dynamic debug: combine dprintk and dynamic printk

This patch combines Greg Bank's dprintk() work with the existing dynamic
printk patchset, we are now calling it 'dynamic debug'.

The new feature of this patchset is a richer /debugfs control file interface,
(an example output from my system is at the bottom), which allows fined grained
control over the the debug output. The output can be controlled by function,
file, module, format string, and line number.

for example, enabled all debug messages in module 'nf_conntrack':

echo -n 'module nf_conntrack +p' > /mnt/debugfs/dynamic_debug/control

to disable them:

echo -n 'module nf_conntrack -p' > /mnt/debugfs/dynamic_debug/control

A further explanation can be found in the documentation patch.

Signed-off-by: Greg Banks <gnb@sgi.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 0 insertions, 414 deletions

diff --git a/lib/dynamic_printk.c b/lib/dynamic_printk.c
deleted file mode 100644
index 165a19763dc9..000000000000
--- a/lib/dynamic_printk.c
+++ /dev/null
@@ -1,414 +0,0 @@
-/*
- * lib/dynamic_printk.c
- *
- * make pr_debug()/dev_dbg() calls runtime configurable based upon their
- * their source module.
- *
- * Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com>
- */
-
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/uaccess.h>
-#include <linux/seq_file.h>
-#include <linux/debugfs.h>
-#include <linux/fs.h>
-
-extern struct mod_debug __start___verbose[];
-extern struct mod_debug __stop___verbose[];
-
-struct debug_name {
-	struct hlist_node hlist;
-	struct hlist_node hlist2;
-	int hash1;
-	int hash2;
-	char *name;
-	int enable;
-	int type;
-};
-
-static int nr_entries;
-static int num_enabled;
-int dynamic_enabled = DYNAMIC_ENABLED_NONE;
-static struct hlist_head module_table[DEBUG_HASH_TABLE_SIZE] =
-	{ [0 ... DEBUG_HASH_TABLE_SIZE-1] = HLIST_HEAD_INIT };
-static struct hlist_head module_table2[DEBUG_HASH_TABLE_SIZE] =
-	{ [0 ... DEBUG_HASH_TABLE_SIZE-1] = HLIST_HEAD_INIT };
-static DECLARE_MUTEX(debug_list_mutex);
-
-/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
- * bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
- * use independent hash functions, to reduce the chance of false positives.
- */
-long long dynamic_printk_enabled;
-EXPORT_SYMBOL_GPL(dynamic_printk_enabled);
-long long dynamic_printk_enabled2;
-EXPORT_SYMBOL_GPL(dynamic_printk_enabled2);
-
-/* returns the debug module pointer. */
-static struct debug_name *find_debug_module(char *module_name)
-{
-	int i;
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct debug_name *element;
-
-	element = NULL;
-	for (i = 0; i < DEBUG_HASH_TABLE_SIZE; i++) {
-		head = &module_table[i];
-		hlist_for_each_entry_rcu(element, node, head, hlist)
-			if (!strcmp(element->name, module_name))
-				return element;
-	}
-	return NULL;
-}
-
-/* returns the debug module pointer. */
-static struct debug_name *find_debug_module_hash(char *module_name, int hash)
-{
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct debug_name *element;
-
-	element = NULL;
-	head = &module_table[hash];
-	hlist_for_each_entry_rcu(element, node, head, hlist)
-		if (!strcmp(element->name, module_name))
-			return element;
-	return NULL;
-}
-
-/* caller must hold mutex*/
-static int __add_debug_module(char *mod_name, int hash, int hash2)
-{
-	struct debug_name *new;
-	char *module_name;
-	int ret = 0;
-
-	if (find_debug_module(mod_name)) {
-		ret = -EINVAL;
-		goto out;
-	}
-	module_name = kmalloc(strlen(mod_name) + 1, GFP_KERNEL);
-	if (!module_name) {
-		ret = -ENOMEM;
-		goto out;
-	}
-	module_name = strcpy(module_name, mod_name);
-	module_name[strlen(mod_name)] = '\0';
-	new = kzalloc(sizeof(struct debug_name), GFP_KERNEL);
-	if (!new) {
