tracing: Remove markers

Now that the last users of markers have migrated to the event
tracer we can kill off the (now orphan) support code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090917173527.GA1699@lst.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 0 insertions, 930 deletions

diff --git a/kernel/marker.c b/kernel/marker.c
deleted file mode 100644
index ea54f26..0000000
--- a/kernel/marker.c
+++ /dev/null
@@ -1,930 +0,0 @@
-/*
- * Copyright (C) 2007 Mathieu Desnoyers
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- */
-#include <linux/module.h>
-#include <linux/mutex.h>
-#include <linux/types.h>
-#include <linux/jhash.h>
-#include <linux/list.h>
-#include <linux/rcupdate.h>
-#include <linux/marker.h>
-#include <linux/err.h>
-#include <linux/slab.h>
-
-extern struct marker __start___markers[];
-extern struct marker __stop___markers[];
-
-/* Set to 1 to enable marker debug output */
-static const int marker_debug;
-
-/*
- * markers_mutex nests inside module_mutex. Markers mutex protects the builtin
- * and module markers and the hash table.
- */
-static DEFINE_MUTEX(markers_mutex);
-
-/*
- * Marker hash table, containing the active markers.
- * Protected by module_mutex.
- */
-#define MARKER_HASH_BITS 6
-#define MARKER_TABLE_SIZE (1 << MARKER_HASH_BITS)
-static struct hlist_head marker_table[MARKER_TABLE_SIZE];
-
-/*
- * Note about RCU :
- * It is used to make sure every handler has finished using its private data
- * between two consecutive operation (add or remove) on a given marker.  It is
- * also used to delay the free of multiple probes array until a quiescent state
- * is reached.
- * marker entries modifications are protected by the markers_mutex.
- */
-struct marker_entry {
-	struct hlist_node hlist;
-	char *format;
-			/* Probe wrapper */
-	void (*call)(const struct marker *mdata, void *call_private, ...);
-	struct marker_probe_closure single;
-	struct marker_probe_closure *multi;
-	int refcount;	/* Number of times armed. 0 if disarmed. */
-	struct rcu_head rcu;
-	void *oldptr;
-	int rcu_pending;
-	unsigned char ptype:1;
-	unsigned char format_allocated:1;
-	char name[0];	/* Contains name'\0'format'\0' */
-};
-
-/**
- * __mark_empty_function - Empty probe callback
- * @probe_private: probe private data
- * @call_private: call site private data
- * @fmt: format string
- * @...: variable argument list
- *
- * Empty callback provided as a probe to the markers. By providing this to a
- * disabled marker, we make sure the  execution flow is always valid even
- * though the function pointer change and the marker enabling are two distinct
- * operations that modifies the execution flow of preemptible code.
- */
-notrace void __mark_empty_function(void *probe_private, void *call_private,
-	const char *fmt, va_list *args)
-{
-}
-EXPORT_SYMBOL_GPL(__mark_empty_function);
-
-/*
- * marker_probe_cb Callback that prepares the variable argument list for probes.
- * @mdata: pointer of type struct marker
- * @call_private: caller site private data
- * @...:  Variable argument list.
- *
- * Since we do not use "typical" pointer based RCU in the 1 argument case, we
- * need to put a full smp_rmb() in this branch. This is why we do not use
- * rcu_dereference() for the pointer read.
- */
-notrace void marker_probe_cb(const struct marker *mdata,
-		void *call_private, ...)
-{
-	va_list args;
-	char ptype;
-
-	/*
-	 * rcu_read_lock_sched does two things : disabling preemption to make
-	 * sure the teardown of the callbacks can be done correctly when they
-	 * are in modules and they insure RCU read coherency.
-	 */
-	rcu_read_lock_sched_notrace();
-	ptype = mdata->ptype;
-	if (likely(!ptype)) {
-		marker_probe_func *func;
-		/* Must read the ptype before ptr. They are not data dependant,
-		 * so we put an explicit smp_rmb() here. */
-		smp_rmb();
-		func = mdata->single.func;
-		/* Must read the ptr before private data. They are not data
-		 * dependant, so we put an explicit smp_rmb() here. */
-		smp_rmb();
-		va_start(args, call_private);
-		func(mdata->single.probe_private, call_private, mdata->format,
-			&args);
-		va_end(args);
-	} else {
-		struct marker_probe_closure *multi;
-		int i;
-		/*
-		 * Read mdata->ptype before mdata->multi.
