tracing: Move snapshot code out of trace.c and into trace_snapshot.c

The trace.c file was a dumping ground for most tracing code. Start
organizing it better by moving various functions out into their own files.
Move all the snapshot code, including the max trace code into its own
trace_snapshot.c file.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260324140145.36352d6a@gandalf.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

4 files changed, 1188 insertions, 1177 deletions

diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 04096c21d06b..83aeb5c77008 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_TRACING) += trace_seq.o
 obj-$(CONFIG_TRACING) += trace_stat.o
 obj-$(CONFIG_TRACING) += trace_printk.o
 obj-$(CONFIG_TRACING) += trace_pid.o
+obj-$(CONFIG_TRACER_SNAPSHOT) += trace_snapshot.o
 obj-$(CONFIG_TRACING) += 	pid_list.o
 obj-$(CONFIG_TRACING_MAP) += tracing_map.o
 obj-$(CONFIG_PREEMPTIRQ_DELAY_TEST) += preemptirq_delay_test.o
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index cf48fe23e71f..850f62032fd2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -47,7 +47,6 @@
 #include <linux/trace.h>
 #include <linux/sched/clock.h>
 #include <linux/sched/rt.h>
-#include <linux/fsnotify.h>
 #include <linux/irq_work.h>
 #include <linux/workqueue.h>
 #include <linux/sort.h>
@@ -219,15 +218,9 @@ static void ftrace_trace_userstack(struct trace_array *tr,
 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
 static char *default_bootup_tracer;
 
-static bool allocate_snapshot;
-static bool snapshot_at_boot;
-
 static char boot_instance_info[COMMAND_LINE_SIZE] __initdata;
 static int boot_instance_index;
 
-static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata;
-static int boot_snapshot_index;
-
 static int __init set_cmdline_ftrace(char *str)
 {
 	strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
@@ -276,38 +269,6 @@ static int __init stop_trace_on_warning(char *str)
 }
 __setup("traceoff_on_warning", stop_trace_on_warning);
 
-static int __init boot_alloc_snapshot(char *str)
-{
-	char *slot = boot_snapshot_info + boot_snapshot_index;
-	int left = sizeof(boot_snapshot_info) - boot_snapshot_index;
-	int ret;
-
-	if (str[0] == '=') {
-		str++;
-		if (strlen(str) >= left)
-			return -1;
-
-		ret = snprintf(slot, left, "%s\t", str);
-		boot_snapshot_index += ret;
-	} else {
-		allocate_snapshot = true;
-		/* We also need the main ring buffer expanded */
-		trace_set_ring_buffer_expanded(NULL);
-	}
-	return 1;
-}
-__setup("alloc_snapshot", boot_alloc_snapshot);
-
-
-static int __init boot_snapshot(char *str)
-{
-	snapshot_at_boot = true;
-	boot_alloc_snapshot(str);
-	return 1;
-}
-__setup("ftrace_boot_snapshot", boot_snapshot);
-
-
 static int __init boot_instance(char *str)
 {
 	char *slot = boot_instance_info + boot_instance_index;
@@ -807,47 +768,6 @@ void tracing_on(void)
 EXPORT_SYMBOL_GPL(tracing_on);
 
 #ifdef CONFIG_TRACER_SNAPSHOT
-static void tracing_snapshot_instance_cond(struct trace_array *tr,
-					   void *cond_data)
-{
-	unsigned long flags;
-
-	if (in_nmi()) {
-		trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
-		trace_array_puts(tr, "*** snapshot is being ignored        ***\n");
-		return;
-	}
-
-	if (!tr->allocated_snapshot) {
-		trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n");
-		trace_array_puts(tr, "*** stopping trace here!   ***\n");
-		tracer_tracing_off(tr);
-		return;
-	}
-
-	if (tr->mapped) {
-		trace_array_puts(tr, "*** BUFFER MEMORY MAPPED ***\n");
-		trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
-		return;
-	}
-
-	/* Note, snapshot can not be used when the tracer uses it */
-	if (tracer_uses_snapshot(tr->current_trace)) {
-		trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n");
-		trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
-		return;
-	}
-
-	local_irq_save(flags);
-	update_max_tr(tr, current, smp_processor_id(), cond_data);
-	local_irq_restore(flags);
-}
-
-void tracing_snapshot_instance(struct trace_array *tr)
-{
-	tracing_snapshot_instance_cond(tr, NULL);
-}
-
 /**
  * tracing_snapshot - take a snapshot of the current buffer.
  *
@@ -871,138 +791,6 @@ void tracing_snapshot(void)
 EXPORT_SYMBOL_GPL(tracing_snapshot);
 