-		kfree(module_name);
-		ret = -ENOMEM;
-		goto out;
-	}
-	INIT_HLIST_NODE(&new->hlist);
-	INIT_HLIST_NODE(&new->hlist2);
-	new->name = module_name;
-	new->hash1 = hash;
-	new->hash2 = hash2;
-	hlist_add_head_rcu(&new->hlist, &module_table[hash]);
-	hlist_add_head_rcu(&new->hlist2, &module_table2[hash2]);
-	nr_entries++;
-out:
-	return ret;
-}
-
-int unregister_dynamic_debug_module(char *mod_name)
-{
-	struct debug_name *element;
-	int ret = 0;
-
-	down(&debug_list_mutex);
-	element = find_debug_module(mod_name);
-	if (!element) {
-		ret = -EINVAL;
-		goto out;
-	}
-	hlist_del_rcu(&element->hlist);
-	hlist_del_rcu(&element->hlist2);
-	synchronize_rcu();
-	kfree(element->name);
-	if (element->enable)
-		num_enabled--;
-	kfree(element);
-	nr_entries--;
-out:
-	up(&debug_list_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(unregister_dynamic_debug_module);
-
-int register_dynamic_debug_module(char *mod_name, int type, char *share_name,
-					char *flags, int hash, int hash2)
-{
-	struct debug_name *elem;
-	int ret = 0;
-
-	down(&debug_list_mutex);
-	elem = find_debug_module(mod_name);
-	if (!elem) {
-		if (__add_debug_module(mod_name, hash, hash2))
-			goto out;
-		elem = find_debug_module(mod_name);
-		if (dynamic_enabled == DYNAMIC_ENABLED_ALL &&
-				!strcmp(mod_name, share_name)) {
-			elem->enable = true;
-			num_enabled++;
-		}
-	}
-	elem->type |= type;
-out:
-	up(&debug_list_mutex);
-	return ret;
-}
-EXPORT_SYMBOL_GPL(register_dynamic_debug_module);
-
-int __dynamic_dbg_enabled_helper(char *mod_name, int type, int value, int hash)
-{
-	struct debug_name *elem;
-	int ret = 0;
-
-	if (dynamic_enabled == DYNAMIC_ENABLED_ALL)
-		return 1;
-	rcu_read_lock();
-	elem = find_debug_module_hash(mod_name, hash);
-	if (elem && elem->enable)
-		ret = 1;
-	rcu_read_unlock();
-	return ret;
-}
-EXPORT_SYMBOL_GPL(__dynamic_dbg_enabled_helper);
-
-static void set_all(bool enable)
-{
-	struct debug_name *e;
-	struct hlist_node *node;
-	int i;
-	long long enable_mask;
-
-	for (i = 0; i < DEBUG_HASH_TABLE_SIZE; i++) {
-		if (module_table[i].first != NULL) {
-			hlist_for_each_entry(e, node, &module_table[i], hlist) {
-				e->enable = enable;
-			}
-		}
-	}
-	if (enable)
-		enable_mask = ULLONG_MAX;
-	else
-		enable_mask = 0;
-	dynamic_printk_enabled = enable_mask;
-	dynamic_printk_enabled2 = enable_mask;
-}
-
-static int disabled_hash(int i, bool first_table)
-{
-	struct debug_name *e;
-	struct hlist_node *node;
-
-	if (first_table) {
-		hlist_for_each_entry(e, node, &module_table[i], hlist) {
-			if (e->enable)
-				return 0;
-		}
-	} else {
-		hlist_for_each_entry(e, node, &module_table2[i], hlist2) {
-			if (e->enable)
-				return 0;
-		}
-	}
-	return 1;
-}
-
-static ssize_t pr_debug_write(struct file *file, const char __user *buf,
-				size_t length, loff_t *ppos)
-{
-	char *buffer, *s, *value_str, *setting_str;
-	int err, value;
-	struct debug_name *elem = NULL;
-	int all = 0;
-
-	if (length > PAGE_SIZE || length < 0)
-		return -EINVAL;
-
-	buffer = (char *)__get_free_page(GFP_KERNEL);
-	if (!buffer)
-		return -ENOMEM;
-
-	err = -EFAULT;
-	if (copy_from_user(buffer, buf, length))
-		goto out;
-
-	err = -EINVAL;
-	if (length < PAGE_SIZE)
-		buffer[length] = '\0';
-	else if (buffer[PAGE_SIZE-1])
-		goto out;
-
-	err = -EINVAL;
-	down(&debug_list_mutex);
-
-	if (strncmp("set", buffer, 3))
-		goto out_up;
-	s = buffer + 3;
-	setting_str = strsep(&s, "=");
-	if (s == NULL)
-		goto out_up;
-	setting_str = strstrip(setting_str);
-	value_str = strsep(&s, " ");
-	if (s == NULL)
-		goto out_up;
-	s = strstrip(s);
-	if (!strncmp(s, "all", 3))
-		all = 1;
-	else
-		elem = find_debug_module(s);
-	if (!strncmp(setting_str, "enable", 6)) {