-		 */
-		smp_rmb();
-		multi = mdata->multi;
-		/*
-		 * multi points to an array, therefore accessing the array
-		 * depends on reading multi. However, even in this case,
-		 * we must insure that the pointer is read _before_ the array
-		 * data. Same as rcu_dereference, but we need a full smp_rmb()
-		 * in the fast path, so put the explicit barrier here.
-		 */
-		smp_read_barrier_depends();
-		for (i = 0; multi[i].func; i++) {
-			va_start(args, call_private);
-			multi[i].func(multi[i].probe_private, call_private,
-				mdata->format, &args);
-			va_end(args);
-		}
-	}
-	rcu_read_unlock_sched_notrace();
-}
-EXPORT_SYMBOL_GPL(marker_probe_cb);
-
-/*
- * marker_probe_cb Callback that does not prepare the variable argument list.
- * @mdata: pointer of type struct marker
- * @call_private: caller site private data
- * @...:  Variable argument list.
- *
- * Should be connected to markers "MARK_NOARGS".
- */
-static notrace void marker_probe_cb_noarg(const struct marker *mdata,
-		void *call_private, ...)
-{
-	va_list args;	/* not initialized */
-	char ptype;
-
-	rcu_read_lock_sched_notrace();
-	ptype = mdata->ptype;
-	if (likely(!ptype)) {
-		marker_probe_func *func;
-		/* Must read the ptype before ptr. They are not data dependant,
-		 * so we put an explicit smp_rmb() here. */
-		smp_rmb();
-		func = mdata->single.func;
-		/* Must read the ptr before private data. They are not data
-		 * dependant, so we put an explicit smp_rmb() here. */
-		smp_rmb();
-		func(mdata->single.probe_private, call_private, mdata->format,
-			&args);
-	} else {
-		struct marker_probe_closure *multi;
-		int i;
-		/*
-		 * Read mdata->ptype before mdata->multi.
-		 */
-		smp_rmb();
-		multi = mdata->multi;
-		/*
-		 * multi points to an array, therefore accessing the array
-		 * depends on reading multi. However, even in this case,
-		 * we must insure that the pointer is read _before_ the array
-		 * data. Same as rcu_dereference, but we need a full smp_rmb()
-		 * in the fast path, so put the explicit barrier here.
-		 */
-		smp_read_barrier_depends();
-		for (i = 0; multi[i].func; i++)
-			multi[i].func(multi[i].probe_private, call_private,
-				mdata->format, &args);
-	}
-	rcu_read_unlock_sched_notrace();
-}
-
-static void free_old_closure(struct rcu_head *head)
-{
-	struct marker_entry *entry = container_of(head,
-		struct marker_entry, rcu);
-	kfree(entry->oldptr);
-	/* Make sure we free the data before setting the pending flag to 0 */
-	smp_wmb();
-	entry->rcu_pending = 0;
-}
-
-static void debug_print_probes(struct marker_entry *entry)
-{
-	int i;
-
-	if (!marker_debug)
-		return;
-
-	if (!entry->ptype) {
-		printk(KERN_DEBUG "Single probe : %p %p\n",
-			entry->single.func,
-			entry->single.probe_private);
-	} else {
-		for (i = 0; entry->multi[i].func; i++)
-			printk(KERN_DEBUG "Multi probe %d : %p %p\n", i,
-				entry->multi[i].func,
-				entry->multi[i].probe_private);
-	}
-}
-
-static struct marker_probe_closure *
-marker_entry_add_probe(struct marker_entry *entry,
-		marker_probe_func *probe, void *probe_private)
-{
-	int nr_probes = 0;
-	struct marker_probe_closure *old, *new;
-
-	WARN_ON(!probe);
-
-	debug_print_probes(entry);
-	old = entry->multi;
-	if (!entry->ptype) {
-		if (entry->single.func == probe &&
-				entry->single.probe_private == probe_private)
-			return ERR_PTR(-EBUSY);
-		if (entry->single.func == __mark_empty_function) {
-			/* 0 -> 1 probes */