 /**
- * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
- * @tr:		The tracing instance to snapshot
- * @cond_data:	The data to be tested conditionally, and possibly saved
- *
- * This is the same as tracing_snapshot() except that the snapshot is
- * conditional - the snapshot will only happen if the
- * cond_snapshot.update() implementation receiving the cond_data
- * returns true, which means that the trace array's cond_snapshot
- * update() operation used the cond_data to determine whether the
- * snapshot should be taken, and if it was, presumably saved it along
- * with the snapshot.
- */
-void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
-{
-	tracing_snapshot_instance_cond(tr, cond_data);
-}
-EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
-
-/**
- * tracing_cond_snapshot_data - get the user data associated with a snapshot
- * @tr:		The tracing instance
- *
- * When the user enables a conditional snapshot using
- * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
- * with the snapshot.  This accessor is used to retrieve it.
- *
- * Should not be called from cond_snapshot.update(), since it takes
- * the tr->max_lock lock, which the code calling
- * cond_snapshot.update() has already done.
- *
- * Returns the cond_data associated with the trace array's snapshot.
- */
-void *tracing_cond_snapshot_data(struct trace_array *tr)
-{
-	void *cond_data = NULL;
-
-	local_irq_disable();
-	arch_spin_lock(&tr->max_lock);
-
-	if (tr->cond_snapshot)
-		cond_data = tr->cond_snapshot->cond_data;
-
-	arch_spin_unlock(&tr->max_lock);
-	local_irq_enable();
-
-	return cond_data;
-}
-EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
-
-static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
-					struct array_buffer *size_buf, int cpu_id);
-static void set_buffer_entries(struct array_buffer *buf, unsigned long val);
-
-int tracing_alloc_snapshot_instance(struct trace_array *tr)
-{
-	int order;
-	int ret;
-
-	if (!tr->allocated_snapshot) {
-
-		/* Make the snapshot buffer have the same order as main buffer */
-		order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
-		ret = ring_buffer_subbuf_order_set(tr->snapshot_buffer.buffer, order);
-		if (ret < 0)
-			return ret;
-
-		/* allocate spare buffer */
-		ret = resize_buffer_duplicate_size(&tr->snapshot_buffer,
-				   &tr->array_buffer, RING_BUFFER_ALL_CPUS);
-		if (ret < 0)
-			return ret;
-
-		tr->allocated_snapshot = true;
-	}
-
-	return 0;
-}
-
-static void free_snapshot(struct trace_array *tr)
-{
-	/*
-	 * We don't free the ring buffer. instead, resize it because
-	 * The max_tr ring buffer has some state (e.g. ring->clock) and
-	 * we want preserve it.
-	 */
-	ring_buffer_subbuf_order_set(tr->snapshot_buffer.buffer, 0);
-	ring_buffer_resize(tr->snapshot_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
-	set_buffer_entries(&tr->snapshot_buffer, 1);
-	tracing_reset_online_cpus(&tr->snapshot_buffer);
-	tr->allocated_snapshot = false;
-}
-
-static int tracing_arm_snapshot_locked(struct trace_array *tr)
-{
-	int ret;
-
-	lockdep_assert_held(&trace_types_lock);
-
-	spin_lock(&tr->snapshot_trigger_lock);
-	if (tr->snapshot == UINT_MAX || tr->mapped) {
-		spin_unlock(&tr->snapshot_trigger_lock);
-		return -EBUSY;
-	}
-
-	tr->snapshot++;
-	spin_unlock(&tr->snapshot_trigger_lock);
-
-	ret = tracing_alloc_snapshot_instance(tr);
-	if (ret) {
-		spin_lock(&tr->snapshot_trigger_lock);
-		tr->snapshot--;
-		spin_unlock(&tr->snapshot_trigger_lock);
-	}
-
-	return ret;
-}
-
-int tracing_arm_snapshot(struct trace_array *tr)
-{
-	guard(mutex)(&trace_types_lock);
-	return tracing_arm_snapshot_locked(tr);
-}
-
-void tracing_disarm_snapshot(struct trace_array *tr)
-{
-	spin_lock(&tr->snapshot_trigger_lock);
-	if (!WARN_ON(!tr->snapshot))
-		tr->snapshot--;
-	spin_unlock(&tr->snapshot_trigger_lock);
-}
-
-/**
  * tracing_alloc_snapshot - allocate snapshot buffer.
  *
  * This only allocates the snapshot buffer if it isn't already
@@ -1023,129 +811,12 @@ int tracing_alloc_snapshot(void)
 	return ret;
 }
 EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
