tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk()
authorFrederic Weisbecker <fweisbec@gmail.com>
Fri, 6 Mar 2009 16:21:49 +0000 (17:21 +0100)
committerIngo Molnar <mingo@elte.hu>
Fri, 6 Mar 2009 16:59:12 +0000 (17:59 +0100)
Impact: faster and lighter tracing

Now that we have trace_bprintk() which is faster and consume lesser
memory than trace_printk() and has the same purpose, we can now drop
the old implementation in favour of the binary one from trace_bprintk(),
which means we move all the implementation of trace_bprintk() to
trace_printk(), so the Api doesn't change except that we must now use
trace_seq_bprintk() to print the TRACE_PRINT entries.

Some changes result of this:

- Previously, trace_bprintk depended of a single tracer and couldn't
  work without. This tracer has been dropped and the whole implementation
  of trace_printk() (like the module formats management) is now integrated
  in the tracing core (comes with CONFIG_TRACING), though we keep the file
  trace_printk (previously trace_bprintk.c) where we can find the module
  management. Thus we don't overflow trace.c

- changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries.

- change a bit trace_printk/trace_vprintk macros to support non-builtin formats
  constants, and fix 'const' qualifiers warnings. But this is all transparent for
  developers.

- etc...

V2:

- Rebase against last changes
- Fix mispell on the changelog

V3:

- Rebase against last changes (moving trace_printk() to kernel.h)

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
12 files changed:
include/linux/ftrace.h
include/linux/kernel.h
include/linux/module.h
kernel/trace/Kconfig
kernel/trace/Makefile
kernel/trace/trace.c
kernel/trace/trace.h
kernel/trace/trace_functions_graph.c
kernel/trace/trace_mmiotrace.c
kernel/trace/trace_output.c
kernel/trace/trace_output.h
kernel/trace/trace_printk.c [moved from kernel/trace/trace_bprintk.c with 66% similarity]

index 1cc8ca4..e1583f2 100644 (file)
@@ -223,31 +223,6 @@ extern int ftrace_make_nop(struct module *mod,
  */
 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 
-#ifdef CONFIG_TRACE_BPRINTK
-extern int trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
-extern int __trace_bprintk(unsigned long ip, const char *fmt, ...)
-               __attribute__ ((format (printf, 2, 3)));
-
-static inline void  ____trace_bprintk_check_format(const char *fmt, ...)
-               __attribute__ ((format (printf, 1, 2)));
-static inline void ____trace_bprintk_check_format(const char *fmt, ...) {}
-#define __trace_bprintk_check_format(fmt, args...)                     \
-do {                                                                   \
-       if (0)                                                          \
-               ____trace_bprintk_check_format(fmt, ##args);            \
-} while (0)
-
-#define trace_bprintk(fmt, args...)                                    \
-do {                                                                   \
-       static char *__attribute__((section("__trace_bprintk_fmt")))    \
-                       trace_bprintk_fmt = fmt;                        \
-       __trace_bprintk_check_format(fmt, ##args);                      \
-       __trace_bprintk(_THIS_IP_, trace_bprintk_fmt, ##args);  \
-} while (0)
-#else
-#define trace_bprintk trace_printk
-#endif
-
 /* May be defined in arch */
 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 
index 7aef15c..4e726b9 100644 (file)
@@ -423,6 +423,16 @@ extern void ftrace_off_permanent(void);
 extern void
 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
 