-			entry->single.func = probe;
-			entry->single.probe_private = probe_private;
-			entry->refcount = 1;
-			entry->ptype = 0;
-			debug_print_probes(entry);
-			return NULL;
-		} else {
-			/* 1 -> 2 probes */
-			nr_probes = 1;
-			old = NULL;
-		}
-	} else {
-		/* (N -> N+1), (N != 0, 1) probes */
-		for (nr_probes = 0; old[nr_probes].func; nr_probes++)
-			if (old[nr_probes].func == probe
-					&& old[nr_probes].probe_private
-						== probe_private)
-				return ERR_PTR(-EBUSY);
-	}
-	/* + 2 : one for new probe, one for NULL func */
-	new = kzalloc((nr_probes + 2) * sizeof(struct marker_probe_closure),
-			GFP_KERNEL);
-	if (new == NULL)
-		return ERR_PTR(-ENOMEM);
-	if (!old)
-		new[0] = entry->single;
-	else
-		memcpy(new, old,
-			nr_probes * sizeof(struct marker_probe_closure));
-	new[nr_probes].func = probe;
-	new[nr_probes].probe_private = probe_private;
-	entry->refcount = nr_probes + 1;
-	entry->multi = new;
-	entry->ptype = 1;
-	debug_print_probes(entry);
-	return old;
-}
-
-static struct marker_probe_closure *
-marker_entry_remove_probe(struct marker_entry *entry,
-		marker_probe_func *probe, void *probe_private)
-{
-	int nr_probes = 0, nr_del = 0, i;
-	struct marker_probe_closure *old, *new;
-
-	old = entry->multi;
-
-	debug_print_probes(entry);
-	if (!entry->ptype) {
-		/* 0 -> N is an error */
-		WARN_ON(entry->single.func == __mark_empty_function);
-		/* 1 -> 0 probes */
-		WARN_ON(probe && entry->single.func != probe);
-		WARN_ON(entry->single.probe_private != probe_private);
-		entry->single.func = __mark_empty_function;
-		entry->refcount = 0;
-		entry->ptype = 0;
-		debug_print_probes(entry);
-		return NULL;
-	} else {
-		/* (N -> M), (N > 1, M >= 0) probes */
-		for (nr_probes = 0; old[nr_probes].func; nr_probes++) {
-			if ((!probe || old[nr_probes].func == probe)
-					&& old[nr_probes].probe_private
-						== probe_private)
-				nr_del++;
-		}
-	}
-
-	if (nr_probes - nr_del == 0) {
-		/* N -> 0, (N > 1) */
-		entry->single.func = __mark_empty_function;
-		entry->refcount = 0;
-		entry->ptype = 0;
-	} else if (nr_probes - nr_del == 1) {
-		/* N -> 1, (N > 1) */
-		for (i = 0; old[i].func; i++)
-			if ((probe && old[i].func != probe) ||
-					old[i].probe_private != probe_private)
-				entry->single = old[i];
-		entry->refcount = 1;
-		entry->ptype = 0;
-	} else {
-		int j = 0;
-		/* N -> M, (N > 1, M > 1) */
-		/* + 1 for NULL */
-		new = kzalloc((nr_probes - nr_del + 1)
-			* sizeof(struct marker_probe_closure), GFP_KERNEL);
-		if (new == NULL)
-			return ERR_PTR(-ENOMEM);
-		for (i = 0; old[i].func; i++)
-			if ((probe && old[i].func != probe) ||
-					old[i].probe_private != probe_private)
-				new[j++] = old[i];
-		entry->refcount = nr_probes - nr_del;
-		entry->ptype = 1;
-		entry->multi = new;
-	}
-	debug_print_probes(entry);
-	return old;
-}
-
-/*
- * Get marker if the marker is present in the marker hash table.
- * Must be called with markers_mutex held.
- * Returns NULL if not present.
- */
-static struct marker_entry *get_marker(const char *name)
-{
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct marker_entry *e;
-	u32 hash = jhash(name, strlen(name), 0);
-
-	head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
-	hlist_for_each_entry(e, node, head, hlist) {
-		if (!strcmp(name, e->name))
-			return e;
-	}
-	return NULL;
-}
-
-/*
- * Add the marker to the marker hash table. Must be called with markers_mutex
- * held.