-
-/**
- * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
- *
- * This is similar to tracing_snapshot(), but it will allocate the
- * snapshot buffer if it isn't already allocated. Use this only
- * where it is safe to sleep, as the allocation may sleep.
- *
- * This causes a swap between the snapshot buffer and the current live
- * tracing buffer. You can use this to take snapshots of the live
- * trace when some condition is triggered, but continue to trace.
- */
-void tracing_snapshot_alloc(void)
-{
-	int ret;
-
-	ret = tracing_alloc_snapshot();
-	if (ret < 0)
-		return;
-
-	tracing_snapshot();
-}
-EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
-
-/**
- * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
- * @tr:		The tracing instance
- * @cond_data:	User data to associate with the snapshot
- * @update:	Implementation of the cond_snapshot update function
- *
- * Check whether the conditional snapshot for the given instance has
- * already been enabled, or if the current tracer is already using a
- * snapshot; if so, return -EBUSY, else create a cond_snapshot and
- * save the cond_data and update function inside.
- *
- * Returns 0 if successful, error otherwise.
- */
-int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
-				 cond_update_fn_t update)
-{
-	struct cond_snapshot *cond_snapshot __free(kfree) =
-		kzalloc_obj(*cond_snapshot);
-	int ret;
-
-	if (!cond_snapshot)
-		return -ENOMEM;
-
-	cond_snapshot->cond_data = cond_data;
-	cond_snapshot->update = update;
-
-	guard(mutex)(&trace_types_lock);
-
-	if (tracer_uses_snapshot(tr->current_trace))
-		return -EBUSY;
-
-	/*
-	 * The cond_snapshot can only change to NULL without the
-	 * trace_types_lock. We don't care if we race with it going
-	 * to NULL, but we want to make sure that it's not set to
-	 * something other than NULL when we get here, which we can
-	 * do safely with only holding the trace_types_lock and not
-	 * having to take the max_lock.
-	 */
-	if (tr->cond_snapshot)
-		return -EBUSY;
-
-	ret = tracing_arm_snapshot_locked(tr);
-	if (ret)
-		return ret;
-
-	local_irq_disable();
-	arch_spin_lock(&tr->max_lock);
-	tr->cond_snapshot = no_free_ptr(cond_snapshot);
-	arch_spin_unlock(&tr->max_lock);
-	local_irq_enable();
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
-
-/**
- * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
- * @tr:		The tracing instance
- *
- * Check whether the conditional snapshot for the given instance is
- * enabled; if so, free the cond_snapshot associated with it,
- * otherwise return -EINVAL.
- *
- * Returns 0 if successful, error otherwise.
- */
-int tracing_snapshot_cond_disable(struct trace_array *tr)
-{
-	int ret = 0;
-
-	local_irq_disable();
-	arch_spin_lock(&tr->max_lock);
-
-	if (!tr->cond_snapshot)
-		ret = -EINVAL;
-	else {
-		kfree(tr->cond_snapshot);
-		tr->cond_snapshot = NULL;
-	}
-
-	arch_spin_unlock(&tr->max_lock);
-	local_irq_enable();
-
-	tracing_disarm_snapshot(tr);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
 #else
 void tracing_snapshot(void)
 {
 	WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
 }
 EXPORT_SYMBOL_GPL(tracing_snapshot);
-void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
-{
-	WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
-}
-EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
 int tracing_alloc_snapshot(void)
 {
 	WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
@@ -1158,23 +829,6 @@ void tracing_snapshot_alloc(void)
 	tracing_snapshot();
 }
 EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
-void *tracing_cond_snapshot_data(struct trace_array *tr)
-{
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
-int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
-{
-	return -ENODEV;
-}
-EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
-int tracing_snapshot_cond_disable(struct trace_array *tr)
-{
-	return false;
-}
-EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
-#define free_snapshot(tr)	do { } while (0)
-#define tracing_arm_snapshot_locked(tr) ({ -EBUSY; })
 #endif /* CONFIG_TRACER_SNAPSHOT */
 