+static inline void __attribute__ ((format (printf, 1, 2)))
+____trace_printk_check_format(const char *fmt, ...)
+{
+}
+#define __trace_printk_check_format(fmt, args...)                      \
+do {                                                                   \
+       if (0)                                                          \
+               ____trace_printk_check_format(fmt, ##args);             \
+} while (0)
+
 /**
  * trace_printk - printf formatting in the ftrace buffer
  * @fmt: the printf format for printing
@@ -439,13 +449,31 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
  * Please refrain from leaving trace_printks scattered around in
  * your code.
  */
-# define trace_printk(fmt...) __trace_printk(_THIS_IP_, fmt)
+
+#define trace_printk(fmt, args...)                                     \
+do {                                                                   \
+       static const char *trace_printk_fmt                             \
+       __attribute__((section("__trace_printk_fmt")));                 \
+       trace_printk_fmt = fmt;                                 \
+       __trace_printk_check_format(fmt, ##args);                       \
+       __trace_printk(_THIS_IP_, trace_printk_fmt, ##args);            \
+} while (0)
+
 extern int
 __trace_printk(unsigned long ip, const char *fmt, ...)
        __attribute__ ((format (printf, 2, 3)));
-# define ftrace_vprintk(fmt, ap) __trace_printk(_THIS_IP_, fmt, ap)
+
+#define ftrace_vprintk(fmt, vargs)                                     \
+do {                                                                   \
+       static const char *trace_printk_fmt                             \
+       __attribute__((section("__trace_printk_fmt")));                 \
+       trace_printk_fmt = fmt;                                 \
+       __ftrace_vprintk(_THIS_IP_, trace_printk_fmt, vargs);           \
+} while (0)
+
 extern int
 __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
+
 extern void ftrace_dump(void);
 #else
 static inline void
@@ -467,7 +495,7 @@ ftrace_vprintk(const char *fmt, va_list ap)
        return 0;
 }
 static inline void ftrace_dump(void) { }
-#endif
+#endif /* CONFIG_TRACING */
 
 /*
  *      Display an IP address in readable format.
index 8cbec97..22d9878 100644 (file)
@@ -329,7 +329,7 @@ struct module
        unsigned int num_tracepoints;
 #endif
 
-#ifdef CONFIG_TRACE_BPRINTK
+#ifdef CONFIG_TRACING
        const char **trace_bprintk_fmt_start;
        unsigned int num_trace_bprintk_fmt;
 #endif
index ad8d361..8e4a2a6 100644 (file)
@@ -52,6 +52,7 @@ config TRACING
        select STACKTRACE if STACKTRACE_SUPPORT
        select TRACEPOINTS
        select NOP_TRACER
+       select BINARY_PRINTF
 
 #
 # Minimum requirements an architecture has to meet for us to
@@ -97,12 +98,6 @@ config FUNCTION_GRAPH_TRACER
          This is done by setting the current return address on the current
          task structure into a stack of calls.
 
-config TRACE_BPRINTK
-       bool "Binary printk for tracing"
-       default y
-       depends on TRACING
-       select BINARY_PRINTF
-
 config IRQSOFF_TRACER
        bool "Interrupts-off Latency Tracer"
        default n
index 46557ef..c7a2943 100644 (file)
@@ -22,7 +22,7 @@ obj-$(CONFIG_TRACING) += trace.o
 obj-$(CONFIG_TRACING) += trace_clock.o
 obj-$(CONFIG_TRACING) += trace_output.o
 obj-$(CONFIG_TRACING) += trace_stat.o
-obj-$(CONFIG_TRACE_BPRINTK) += trace_bprintk.o
+obj-$(CONFIG_TRACING) += trace_printk.o
 obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
 obj-$(CONFIG_SYSPROF_TRACER) += trace_sysprof.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
index 46b3cd7..cc94f86 100644 (file)
@@ -1169,6 +1169,67 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
+
+/**
+ * trace_vprintk - write binary msg to tracing buffer
+ *
+ */
+int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
+{
+       static DEFINE_SPINLOCK(trace_buf_lock);
+       static u32 trace_buf[TRACE_BUF_SIZE];
+
+       struct ring_buffer_event *event;
+       struct trace_array *tr = &global_trace;
+       struct trace_array_cpu *data;
+       struct print_entry *entry;
+       unsigned long flags;
+       int resched;
+       int cpu, len = 0, size, pc;
+
+       if (unlikely(tracing_selftest_running || tracing_disabled))
+               return 0;
+
+       /* Don't pollute graph traces with trace_vprintk internals */
+       pause_graph_tracing();
+
+       pc = preempt_count();
+       resched = ftrace_preempt_disable();
+       cpu = raw_smp_processor_id();
+       data = tr->data[cpu];
+
+       if (unlikely(atomic_read(&data->disabled)))
+               goto out;
+
+       spin_lock_irqsave(&trace_buf_lock, flags);
+       len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
+
+       if (len > TRACE_BUF_SIZE || len < 0)
+               goto out_unlock;
+
+       size = sizeof(*entry) + sizeof(u32) * len;
+       event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, flags, pc);
+       if (!event)
+               goto out_unlock;
+       entry = ring_buffer_event_data(event);
+       entry->ip                       = ip;
+       entry->depth                    = depth;
+       entry->fmt                      = fmt;
+
+       memcpy(entry->buf, trace_buf, sizeof(u32) * len);
+       ring_buffer_unlock_commit(tr->buffer, event);
+
+out_unlock:
+       spin_unlock_irqrestore(&trace_buf_lock, flags);
+
+out:
+       ftrace_preempt_enable(resched);
+       unpause_graph_tracing();
+
+       return len;
+}
+EXPORT_SYMBOL_GPL(trace_vprintk);
+
 enum trace_file_type {
        TRACE_FILE_LAT_FMT      = 1,
        TRACE_FILE_ANNOTATE     = 2,
@@ -1564,7 +1625,7 @@ static enum print_line_t print_printk_msg_only(struct trace_iterator *iter)
 