- */
-static struct marker_entry *add_marker(const char *name, const char *format)
-{
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct marker_entry *e;
-	size_t name_len = strlen(name) + 1;
-	size_t format_len = 0;
-	u32 hash = jhash(name, name_len-1, 0);
-
-	if (format)
-		format_len = strlen(format) + 1;
-	head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
-	hlist_for_each_entry(e, node, head, hlist) {
-		if (!strcmp(name, e->name)) {
-			printk(KERN_NOTICE
-				"Marker %s busy\n", name);
-			return ERR_PTR(-EBUSY);	/* Already there */
-		}
-	}
-	/*
-	 * Using kmalloc here to allocate a variable length element. Could
-	 * cause some memory fragmentation if overused.
-	 */
-	e = kmalloc(sizeof(struct marker_entry) + name_len + format_len,
-			GFP_KERNEL);
-	if (!e)
-		return ERR_PTR(-ENOMEM);
-	memcpy(&e->name[0], name, name_len);
-	if (format) {
-		e->format = &e->name[name_len];
-		memcpy(e->format, format, format_len);
-		if (strcmp(e->format, MARK_NOARGS) == 0)
-			e->call = marker_probe_cb_noarg;
-		else
-			e->call = marker_probe_cb;
-		trace_mark(core_marker_format, "name %s format %s",
-				e->name, e->format);
-	} else {
-		e->format = NULL;
-		e->call = marker_probe_cb;
-	}
-	e->single.func = __mark_empty_function;
-	e->single.probe_private = NULL;
-	e->multi = NULL;
-	e->ptype = 0;
-	e->format_allocated = 0;
-	e->refcount = 0;
-	e->rcu_pending = 0;
-	hlist_add_head(&e->hlist, head);
-	return e;
-}
-
-/*
- * Remove the marker from the marker hash table. Must be called with mutex_lock
- * held.
- */
-static int remove_marker(const char *name)
-{
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct marker_entry *e;
-	int found = 0;
-	size_t len = strlen(name) + 1;
-	u32 hash = jhash(name, len-1, 0);
-
-	head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
-	hlist_for_each_entry(e, node, head, hlist) {
-		if (!strcmp(name, e->name)) {
-			found = 1;
-			break;
-		}
-	}
-	if (!found)
-		return -ENOENT;
-	if (e->single.func != __mark_empty_function)
-		return -EBUSY;
-	hlist_del(&e->hlist);
-	if (e->format_allocated)
-		kfree(e->format);
-	/* Make sure the call_rcu has been executed */
-	if (e->rcu_pending)
-		rcu_barrier_sched();
-	kfree(e);
-	return 0;
-}
-
-/*
- * Set the mark_entry format to the format found in the element.
- */
-static int marker_set_format(struct marker_entry *entry, const char *format)
-{
-	entry->format = kstrdup(format, GFP_KERNEL);
-	if (!entry->format)
-		return -ENOMEM;
-	entry->format_allocated = 1;
-
-	trace_mark(core_marker_format, "name %s format %s",
-			entry->name, entry->format);
-	return 0;
-}
-
-/*
- * Sets the probe callback corresponding to one marker.
- */
-static int set_marker(struct marker_entry *entry, struct marker *elem,
-		int active)
-{
-	int ret = 0;
-	WARN_ON(strcmp(entry->name, elem->name) != 0);
-
-	if (entry->format) {
-		if (strcmp(entry->format, elem->format) != 0) {
-			printk(KERN_NOTICE
-				"Format mismatch for probe %s "
-				"(%s), marker (%s)\n",
-				entry->name,
-				entry->format,
-				elem->format);
-			return -EPERM;
-		}
-	} else {
-		ret = marker_set_format(entry, elem->format);
-		if (ret)
-			return ret;
-	}
-
-	/*
-	 * probe_cb setup (statically known) is done here. It is
-	 * asynchronous with the rest of execution, therefore we only
-	 * pass from a "safe" callback (with argument) to an "unsafe"
-	 * callback (does not set arguments).
-	 */
-	elem->call = entry->call;
-	/*
-	 * Sanity check :
-	 * We only update the single probe private data when the ptr is
-	 * set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1)
-	 */
-	WARN_ON(elem->single.func != __mark_empty_function
-		&& elem->single.probe_private != entry->single.probe_private
-		&& !elem->ptype);
-	elem->single.probe_private = entry->single.probe_private;
-	/*
-	 * Make sure the private data is valid when we update the
-	 * single probe ptr.