 void tracer_tracing_off(struct trace_array *tr)
@@ -1487,206 +1141,6 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
 
 unsigned long __read_mostly	tracing_thresh;
 
-#ifdef CONFIG_TRACER_MAX_TRACE
-#ifdef LATENCY_FS_NOTIFY
-static struct workqueue_struct *fsnotify_wq;
-
-static void latency_fsnotify_workfn(struct work_struct *work)
-{
-	struct trace_array *tr = container_of(work, struct trace_array,
-					      fsnotify_work);
-	fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY);
-}
-
-static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
-{
-	struct trace_array *tr = container_of(iwork, struct trace_array,
-					      fsnotify_irqwork);
-	queue_work(fsnotify_wq, &tr->fsnotify_work);
-}
-
-__init static int latency_fsnotify_init(void)
-{
-	fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
-				      WQ_UNBOUND | WQ_HIGHPRI, 0);
-	if (!fsnotify_wq) {
-		pr_err("Unable to allocate tr_max_lat_wq\n");
-		return -ENOMEM;
-	}
-	return 0;
-}
-
-late_initcall_sync(latency_fsnotify_init);
-
-void latency_fsnotify(struct trace_array *tr)
-{
-	if (!fsnotify_wq)
-		return;
-	/*
-	 * We cannot call queue_work(&tr->fsnotify_work) from here because it's
-	 * possible that we are called from __schedule() or do_idle(), which
-	 * could cause a deadlock.
-	 */
-	irq_work_queue(&tr->fsnotify_irqwork);
-}
-#endif /* !LATENCY_FS_NOTIFY */
-
-static const struct file_operations tracing_max_lat_fops;
-
-static void trace_create_maxlat_file(struct trace_array *tr,
-				     struct dentry *d_tracer)
-{
-#ifdef LATENCY_FS_NOTIFY
-	INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
-	init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
-#endif
-	tr->d_max_latency = trace_create_file("tracing_max_latency",
-					      TRACE_MODE_WRITE,
-					      d_tracer, tr,
-					      &tracing_max_lat_fops);
-}
-
-/*
- * Copy the new maximum trace into the separate maximum-trace
- * structure. (this way the maximum trace is permanently saved,
- * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
- */
-static void
-__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
-{
-	struct array_buffer *trace_buf = &tr->array_buffer;
-	struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
-	struct array_buffer *max_buf = &tr->snapshot_buffer;
-	struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
-
-	max_buf->cpu = cpu;
-	max_buf->time_start = data->preempt_timestamp;
-
-	max_data->saved_latency = tr->max_latency;
-	max_data->critical_start = data->critical_start;
-	max_data->critical_end = data->critical_end;
-
-	strscpy(max_data->comm, tsk->comm);
-	max_data->pid = tsk->pid;
-	/*
-	 * If tsk == current, then use current_uid(), as that does not use
-	 * RCU. The irq tracer can be called out of RCU scope.
-	 */
-	if (tsk == current)
-		max_data->uid = current_uid();
-	else
-		max_data->uid = task_uid(tsk);
-
-	max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
-	max_data->policy = tsk->policy;
-	max_data->rt_priority = tsk->rt_priority;
-
-	/* record this tasks comm */
-	tracing_record_cmdline(tsk);
-	latency_fsnotify(tr);
-}
-#else
