[PATCH 2/8] debug printk infrastructure -implement level controls

From: Jason Baron
Date: Thu May 22 2008 - 17:17:40 EST



Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx>
---
include/linux/device.h | 16 ++++++++
include/linux/dynamic_printk.h | 9 +++++
lib/dynamic_printk.c | 78 +++++++++++++++++++++++++++++++++++++--
3 files changed, 99 insertions(+), 4 deletions(-)

diff --git a/include/linux/device.h b/include/linux/device.h
index 8f3ca1f..b1aae4d 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -616,6 +616,22 @@ extern const char *dev_driver_string(struct device *dev);
({ if (0) dev_printk(KERN_DEBUG, dev, format, ##arg); 0; })
#endif

+#ifdef CONFIG_PRINTK_DEBUG
+#define register_dev_dbg_handler(parent, type, max, init) \
+ __register_dev_dbg_handler(KBUILD_MODNAME, parent, type, max, init)
+#define dev_dbg_level(value, dev, format, ...) \
+ __dev_dbg_level(KBUILD_MODNAME, value, dev, format, ##__VA_ARGS__)
+#define dev_dbg_enabled(value) \
+ __dev_dbg_enabled(KBUILD_MODNAME, value)
+#else
+#define register_dev_dbg_handler(parent, type, max, init) \
+ ({ if (0) __register_dev_dbg_handler(KBUILD_MODNAME, parent, type, max, init); 0; })
+#define dev_dbg_level(value, dev, format, ...) \
+ ({ if (0) __dev_dbg_level(KBUILD_MODNAME, value, dev, format, ##__VA_ARGS__); 0; })
+#define dev_dbg_enabled(value) \
+ ({ if (0) __dev_dbg_enabled(KBUILD_MODNAME, value); 0; })
+#endif
+
#ifdef VERBOSE_DEBUG
#define dev_vdbg dev_dbg
#else
diff --git a/include/linux/dynamic_printk.h b/include/linux/dynamic_printk.h
index b1afef3..bb366b4 100644
--- a/include/linux/dynamic_printk.h
+++ b/include/linux/dynamic_printk.h
@@ -7,6 +7,10 @@

#define DYNAMIC_HASH_BITS 5
#define FILE_TABLE_SIZE (1 << DYNAMIC_HASH_BITS)
+#define TYPE_LEVEL 1
+#define TYPE_FLAG 2
+
+struct device;

struct mod_debug {
char *modname;
@@ -40,5 +44,10 @@ static inline unsigned int dynamic_name_hash(char *name)
return (hash & ((1 << DYNAMIC_HASH_BITS) - 1));
}

+int __register_dev_dbg_handler(char *mod_name, char *parent_name, int type, int max,
+ int init);
+void __dev_dbg_level(char *mod_name, int level, struct device *dev, char *fmt, ...);
+int __dev_dbg_enabled(char *modname, int value);
+
#endif
#endif
diff --git a/lib/dynamic_printk.c b/lib/dynamic_printk.c
index 3eaf874..935155c 100644
--- a/lib/dynamic_printk.c
+++ b/lib/dynamic_printk.c
@@ -33,9 +33,10 @@ struct debug_name {
char *name;
unsigned int num_uses;
int enable;
- int flags;
+ int type;
int level;
int ratelimit;
+ struct debug_name *parent;
};

static struct debug_name *find_debug_file(char *module_name)
@@ -117,6 +118,67 @@ int remove_module(char *mod_name)
}
EXPORT_SYMBOL_GPL(remove_module);

+int __register_dev_dbg_handler(char *mod_name, char *parent_name, int type,
+ int max, int init)
+{
+ struct debug_name *elem, *parent;
+
+ elem = find_debug_file(mod_name);
+ if (!elem) {
+ add_module(mod_name);
+ elem = find_debug_file(mod_name);
+ }
+ if (parent_name) {
+ parent = find_debug_file(parent_name);
+ if (!parent) {
+ add_module(parent_name);
+ parent = find_debug_file(parent_name);
+ }
+ elem->parent = parent;
+ return 0;
+ }
+
+ elem->type = type;
+ elem->level = init;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__register_dev_dbg_handler);
+
+int __dev_dbg_enabled(char *mod_name, int value)
+{
+ struct debug_name *elem;
+ int ret = 0;
+
+ if (elem = find_debug_file(mod_name)) {
+ if (elem->parent)
+ elem = elem->parent;
+ if (elem->enable) {
+ if (elem->type == TYPE_LEVEL) {
+ if (value < elem->level)
+ ret = 1;
+ } else if (elem->type == TYPE_FLAG) {
+ if (value & elem->level)
+ ret = 1;
+ }
+ }
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__dev_dbg_enabled);
+
+void __dev_dbg_level(char *mod_name, int level, struct device *dev, char *fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ if (__dev_dbg_enabled(mod_name, level)) {
+ vprintk(fmt, args);
+ }
+ va_end(args);
+}
+EXPORT_SYMBOL_GPL(__dev_dbg_level);
+
+
#ifdef CONFIG_DYNAMIC_PRINTK_DEBUG

void dynamic_printk(char *module_name, char *fmt, ...)
@@ -172,7 +234,7 @@ static int disabled_hash(int i)
static ssize_t pr_debug_write(struct file *file, const char __user *buf,
size_t length, loff_t *ppos)
{
- char *buffer, *s;
+ char *buffer, *s, *level;
int err, hash, i;
struct debug_name *elem;

@@ -230,6 +292,14 @@ static ssize_t pr_debug_write(struct file *file, const char __user *buf,
}
err = 0;
}
+ } else if (!strncmp("set level=", buffer, 10)) {
+ s = buffer + 10;
+ level = strsep(&s, " ");
+ s = strstrip(s);
+ if (elem = find_debug_file(s)) {
+ elem->level = simple_strtol(level, NULL, 10);
+ err = 0;
+ }
}
if (!err)
err = length;
@@ -268,8 +338,8 @@ static int pr_debug_seq_show(struct seq_file *s, void *v)
rcu_read_lock();
head = &module_table[i];
hlist_for_each_entry_rcu(element, node, head, hlist)
- seq_printf(s, "%s %d %d\n", element->name, element->enable,
- element->num_uses);
+ seq_printf(s, "%s %d %d %d\n", element->name, element->enable,
+ element->level, element->num_uses);
rcu_read_unlock();
return 0;
}
--
1.5.4.5

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