        trace_assign_type(field, entry);
 
-       ret = trace_seq_printf(s, "%s", field->buf);
+       ret = trace_seq_bprintf(s, field->fmt, field->buf);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;
 
@@ -3714,155 +3775,6 @@ static __init int tracer_init_debugfs(void)
        return 0;
 }
 
-int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
-{
-       static raw_spinlock_t trace_buf_lock = __RAW_SPIN_LOCK_UNLOCKED;
-       static char trace_buf[TRACE_BUF_SIZE];
-
-       struct ring_buffer_event *event;
-       struct trace_array *tr = &global_trace;
-       struct trace_array_cpu *data;
-       int cpu, len = 0, size, pc;
-       struct print_entry *entry;
-       unsigned long irq_flags;
-
-       if (tracing_disabled || tracing_selftest_running)
-               return 0;
-
-       pc = preempt_count();
-       preempt_disable_notrace();
-       cpu = raw_smp_processor_id();
-       data = tr->data[cpu];
-
-       if (unlikely(atomic_read(&data->disabled)))
-               goto out;
-
-       pause_graph_tracing();
-       raw_local_irq_save(irq_flags);
-       __raw_spin_lock(&trace_buf_lock);
-       len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
-
-       len = min(len, TRACE_BUF_SIZE-1);
-       trace_buf[len] = 0;
-
-       size = sizeof(*entry) + len + 1;
-       event = trace_buffer_lock_reserve(tr, TRACE_PRINT, size, irq_flags, pc);
-       if (!event)
-               goto out_unlock;
-       entry = ring_buffer_event_data(event);
-       entry->ip                       = ip;
-       entry->depth                    = depth;
-
-       memcpy(&entry->buf, trace_buf, len);
-       entry->buf[len] = 0;
-       ring_buffer_unlock_commit(tr->buffer, event);
-
- out_unlock:
-       __raw_spin_unlock(&trace_buf_lock);
-       raw_local_irq_restore(irq_flags);
-       unpause_graph_tracing();
- out:
-       preempt_enable_notrace();
-
-       return len;
-}
-EXPORT_SYMBOL_GPL(trace_vprintk);
-
-int __trace_printk(unsigned long ip, const char *fmt, ...)
-{
-       int ret;
-       va_list ap;
-
-       if (!(trace_flags & TRACE_ITER_PRINTK))
-               return 0;
-
-       va_start(ap, fmt);
-       ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
-       va_end(ap);
-       return ret;
-}
-EXPORT_SYMBOL_GPL(__trace_printk);
-
-int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
-{
-       if (!(trace_flags & TRACE_ITER_PRINTK))
-               return 0;
-
-       return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
-}
-EXPORT_SYMBOL_GPL(__ftrace_vprintk);
-
-/**
- * trace_vbprintk - write binary msg to tracing buffer
- *
- * Caller must insure @fmt are valid when msg is in tracing buffer.
- */
-int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
-{
-       static DEFINE_SPINLOCK(trace_buf_lock);
-       static u32 trace_buf[TRACE_BUF_SIZE];
-
-       struct ring_buffer_event *event;
-       struct trace_array *tr = &global_trace;
-       struct trace_array_cpu *data;
-       struct bprintk_entry *entry;
-       unsigned long flags;
-       int resched;
