when ftrace_ops is registered/unregistered

 * DYNAMIC - set when ftrace_ops is registered to denote dynamically

 *           allocated ftrace_ops which need special care

 * PER_CPU - set manualy by ftrace_ops user to denote the ftrace_ops

 *           could be controlled by following calls:

 *             ftrace_function_local_enable

 *             ftrace_function_local_disable

 * SAVE_REGS - The ftrace_ops wants regs saved at each function called

 *            and passed to the callback. If this flag is set, but the

 *            architecture does not support passing regs
@@ -149,21 +145,20 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops); 
enum {

	FTRACE_OPS_FL_ENABLED			= 1 << 0,

	FTRACE_OPS_FL_DYNAMIC			= 1 << 1,

	FTRACE_OPS_FL_PER_CPU			= 1 << 2,

	FTRACE_OPS_FL_SAVE_REGS			= 1 << 3,

	FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED	= 1 << 4,

	FTRACE_OPS_FL_RECURSION_SAFE		= 1 << 5,

	FTRACE_OPS_FL_STUB			= 1 << 6,

	FTRACE_OPS_FL_INITIALIZED		= 1 << 7,

	FTRACE_OPS_FL_DELETED			= 1 << 8,

	FTRACE_OPS_FL_ADDING			= 1 << 9,

	FTRACE_OPS_FL_REMOVING			= 1 << 10,

	FTRACE_OPS_FL_MODIFYING			= 1 << 11,

	FTRACE_OPS_FL_ALLOC_TRAMP		= 1 << 12,

	FTRACE_OPS_FL_IPMODIFY			= 1 << 13,

	FTRACE_OPS_FL_PID			= 1 << 14,

	FTRACE_OPS_FL_RCU			= 1 << 15,

	FTRACE_OPS_FL_TRACE_ARRAY		= 1 << 16,

	FTRACE_OPS_FL_SAVE_REGS			= 1 << 2,

	FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED	= 1 << 3,

	FTRACE_OPS_FL_RECURSION_SAFE		= 1 << 4,

	FTRACE_OPS_FL_STUB			= 1 << 5,

	FTRACE_OPS_FL_INITIALIZED		= 1 << 6,

	FTRACE_OPS_FL_DELETED			= 1 << 7,

	FTRACE_OPS_FL_ADDING			= 1 << 8,

	FTRACE_OPS_FL_REMOVING			= 1 << 9,

	FTRACE_OPS_FL_MODIFYING			= 1 << 10,

	FTRACE_OPS_FL_ALLOC_TRAMP		= 1 << 11,

	FTRACE_OPS_FL_IPMODIFY			= 1 << 12,

	FTRACE_OPS_FL_PID			= 1 << 13,

	FTRACE_OPS_FL_RCU			= 1 << 14,

	FTRACE_OPS_FL_TRACE_ARRAY		= 1 << 15,

};



#ifdef CONFIG_DYNAMIC_FTRACE
@@ -198,7 +193,6 @@ struct ftrace_ops { 
	unsigned long			flags;

	void				*private;

	ftrace_func_t			saved_func;

	int __percpu			*disabled;

#ifdef CONFIG_DYNAMIC_FTRACE

	struct ftrace_ops_hash		local_hash;

	struct ftrace_ops_hash		*func_hash;
@@ -230,55 +224,6 @@ int register_ftrace_function(struct ftrace_ops *ops); 
int unregister_ftrace_function(struct ftrace_ops *ops);

void clear_ftrace_function(void);



/**

 * ftrace_function_local_enable - enable ftrace_ops on current cpu

 *

 * This function enables tracing on current cpu by decreasing

 * the per cpu control variable.

 * It must be called with preemption disabled and only on ftrace_ops

 * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption

 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.

 */

static inline void ftrace_function_local_enable(struct ftrace_ops *ops)

{

	if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))

		return;



	(*this_cpu_ptr(ops->disabled))--;

}



/**

 * ftrace_function_local_disable - disable ftrace_ops on current cpu

 *

 * This function disables tracing on current cpu by increasing

 * the per cpu control variable.

 * It must be called with preemption disabled and only on ftrace_ops

 * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption

 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.