-static inline void trace_create_maxlat_file(struct trace_array *tr,
-					    struct dentry *d_tracer) { }
-static inline void __update_max_tr(struct trace_array *tr,
-				   struct task_struct *tsk, int cpu) { }
-#endif /* CONFIG_TRACER_MAX_TRACE */
-
-#ifdef CONFIG_TRACER_SNAPSHOT
-/**
- * update_max_tr - snapshot all trace buffers from global_trace to max_tr
- * @tr: tracer
- * @tsk: the task with the latency
- * @cpu: The cpu that initiated the trace.
- * @cond_data: User data associated with a conditional snapshot
- *
- * Flip the buffers between the @tr and the max_tr and record information
- * about which task was the cause of this latency.
- */
-void
-update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
-	      void *cond_data)
-{
-	if (tr->stop_count)
-		return;
-
-	WARN_ON_ONCE(!irqs_disabled());
-
-	if (!tr->allocated_snapshot) {
-		/* Only the nop tracer should hit this when disabling */
-		WARN_ON_ONCE(tr->current_trace != &nop_trace);
-		return;
-	}
-
-	arch_spin_lock(&tr->max_lock);
-
-	/* Inherit the recordable setting from array_buffer */
-	if (ring_buffer_record_is_set_on(tr->array_buffer.buffer))
-		ring_buffer_record_on(tr->snapshot_buffer.buffer);
-	else
-		ring_buffer_record_off(tr->snapshot_buffer.buffer);
-
-	if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data)) {
-		arch_spin_unlock(&tr->max_lock);
-		return;
-	}
-
-	swap(tr->array_buffer.buffer, tr->snapshot_buffer.buffer);
-
-	__update_max_tr(tr, tsk, cpu);
-
-	arch_spin_unlock(&tr->max_lock);
-
-	/* Any waiters on the old snapshot buffer need to wake up */
-	ring_buffer_wake_waiters(tr->array_buffer.buffer, RING_BUFFER_ALL_CPUS);
-}
-
-/**
- * update_max_tr_single - only copy one trace over, and reset the rest
- * @tr: tracer
- * @tsk: task with the latency
- * @cpu: the cpu of the buffer to copy.
- *
- * Flip the trace of a single CPU buffer between the @tr and the max_tr.
- */
-void
-update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
-{
-	int ret;
-
-	if (tr->stop_count)
-		return;
-
-	WARN_ON_ONCE(!irqs_disabled());
-	if (!tr->allocated_snapshot) {
-		/* Only the nop tracer should hit this when disabling */
-		WARN_ON_ONCE(tr->current_trace != &nop_trace);
-		return;
-	}
-
-	arch_spin_lock(&tr->max_lock);
-
-	ret = ring_buffer_swap_cpu(tr->snapshot_buffer.buffer, tr->array_buffer.buffer, cpu);
-
-	if (ret == -EBUSY) {
-		/*
-		 * We failed to swap the buffer due to a commit taking
-		 * place on this CPU. We fail to record, but we reset
-		 * the max trace buffer (no one writes directly to it)
-		 * and flag that it failed.
-		 * Another reason is resize is in progress.
-		 */
-		trace_array_printk_buf(tr->snapshot_buffer.buffer, _THIS_IP_,
-			"Failed to swap buffers due to commit or resize in progress\n");
-	}
-
-	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
-
-	__update_max_tr(tr, tsk, cpu);
-	arch_spin_unlock(&tr->max_lock);
-}
-#endif /* CONFIG_TRACER_SNAPSHOT */
-
 struct pipe_wait {
 	struct trace_iterator		*iter;
 	int				wait_index;
@@ -1995,7 +1449,7 @@ int __init register_tracer(struct tracer *type)
 	return 0;
 }
 