-		value = !!simple_strtol(value_str, NULL, 10);
-		if (all) {
-			if (value) {
-				set_all(true);
-				num_enabled = nr_entries;
-				dynamic_enabled = DYNAMIC_ENABLED_ALL;
-			} else {
-				set_all(false);
-				num_enabled = 0;
-				dynamic_enabled = DYNAMIC_ENABLED_NONE;
-			}
-			err = 0;
-		} else if (elem) {
-			if (value && (elem->enable == 0)) {
-				dynamic_printk_enabled |= (1LL << elem->hash1);
-				dynamic_printk_enabled2 |= (1LL << elem->hash2);
-				elem->enable = 1;
-				num_enabled++;
-				dynamic_enabled = DYNAMIC_ENABLED_SOME;
-				err = 0;
-				printk(KERN_DEBUG
-					"debugging enabled for module %s\n",
-					elem->name);
-			} else if (!value && (elem->enable == 1)) {
-				elem->enable = 0;
-				num_enabled--;
-				if (disabled_hash(elem->hash1, true))
-					dynamic_printk_enabled &=
-							~(1LL << elem->hash1);
-				if (disabled_hash(elem->hash2, false))
-					dynamic_printk_enabled2 &=
-							~(1LL << elem->hash2);
-				if (num_enabled)
-					dynamic_enabled = DYNAMIC_ENABLED_SOME;
-				else
-					dynamic_enabled = DYNAMIC_ENABLED_NONE;
-				err = 0;
-				printk(KERN_DEBUG
-					"debugging disabled for module %s\n",
-					elem->name);
-			}
-		}
-	}
-	if (!err)
-		err = length;
-out_up:
-	up(&debug_list_mutex);
-out:
-	free_page((unsigned long)buffer);
-	return err;
-}
-
-static void *pr_debug_seq_start(struct seq_file *f, loff_t *pos)
-{
-	return (*pos < DEBUG_HASH_TABLE_SIZE) ? pos : NULL;
-}
-
-static void *pr_debug_seq_next(struct seq_file *s, void *v, loff_t *pos)
-{
-	(*pos)++;
-	if (*pos >= DEBUG_HASH_TABLE_SIZE)
-		return NULL;
-	return pos;
-}
-
-static void pr_debug_seq_stop(struct seq_file *s, void *v)
-{
-	/* Nothing to do */
-}
-
-static int pr_debug_seq_show(struct seq_file *s, void *v)
-{
-	struct hlist_head *head;
-	struct hlist_node *node;
-	struct debug_name *elem;
-	unsigned int i = *(loff_t *) v;
-
-	rcu_read_lock();
-	head = &module_table[i];
-	hlist_for_each_entry_rcu(elem, node, head, hlist) {
-		seq_printf(s, "%s enabled=%d", elem->name, elem->enable);
-		seq_printf(s, "\n");
-	}
-	rcu_read_unlock();
-	return 0;
-}
-
-static struct seq_operations pr_debug_seq_ops = {
-	.start = pr_debug_seq_start,
-	.next  = pr_debug_seq_next,
-	.stop  = pr_debug_seq_stop,
-	.show  = pr_debug_seq_show
-};
-
-static int pr_debug_open(struct inode *inode, struct file *filp)
-{
-	return seq_open(filp, &pr_debug_seq_ops);
-}
-
-static const struct file_operations pr_debug_operations = {
-	.open		= pr_debug_open,
-	.read		= seq_read,
-	.write		= pr_debug_write,
-	.llseek		= seq_lseek,
-	.release	= seq_release,
-};
-
-static int __init dynamic_printk_init(void)
-{
-	struct dentry *dir, *file;
-	struct mod_debug *iter;
-	unsigned long value;
-
-	dir = debugfs_create_dir("dynamic_printk", NULL);
-	if (!dir)
-		return -ENOMEM;
-	file = debugfs_create_file("modules", 0644, dir, NULL,
-					&pr_debug_operations);
-	if (!file) {
-		debugfs_remove(dir);
-		return -ENOMEM;
-	}
-	for (value = (unsigned long)__start___verbose;
-		value < (unsigned long)__stop___verbose;
-		value += sizeof(struct mod_debug)) {
-			iter = (struct mod_debug *)value;
-			register_dynamic_debug_module(iter->modname,
-				iter->type,
-				iter->logical_modname,
-				iter->flag_names, iter->hash, iter->hash2);
-	}
-	if (dynamic_enabled == DYNAMIC_ENABLED_ALL)
-		set_all(true);
-	return 0;
-}
-module_init(dynamic_printk_init);
-/* may want to move this earlier so we can get traces as early as possible */
-
-static int __init dynamic_printk_setup(char *str)
-{
-	if (str)
-		return -ENOENT;
-	dynamic_enabled = DYNAMIC_ENABLED_ALL;
-	return 0;
-}
-/* Use early_param(), so we can get debug output as early as possible */
-early_param("dynamic_printk", dynamic_printk_setup);