-	 */
-	smp_wmb();
-	elem->single.func = entry->single.func;
-	/*
-	 * We also make sure that the new probe callbacks array is consistent
-	 * before setting a pointer to it.
-	 */
-	rcu_assign_pointer(elem->multi, entry->multi);
-	/*
-	 * Update the function or multi probe array pointer before setting the
-	 * ptype.
-	 */
-	smp_wmb();
-	elem->ptype = entry->ptype;
-
-	if (elem->tp_name && (active ^ elem->state)) {
-		WARN_ON(!elem->tp_cb);
-		/*
-		 * It is ok to directly call the probe registration because type
-		 * checking has been done in the __trace_mark_tp() macro.
-		 */
-
-		if (active) {
-			/*
-			 * try_module_get should always succeed because we hold
-			 * lock_module() to get the tp_cb address.
-			 */
-			ret = try_module_get(__module_text_address(
-				(unsigned long)elem->tp_cb));
-			BUG_ON(!ret);
-			ret = tracepoint_probe_register_noupdate(
-				elem->tp_name,
-				elem->tp_cb);
-		} else {
-			ret = tracepoint_probe_unregister_noupdate(
-				elem->tp_name,
-				elem->tp_cb);
-			/*
-			 * tracepoint_probe_update_all() must be called
-			 * before the module containing tp_cb is unloaded.
-			 */
-			module_put(__module_text_address(
-				(unsigned long)elem->tp_cb));
-		}
-	}
-	elem->state = active;
-
-	return ret;
-}
-
-/*
- * Disable a marker and its probe callback.
- * Note: only waiting an RCU period after setting elem->call to the empty
- * function insures that the original callback is not used anymore. This insured
- * by rcu_read_lock_sched around the call site.
- */
-static void disable_marker(struct marker *elem)
-{
-	int ret;
-
-	/* leave "call" as is. It is known statically. */
-	if (elem->tp_name && elem->state) {
-		WARN_ON(!elem->tp_cb);
-		/*
-		 * It is ok to directly call the probe registration because type
-		 * checking has been done in the __trace_mark_tp() macro.
-		 */
-		ret = tracepoint_probe_unregister_noupdate(elem->tp_name,
-			elem->tp_cb);
-		WARN_ON(ret);
-		/*
-		 * tracepoint_probe_update_all() must be called
-		 * before the module containing tp_cb is unloaded.
-		 */
-		module_put(__module_text_address((unsigned long)elem->tp_cb));
-	}
-	elem->state = 0;
-	elem->single.func = __mark_empty_function;
-	/* Update the function before setting the ptype */
-	smp_wmb();
-	elem->ptype = 0;	/* single probe */
-	/*
-	 * Leave the private data and id there, because removal is racy and
-	 * should be done only after an RCU period. These are never used until
-	 * the next initialization anyway.
-	 */
-}
-
-/**
- * marker_update_probe_range - Update a probe range
- * @begin: beginning of the range
- * @end: end of the range
- *
- * Updates the probe callback corresponding to a range of markers.
- */
-void marker_update_probe_range(struct marker *begin,
-	struct marker *end)
-{
-	struct marker *iter;
-	struct marker_entry *mark_entry;
-
-	mutex_lock(&markers_mutex);
-	for (iter = begin; iter < end; iter++) {
-		mark_entry = get_marker(iter->name);
-		if (mark_entry) {
-			set_marker(mark_entry, iter, !!mark_entry->refcount);
-			/*
-			 * ignore error, continue
-			 */
-		} else {
-			disable_marker(iter);
-		}
-	}
-	mutex_unlock(&markers_mutex);
-}
-
-/*
- * Update probes, removing the faulty probes.
- *
- * Internal callback only changed before the first probe is connected to it.
- * Single probe private data can only be changed on 0 -> 1 and 2 -> 1
- * transitions.  All other transitions will leave the old private data valid.
- * This makes the non-atomicity of the callback/private data updates valid.
- *
- * "special case" updates :
- * 0 -> 1 callback
- * 1 -> 0 callback
- * 1 -> 2 callbacks
- * 2 -> 1 callbacks
- * Other updates all behave the same, just like the 2 -> 3 or 3 -> 2 updates.