-static void tracing_reset_cpu(struct array_buffer *buf, int cpu)
+void tracing_reset_cpu(struct array_buffer *buf, int cpu)
 {
 	struct trace_buffer *buffer = buf->buffer;
 
@@ -3760,50 +3214,6 @@ static void test_ftrace_alive(struct seq_file *m)
 		    "#          MAY BE MISSING FUNCTION EVENTS\n");
 }
 
-#ifdef CONFIG_TRACER_SNAPSHOT
-static void show_snapshot_main_help(struct seq_file *m)
-{
-	seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
-		    "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
-		    "#                      Takes a snapshot of the main buffer.\n"
-		    "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
-		    "#                      (Doesn't have to be '2' works with any number that\n"
-		    "#                       is not a '0' or '1')\n");
-}
-
-static void show_snapshot_percpu_help(struct seq_file *m)
-{
-	seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
-#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
-	seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
-		    "#                      Takes a snapshot of the main buffer for this cpu.\n");
-#else
-	seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
-		    "#                     Must use main snapshot file to allocate.\n");
-#endif
-	seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
-		    "#                      (Doesn't have to be '2' works with any number that\n"
-		    "#                       is not a '0' or '1')\n");
-}
-
-static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
-{
-	if (iter->tr->allocated_snapshot)
-		seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
-	else
-		seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
-
-	seq_puts(m, "# Snapshot commands:\n");
-	if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
-		show_snapshot_main_help(m);
-	else
-		show_snapshot_percpu_help(m);
-}
-#else
-/* Should never be called */
-static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
-#endif
-
 static int s_show(struct seq_file *m, void *v)
 {
 	struct trace_iterator *iter = v;
@@ -3852,17 +3262,6 @@ static int s_show(struct seq_file *m, void *v)
 	return 0;
 }
 
-/*
- * Should be used after trace_array_get(), trace_types_lock
- * ensures that i_cdev was already initialized.
- */
-static inline int tracing_get_cpu(struct inode *inode)
-{
-	if (inode->i_cdev) /* See trace_create_cpu_file() */
-		return (long)inode->i_cdev - 1;
-	return RING_BUFFER_ALL_CPUS;
-}
-
 static const struct seq_operations tracer_seq_ops = {
 	.start		= s_start,
 	.next		= s_next,
@@ -3889,7 +3288,7 @@ static void free_trace_iter_content(struct trace_iterator *iter)
 	free_cpumask_var(iter->started);
 }
 
-static struct trace_iterator *
+struct trace_iterator *
 __tracing_open(struct inode *inode, struct file *file, bool snapshot)
 {
 	struct trace_array *tr = inode->i_private;
@@ -4069,7 +3468,7 @@ int tracing_single_release_file_tr(struct inode *inode, struct file *filp)
 	return single_release(inode, filp);
 }
 
-static int tracing_release(struct inode *inode, struct file *file)
+int tracing_release(struct inode *inode, struct file *file)
 {
 	struct trace_array *tr = inode->i_private;
 	struct seq_file *m = file->private_data;
@@ -5220,7 +4619,7 @@ int tracer_init(struct tracer *t, struct trace_array *tr)
 	return t->init(tr);
 }
 
-static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
+void trace_set_buffer_entries(struct array_buffer *buf, unsigned long val)
 {
 	int cpu;
 
@@ -5231,40 +4630,12 @@ static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
 static void update_buffer_entries(struct array_buffer *buf, int cpu)
 {
 	if (cpu == RING_BUFFER_ALL_CPUS) {
-		set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0));
+		trace_set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0));
 	} else {
 		per_cpu_ptr(buf->data, cpu)->entries = ring_buffer_size(buf->buffer, cpu);
 	}
 }
 
-#ifdef CONFIG_TRACER_SNAPSHOT
-/* resize @tr's buffer to the size of @size_tr's entries */
-static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
-					struct array_buffer *size_buf, int cpu_id)
-{
-	int cpu, ret = 0;
-
-	if (cpu_id == RING_BUFFER_ALL_CPUS) {
-		for_each_tracing_cpu(cpu) {
-			ret = ring_buffer_resize(trace_buf->buffer,
-				 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
-			if (ret < 0)
-				break;
-			per_cpu_ptr(trace_buf->data, cpu)->entries =
-				per_cpu_ptr(size_buf->data, cpu)->entries;
-		}
-	} else {
-		ret = ring_buffer_resize(trace_buf->buffer,
-				 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
-		if (ret == 0)
-			per_cpu_ptr(trace_buf->data, cpu_id)->entries =
-				per_cpu_ptr(size_buf->data, cpu_id)->entries;
-	}
-
-	return ret;
-}
-#endif /* CONFIG_TRACER_SNAPSHOT */
-
 static int __tracing_resize_ring_buffer(struct trace_array *tr,
 					unsigned long size, int cpu)
 {
@@ -5683,9 +5054,8 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
 	return ret;
 }
 
-static ssize_t
-tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
-		   size_t cnt, loff_t *ppos)
+ssize_t tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
+			   size_t cnt, loff_t *ppos)
 {
 	char buf[64];
 	int r;
@@ -5697,9 +5067,8 @@ tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 
-static ssize_t
-tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
-		    size_t cnt, loff_t *ppos)
+ssize_t tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
+			    size_t cnt, loff_t *ppos)
 {
 	unsigned long val;
 	int ret;
@@ -5741,28 +5110,6 @@ tracing_thresh_write(struct file *filp, const char __user *ubuf,
 	return cnt;
 }
 