-       int cpu, len = 0, size, pc;
-
-       if (tracing_disabled || !trace_bprintk_enable)
-               return 0;
-
-       pc = preempt_count();
-       resched = ftrace_preempt_disable();
-       cpu = raw_smp_processor_id();
-       data = tr->data[cpu];
-
-       if (unlikely(atomic_read(&data->disabled)))
-               goto out;
-
-       spin_lock_irqsave(&trace_buf_lock, flags);
-       len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
-
-       if (len > TRACE_BUF_SIZE || len < 0)
-               goto out_unlock;
-
-       size = sizeof(*entry) + sizeof(u32) * len;
-       event = trace_buffer_lock_reserve(tr, TRACE_BPRINTK, size, flags, pc);
-       if (!event)
-               goto out_unlock;
-       entry = ring_buffer_event_data(event);
-       entry->ip                       = ip;
-       entry->fmt                      = fmt;
-
-       memcpy(entry->buf, trace_buf, sizeof(u32) * len);
-       ring_buffer_unlock_commit(tr->buffer, event);
-
-out_unlock:
-       spin_unlock_irqrestore(&trace_buf_lock, flags);
-
-out:
-       ftrace_preempt_enable(resched);
-
-       return len;
-}
-EXPORT_SYMBOL_GPL(trace_vbprintk);
-
-int __trace_bprintk(unsigned long ip, const char *fmt, ...)
-{
-       int ret;
-       va_list ap;
-
-       if (!fmt)
-               return 0;
-
-       va_start(ap, fmt);
-       ret = trace_vbprintk(ip, fmt, ap);
-       va_end(ap);
-       return ret;
-}
-EXPORT_SYMBOL_GPL(__trace_bprintk);
-
 static int trace_panic_handler(struct notifier_block *this,
                               unsigned long event, void *unused)
 {
index 0f5077f..6140922 100644 (file)
@@ -20,7 +20,6 @@ enum trace_type {
        TRACE_WAKE,
        TRACE_STACK,
        TRACE_PRINT,
-       TRACE_BPRINTK,
        TRACE_SPECIAL,
        TRACE_MMIO_RW,
        TRACE_MMIO_MAP,
@@ -120,16 +119,10 @@ struct userstack_entry {
  */
 struct print_entry {
        struct trace_entry      ent;
-       unsigned long           ip;
+       unsigned long           ip;
        int                     depth;
-       char                    buf[];
-};
-
-struct bprintk_entry {
-       struct trace_entry ent;
-       unsigned long ip;
-       const char *fmt;
-       u32 buf[];
+       const char              *fmt;
+       u32                     buf[];
 };
 #ifdef CONFIG_TRACE_BPRINTK
 extern int trace_bprintk_enable;
@@ -296,7 +289,6 @@ extern void __ftrace_bad_type(void);
                IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);   \
                IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
                IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);   \
-               IF_ASSIGN(var, ent, struct bprintk_entry, TRACE_BPRINTK);\
                IF_ASSIGN(var, ent, struct special_entry, 0);           \
                IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,          \
                          TRACE_MMIO_RW);                               \
index e527f2f..453ebd3 100644 (file)
@@ -742,7 +742,11 @@ print_graph_comment(struct print_entry *trace, struct trace_seq *s,
                }
 