- * Site effect : marker_set_format may delete the marker entry (creating a
- * replacement).
- */
-static void marker_update_probes(void)
-{
-	/* Core kernel markers */
-	marker_update_probe_range(__start___markers, __stop___markers);
-	/* Markers in modules. */
-	module_update_markers();
-	tracepoint_probe_update_all();
-}
-
-/**
- * marker_probe_register -  Connect a probe to a marker
- * @name: marker name
- * @format: format string
- * @probe: probe handler
- * @probe_private: probe private data
- *
- * private data must be a valid allocated memory address, or NULL.
- * Returns 0 if ok, error value on error.
- * The probe address must at least be aligned on the architecture pointer size.
- */
-int marker_probe_register(const char *name, const char *format,
-			marker_probe_func *probe, void *probe_private)
-{
-	struct marker_entry *entry;
-	int ret = 0;
-	struct marker_probe_closure *old;
-
-	mutex_lock(&markers_mutex);
-	entry = get_marker(name);
-	if (!entry) {
-		entry = add_marker(name, format);
-		if (IS_ERR(entry))
-			ret = PTR_ERR(entry);
-	} else if (format) {
-		if (!entry->format)
-			ret = marker_set_format(entry, format);
-		else if (strcmp(entry->format, format))
-			ret = -EPERM;
-	}
-	if (ret)
-		goto end;
-
-	/*
-	 * If we detect that a call_rcu is pending for this marker,
-	 * make sure it's executed now.
-	 */
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	old = marker_entry_add_probe(entry, probe, probe_private);
-	if (IS_ERR(old)) {
-		ret = PTR_ERR(old);
-		goto end;
-	}
-	mutex_unlock(&markers_mutex);
-	marker_update_probes();
-	mutex_lock(&markers_mutex);
-	entry = get_marker(name);
-	if (!entry)
-		goto end;
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	entry->oldptr = old;
-	entry->rcu_pending = 1;
-	/* write rcu_pending before calling the RCU callback */
-	smp_wmb();
-	call_rcu_sched(&entry->rcu, free_old_closure);
-end:
-	mutex_unlock(&markers_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(marker_probe_register);
-
-/**
- * marker_probe_unregister -  Disconnect a probe from a marker
- * @name: marker name
- * @probe: probe function pointer
- * @probe_private: probe private data
- *
- * Returns the private data given to marker_probe_register, or an ERR_PTR().
- * We do not need to call a synchronize_sched to make sure the probes have
- * finished running before doing a module unload, because the module unload
- * itself uses stop_machine(), which insures that every preempt disabled section
- * have finished.
- */
-int marker_probe_unregister(const char *name,
-	marker_probe_func *probe, void *probe_private)
-{
-	struct marker_entry *entry;
-	struct marker_probe_closure *old;
-	int ret = -ENOENT;
-
-	mutex_lock(&markers_mutex);
-	entry = get_marker(name);
-	if (!entry)
-		goto end;
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	old = marker_entry_remove_probe(entry, probe, probe_private);
-	mutex_unlock(&markers_mutex);
-	marker_update_probes();
-	mutex_lock(&markers_mutex);
-	entry = get_marker(name);
-	if (!entry)
-		goto end;
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	entry->oldptr = old;
-	entry->rcu_pending = 1;
-	/* write rcu_pending before calling the RCU callback */
-	smp_wmb();
-	call_rcu_sched(&entry->rcu, free_old_closure);
-	remove_marker(name);	/* Ignore busy error message */
-	ret = 0;
-end:
-	mutex_unlock(&markers_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(marker_probe_unregister);
-
-static struct marker_entry *
-get_marker_from_private_data(marker_probe_func *probe, void *probe_private)
-{
-	struct marker_entry *entry;
-	unsigned int i;
-	struct hlist_head *head;
-	struct hlist_node *node;
-
-	for (i = 0; i < MARKER_TABLE_SIZE; i++) {
-		head = &marker_table[i];
-		hlist_for_each_entry(entry, node, head, hlist) {
-			if (!entry->ptype) {
-				if (entry->single.func == probe
-						&& entry->single.probe_private
-						== probe_private)
-					return entry;
-			} else {
-				struct marker_probe_closure *closure;
-				closure = entry->multi;
-				for (i = 0; closure[i].func; i++) {
-					if (closure[i].func == probe &&
-							closure[i].probe_private
-							== probe_private)
-						return entry;
-				}
-			}
-		}
-	}
-	return NULL;
-}
-
-/**
- * marker_probe_unregister_private_data -  Disconnect a probe from a marker
- * @probe: probe function
- * @probe_private: probe private data
- *
- * Unregister a probe by providing the registered private data.