 */

static inline void ftrace_function_local_disable(struct ftrace_ops *ops)

{

	if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))

		return;



	(*this_cpu_ptr(ops->disabled))++;

}



/**

 * ftrace_function_local_disabled - returns ftrace_ops disabled value

 *                                  on current cpu

 *

 * This function returns value of ftrace_ops::disabled on current cpu.

 * It must be called with preemption disabled and only on ftrace_ops

 * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption

 * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.

 */

static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)

{

	WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU));

	return *this_cpu_ptr(ops->disabled);

}



extern void ftrace_stub(unsigned long a0, unsigned long a1,

			struct ftrace_ops *op, struct pt_regs *regs);

kernel/trace/ftrace.c

+6 −49
Original line number Diff line number Diff line
@@ -203,30 +203,6 @@ void clear_ftrace_function(void) 
	ftrace_trace_function = ftrace_stub;

}



static void per_cpu_ops_disable_all(struct ftrace_ops *ops)

{

	int cpu;



	for_each_possible_cpu(cpu)

		*per_cpu_ptr(ops->disabled, cpu) = 1;

}



static int per_cpu_ops_alloc(struct ftrace_ops *ops)

{

	int __percpu *disabled;



	if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))

		return -EINVAL;



	disabled = alloc_percpu(int);

	if (!disabled)

		return -ENOMEM;



	ops->disabled = disabled;

	per_cpu_ops_disable_all(ops);

	return 0;

}



static void ftrace_sync(struct work_struct *work)

{

	/*
@@ -262,8 +238,8 @@ static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops) 
	 * If this is a dynamic, RCU, or per CPU ops, or we force list func,

	 * then it needs to call the list anyway.

	 */

	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |

			  FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)

	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||

	    FTRACE_FORCE_LIST_FUNC)

		return ftrace_ops_list_func;



	return ftrace_ops_get_func(ops);
@@ -422,11 +398,6 @@ static int __register_ftrace_function(struct ftrace_ops *ops) 
	if (!core_kernel_data((unsigned long)ops))

		ops->flags |= FTRACE_OPS_FL_DYNAMIC;



	if (ops->flags & FTRACE_OPS_FL_PER_CPU) {

		if (per_cpu_ops_alloc(ops))

			return -ENOMEM;

	}



	add_ftrace_ops(&ftrace_ops_list, ops);



	/* Always save the function, and reset at unregistering */
@@ -2727,11 +2698,6 @@ void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops) 
{

}



static void per_cpu_ops_free(struct ftrace_ops *ops)

{

	free_percpu(ops->disabled);

}



static void ftrace_startup_enable(int command)

{

	if (saved_ftrace_func != ftrace_trace_function) {
@@ -2833,7 +2799,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) 
		 * not currently active, we can just free them

		 * without synchronizing all CPUs.

		 */

		if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU))

		if (ops->flags & FTRACE_OPS_FL_DYNAMIC)

			goto free_ops;



		return 0;
@@ -2880,7 +2846,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) 
	 * The same goes for freeing the per_cpu data of the per_cpu

	 * ops.

	 */

	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {

	if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {

		/*

		 * We need to do a hard force of sched synchronization.

		 * This is because we use preempt_disable() to do RCU, but
@@ -2903,9 +2869,6 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) 


 free_ops:

		arch_ftrace_trampoline_free(ops);



		if (ops->flags & FTRACE_OPS_FL_PER_CPU)

			per_cpu_ops_free(ops);

	}



	return 0;
@@ -6355,10 +6318,7 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, 
		 * If any of the above fails then the op->func() is not executed.

		 */

		if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&

		    (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||

		     !ftrace_function_local_disabled(op)) &&

		    ftrace_ops_test(op, ip, regs)) {

		    

			if (FTRACE_WARN_ON(!op->func)) {

				pr_warn("op=%p %pS\n", op, op);

				goto out;
@@ -6416,10 +6376,7 @@ static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip, 


	preempt_disable_notrace();



	if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||

	    !ftrace_function_local_disabled(op)) {

	op->func(ip, parent_ip, op, regs);

	}



	preempt_enable_notrace();

	trace_clear_recursion(bit);
@@ -6443,7 +6400,7 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops) 
	 * or does per cpu logic, then we need to call the assist handler.

	 */

	if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||

	    ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))

	    ops->flags & FTRACE_OPS_FL_RCU)

		return ftrace_ops_assist_func;



	return ops->func;