-#ifdef CONFIG_TRACER_MAX_TRACE
-
-static ssize_t
-tracing_max_lat_read(struct file *filp, char __user *ubuf,
-		     size_t cnt, loff_t *ppos)
-{
-	struct trace_array *tr = filp->private_data;
-
-	return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos);
-}
-
-static ssize_t
-tracing_max_lat_write(struct file *filp, const char __user *ubuf,
-		      size_t cnt, loff_t *ppos)
-{
-	struct trace_array *tr = filp->private_data;
-
-	return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos);
-}
-
-#endif
-
 static int open_pipe_on_cpu(struct trace_array *tr, int cpu)
 {
 	if (cpu == RING_BUFFER_ALL_CPUS) {
@@ -7140,194 +6487,6 @@ u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_eve
 	return ring_buffer_event_time_stamp(buffer, rbe);
 }
 
-struct ftrace_buffer_info {
-	struct trace_iterator	iter;
-	void			*spare;
-	unsigned int		spare_cpu;
-	unsigned int		spare_size;
-	unsigned int		read;
-};
-
-#ifdef CONFIG_TRACER_SNAPSHOT
-static int tracing_snapshot_open(struct inode *inode, struct file *file)
-{
-	struct trace_array *tr = inode->i_private;
-	struct trace_iterator *iter;
-	struct seq_file *m;
-	int ret;
-
-	ret = tracing_check_open_get_tr(tr);
-	if (ret)
-		return ret;
-
-	if (file->f_mode & FMODE_READ) {
-		iter = __tracing_open(inode, file, true);
-		if (IS_ERR(iter))
-			ret = PTR_ERR(iter);
-	} else {
-		/* Writes still need the seq_file to hold the private data */
-		ret = -ENOMEM;
-		m = kzalloc_obj(*m);
-		if (!m)
-			goto out;
-		iter = kzalloc_obj(*iter);
-		if (!iter) {
-			kfree(m);
-			goto out;
-		}
-		ret = 0;
-
-		iter->tr = tr;
-		iter->array_buffer = &tr->snapshot_buffer;
-		iter->cpu_file = tracing_get_cpu(inode);
-		m->private = iter;
-		file->private_data = m;
-	}
-out:
-	if (ret < 0)
-		trace_array_put(tr);
-
-	return ret;
-}
-
-static void tracing_swap_cpu_buffer(void *tr)
-{
-	update_max_tr_single((struct trace_array *)tr, current, smp_processor_id());
-}
-
-static ssize_t
-tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
-		       loff_t *ppos)
-{
-	struct seq_file *m = filp->private_data;
-	struct trace_iterator *iter = m->private;
-	struct trace_array *tr = iter->tr;
-	unsigned long val;
-	int ret;
-
-	ret = tracing_update_buffers(tr);
-	if (ret < 0)
-		return ret;
-
-	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
-	if (ret)
-		return ret;
-
-	guard(mutex)(&trace_types_lock);
-
-	if (tracer_uses_snapshot(tr->current_trace))
-		return -EBUSY;
-
-	local_irq_disable();
-	arch_spin_lock(&tr->max_lock);
-	if (tr->cond_snapshot)
-		ret = -EBUSY;
-	arch_spin_unlock(&tr->max_lock);
-	local_irq_enable();
-	if (ret)
-		return ret;
-
-	switch (val) {
-	case 0:
-		if (iter->cpu_file != RING_BUFFER_ALL_CPUS)
-			return -EINVAL;
-		if (tr->allocated_snapshot)
-			free_snapshot(tr);
-		break;
-	case 1:
-/* Only allow per-cpu swap if the ring buffer supports it */
-#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
-		if (iter->cpu_file != RING_BUFFER_ALL_CPUS)
-			return -EINVAL;
-#endif
-		if (tr->allocated_snapshot)
-			ret = resize_buffer_duplicate_size(&tr->snapshot_buffer,
-					&tr->array_buffer, iter->cpu_file);
-
-		ret = tracing_arm_snapshot_locked(tr);
-		if (ret)
-			return ret;
-
-		/* Now, we're going to swap */
-		if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
-			local_irq_disable();
-			update_max_tr(tr, current, smp_processor_id(), NULL);
-			local_irq_enable();
-		} else {
-			smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer,
-						 (void *)tr, 1);
-		}
-		tracing_disarm_snapshot(tr);
-		break;
-	default:
-		if (tr->allocated_snapshot) {
-			if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
-				tracing_reset_online_cpus(&tr->snapshot_buffer);
-			else
-				tracing_reset_cpu(&tr->snapshot_buffer, iter->cpu_file);
-		}
-		break;
-	}
-
-	if (ret >= 0) {
-		*ppos += cnt;
-		ret = cnt;
-	}
-
-	return ret;
-}
-
-static int tracing_snapshot_release(struct inode *inode, struct file *file)
-{
-	struct seq_file *m = file->private_data;
-	int ret;
-
-	ret = tracing_release(inode, file);
-
-	if (file->f_mode & FMODE_READ)
-		return ret;
-
-	/* If write only, the seq_file is just a stub */
-	if (m)
-		kfree(m->private);
-	kfree(m);
-
-	return 0;
-}
-
-static int tracing_buffers_open(struct inode *inode, struct file *filp);
-static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
-				    size_t count, loff_t *ppos);
-static int tracing_buffers_release(struct inode *inode, struct file *file);
-static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
-		   struct pipe_inode_info *pipe, size_t len, unsigned int flags);
-
-static int snapshot_raw_open(struct inode *inode, struct file *filp)
-{
-	struct ftrace_buffer_info *info;
-	int ret;
-
-	/* The following checks for tracefs lockdown */
-	ret = tracing_buffers_open(inode, filp);
-	if (ret < 0)
-		return ret;
-
-	info = filp->private_data;
-
-	if (tracer_uses_snapshot(info->iter.trace)) {
-		tracing_buffers_release(inode, filp);
-		return -EBUSY;
-	}
-
-	info->iter.snapshot = true;
-	info->iter.array_buffer = &info->iter.tr->snapshot_buffer;
-
-	return ret;
-}
-
-#endif /* CONFIG_TRACER_SNAPSHOT */
-
-
 static const struct file_operations tracing_thresh_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_thresh_read,
@@ -7335,16 +6494,6 @@ static const struct file_operations tracing_thresh_fops = {
 	.llseek		= generic_file_llseek,
 };
 