- * Only removes the first marker found in hash table.
- * Return 0 on success or error value.
- * We do not need to call a synchronize_sched to make sure the probes have
- * finished running before doing a module unload, because the module unload
- * itself uses stop_machine(), which insures that every preempt disabled section
- * have finished.
- */
-int marker_probe_unregister_private_data(marker_probe_func *probe,
-		void *probe_private)
-{
-	struct marker_entry *entry;
-	int ret = 0;
-	struct marker_probe_closure *old;
-
-	mutex_lock(&markers_mutex);
-	entry = get_marker_from_private_data(probe, probe_private);
-	if (!entry) {
-		ret = -ENOENT;
-		goto end;
-	}
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	old = marker_entry_remove_probe(entry, NULL, probe_private);
-	mutex_unlock(&markers_mutex);
-	marker_update_probes();
-	mutex_lock(&markers_mutex);
-	entry = get_marker_from_private_data(probe, probe_private);
-	if (!entry)
-		goto end;
-	if (entry->rcu_pending)
-		rcu_barrier_sched();
-	entry->oldptr = old;
-	entry->rcu_pending = 1;
-	/* write rcu_pending before calling the RCU callback */
-	smp_wmb();
-	call_rcu_sched(&entry->rcu, free_old_closure);
-	remove_marker(entry->name);	/* Ignore busy error message */
-end:
-	mutex_unlock(&markers_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(marker_probe_unregister_private_data);
-
-/**
- * marker_get_private_data - Get a marker's probe private data
- * @name: marker name
- * @probe: probe to match
- * @num: get the nth matching probe's private data
- *
- * Returns the nth private data pointer (starting from 0) matching, or an
- * ERR_PTR.
- * Returns the private data pointer, or an ERR_PTR.
- * The private data pointer should _only_ be dereferenced if the caller is the
- * owner of the data, or its content could vanish. This is mostly used to
- * confirm that a caller is the owner of a registered probe.
- */
-void *marker_get_private_data(const char *name, marker_probe_func *probe,
-		int num)
-{
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct marker_entry *e;
-	size_t name_len = strlen(name) + 1;
-	u32 hash = jhash(name, name_len-1, 0);
-	int i;
-
-	head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)];
-	hlist_for_each_entry(e, node, head, hlist) {
-		if (!strcmp(name, e->name)) {
-			if (!e->ptype) {
-				if (num == 0 && e->single.func == probe)
-					return e->single.probe_private;
-			} else {
-				struct marker_probe_closure *closure;
-				int match = 0;
-				closure = e->multi;
-				for (i = 0; closure[i].func; i++) {
-					if (closure[i].func != probe)
-						continue;
-					if (match++ == num)
-						return closure[i].probe_private;
-				}
-			}
-			break;
-		}
-	}
-	return ERR_PTR(-ENOENT);
-}
-EXPORT_SYMBOL_GPL(marker_get_private_data);
-
-#ifdef CONFIG_MODULES
-
-int marker_module_notify(struct notifier_block *self,
-			 unsigned long val, void *data)
-{
-	struct module *mod = data;
-
-	switch (val) {
-	case MODULE_STATE_COMING:
-		marker_update_probe_range(mod->markers,
-			mod->markers + mod->num_markers);
-		break;
-	case MODULE_STATE_GOING:
-		marker_update_probe_range(mod->markers,
-			mod->markers + mod->num_markers);
-		break;
-	}
-	return 0;
-}
-
-struct notifier_block marker_module_nb = {
-	.notifier_call = marker_module_notify,
-	.priority = 0,
-};
-
-static int init_markers(void)
-{
-	return register_module_notifier(&marker_module_nb);
-}
-__initcall(init_markers);
-
-#endif /* CONFIG_MODULES */