        /* The comment */
-       ret = trace_seq_printf(s, "/* %s", trace->buf);
+       ret = trace_seq_printf(s, "/* ");
+       if (!ret)
+               return TRACE_TYPE_PARTIAL_LINE;
+
+       ret = trace_seq_bprintf(s, trace->fmt, trace->buf);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;
 
index c401b90..23e346a 100644 (file)
@@ -254,15 +254,18 @@ static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 {
        struct trace_entry *entry = iter->ent;
        struct print_entry *print = (struct print_entry *)entry;
-       const char *msg         = print->buf;
        struct trace_seq *s     = &iter->seq;
        unsigned long long t    = ns2usecs(iter->ts);
-       unsigned long usec_rem  = do_div(t, 1000000ULL);
+       unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
        unsigned secs           = (unsigned long)t;
        int ret;
 
        /* The trailing newline must be in the message. */
-       ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
+       ret = trace_seq_printf(s, "MARK %u.%06lu ", secs, usec_rem);
+       if (!ret)
+               return TRACE_TYPE_PARTIAL_LINE;
+
+       ret = trace_seq_bprintf(s, print->fmt, print->buf);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;
 
index 4ab7120..ef8fd66 100644 (file)
@@ -53,8 +53,7 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
        return len;
 }
 
-static int
-trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
+int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 {
        int len = (PAGE_SIZE - 1) - s->len;
        int ret;
@@ -834,54 +833,12 @@ static struct trace_event trace_user_stack_event = {
 };
 
 /* TRACE_PRINT */
-static enum print_line_t trace_print_print(struct trace_iterator *iter,
-                                          int flags)
-{
-       struct print_entry *field;
-       struct trace_seq *s = &iter->seq;
-
-       trace_assign_type(field, iter->ent);
-
-       if (!seq_print_ip_sym(s, field->ip, flags))
-               goto partial;
-
-       if (!trace_seq_printf(s, ": %s", field->buf))
-               goto partial;
-
-       return TRACE_TYPE_HANDLED;
-
- partial:
-       return TRACE_TYPE_PARTIAL_LINE;
-}
-
-static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags)
-{
-       struct print_entry *field;
-
-       trace_assign_type(field, iter->ent);
-
-       if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
-               goto partial;
-
-       return TRACE_TYPE_HANDLED;
-
- partial:
-       return TRACE_TYPE_PARTIAL_LINE;
-}
-
-static struct trace_event trace_print_event = {
-       .type           = TRACE_PRINT,
-       .trace          = trace_print_print,
-       .raw            = trace_print_raw,
-};
-
-/* TRACE_BPRINTK */
 static enum print_line_t
-trace_bprintk_print(struct trace_iterator *iter, int flags)
+trace_print_print(struct trace_iterator *iter, int flags)
 {
        struct trace_entry *entry = iter->ent;
        struct trace_seq *s = &iter->seq;
-       struct bprintk_entry *field;
+       struct print_entry *field;
 
        trace_assign_type(field, entry);
 
@@ -900,14 +857,13 @@ trace_bprintk_print(struct trace_iterator *iter, int flags)
        return TRACE_TYPE_PARTIAL_LINE;
 }
 
-static enum print_line_t
-trace_bprintk_raw(struct trace_iterator *iter, int flags)
+
+static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags)
 {
-       struct trace_entry *entry = iter->ent;
+       struct print_entry *field;
        struct trace_seq *s = &iter->seq;
-       struct bprintk_entry *field;
 
-       trace_assign_type(field, entry);
+       trace_assign_type(field, iter->ent);
 
        if (!trace_seq_printf(s, ": %lx : ", field->ip))
                goto partial;
@@ -921,12 +877,11 @@ trace_bprintk_raw(struct trace_iterator *iter, int flags)
        return TRACE_TYPE_PARTIAL_LINE;
 }
 