-#ifdef CONFIG_TRACER_MAX_TRACE
-static const struct file_operations tracing_max_lat_fops = {
-	.open		= tracing_open_generic_tr,
-	.read		= tracing_max_lat_read,
-	.write		= tracing_max_lat_write,
-	.llseek		= generic_file_llseek,
-	.release	= tracing_release_generic_tr,
-};
-#endif
-
 static const struct file_operations set_tracer_fops = {
 	.open		= tracing_open_generic_tr,
 	.read		= tracing_set_trace_read,
@@ -7431,24 +6580,6 @@ static const struct file_operations last_boot_fops = {
 	.release	= tracing_seq_release,
 };
 
-#ifdef CONFIG_TRACER_SNAPSHOT
-static const struct file_operations snapshot_fops = {
-	.open		= tracing_snapshot_open,
-	.read		= seq_read,
-	.write		= tracing_snapshot_write,
-	.llseek		= tracing_lseek,
-	.release	= tracing_snapshot_release,
-};
-
-static const struct file_operations snapshot_raw_fops = {
-	.open		= snapshot_raw_open,
-	.read		= tracing_buffers_read,
-	.release	= tracing_buffers_release,
-	.splice_read	= tracing_buffers_splice_read,
-};
-
-#endif /* CONFIG_TRACER_SNAPSHOT */
-
 /*
  * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
  * @filp: The active open file structure
@@ -7808,7 +6939,7 @@ static const struct file_operations tracing_err_log_fops = {
 	.release        = tracing_err_log_release,
 };
 
-static int tracing_buffers_open(struct inode *inode, struct file *filp)
+int tracing_buffers_open(struct inode *inode, struct file *filp)
 {
 	struct trace_array *tr = inode->i_private;
 	struct ftrace_buffer_info *info;
@@ -7856,9 +6987,8 @@ tracing_buffers_poll(struct file *filp, poll_table *poll_t