-static struct trace_event trace_bprintk_event = {
-       .type           = TRACE_BPRINTK,
-       .trace          = trace_bprintk_print,
-       .raw            = trace_bprintk_raw,
-       .hex            = trace_nop_print,
-       .binary         = trace_nop_print,
+
+static struct trace_event trace_print_event = {
+       .type           = TRACE_PRINT,
+       .trace          = trace_print_print,
+       .raw            = trace_print_raw,
 };
 
 static struct trace_event *events[] __initdata = {
@@ -937,7 +892,6 @@ static struct trace_event *events[] __initdata = {
        &trace_stack_event,
        &trace_user_stack_event,
        &trace_print_event,
-       &trace_bprintk_event,
        NULL
 };
 
index 8a34d68..3b90e6a 100644 (file)
@@ -18,6 +18,8 @@ struct trace_event {
 extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
        __attribute__ ((format (printf, 2, 3)));
 extern int
+trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
+extern int
 seq_print_ip_sym(struct trace_seq *s, unsigned long ip,
                unsigned long sym_flags);
 extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
similarity index 66%
rename from kernel/trace/trace_bprintk.c
rename to kernel/trace/trace_printk.c
index f4c245a..a50aea2 100644 (file)
 
 #ifdef CONFIG_MODULES
 
-/* binary printk basic */
-static DEFINE_MUTEX(btrace_mutex);
 /*
- * modules trace_bprintk()'s formats are autosaved in struct trace_bprintk_fmt
+ * modules trace_printk()'s formats are autosaved in struct trace_bprintk_fmt
  * which are queued on trace_bprintk_fmt_list.
  */
 static LIST_HEAD(trace_bprintk_fmt_list);
 
+/* serialize accesses to trace_bprintk_fmt_list */
+static DEFINE_MUTEX(btrace_mutex);
+
 struct trace_bprintk_fmt {
        struct list_head list;
        char fmt[0];
 };
 
-
-static inline void lock_btrace(void)
-{
-       mutex_lock(&btrace_mutex);
-}
-
-static inline void unlock_btrace(void)
-{
-       mutex_unlock(&btrace_mutex);
-}
-
-
 static inline struct trace_bprintk_fmt *lookup_format(const char *fmt)
 {
        struct trace_bprintk_fmt *pos;
@@ -60,7 +49,8 @@ static
 void hold_module_trace_bprintk_format(const char **start, const char **end)
 {
        const char **iter;
-       lock_btrace();
+
+       mutex_lock(&btrace_mutex);
        for (iter = start; iter < end; iter++) {
                struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);
                if (tb_fmt) {
@@ -77,7 +67,7 @@ void hold_module_trace_bprintk_format(const char **start, const char **end)
                } else
                        *iter = NULL;
        }
-       unlock_btrace();
+       mutex_unlock(&btrace_mutex);
 }
 
 static int module_trace_bprintk_format_notify(struct notifier_block *self,
@@ -109,46 +99,40 @@ struct notifier_block module_trace_bprintk_format_nb = {
        .notifier_call = module_trace_bprintk_format_notify,
 };
 
-/* events tracer */
-int trace_bprintk_enable;
+int __trace_printk(unsigned long ip, const char *fmt, ...)
+ {
+       int ret;
+       va_list ap;
 
-static void start_bprintk_trace(struct trace_array *tr)
-{
-       tracing_reset_online_cpus(tr);
-       trace_bprintk_enable = 1;
-}
+       if (unlikely(!fmt))
+               return 0;
 
-static void stop_bprintk_trace(struct trace_array *tr)
-{
-       trace_bprintk_enable = 0;
-       tracing_reset_online_cpus(tr);
+       if (!(trace_flags & TRACE_ITER_PRINTK))
+               return 0;
+
+       va_start(ap, fmt);
+       ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
+       va_end(ap);
+       return ret;
 }
+EXPORT_SYMBOL_GPL(__trace_printk);
 
-static int init_bprintk_trace(struct trace_array *tr)
-{
-       start_bprintk_trace(tr);
-       return 0;
+int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
+ {
+       if (unlikely(!fmt))
+               return 0;
+
+       if (!(trace_flags & TRACE_ITER_PRINTK))
+               return 0;
+
+       return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
 }
+EXPORT_SYMBOL_GPL(__ftrace_vprintk);
 
-static struct tracer bprintk_trace __read_mostly =
-{
-       .name        = "events",
-       .init        = init_bprintk_trace,
-       .reset       = stop_bprintk_trace,
-       .start       = start_bprintk_trace,
-       .stop        = stop_bprintk_trace,
-};
 
-static __init int init_bprintk(void)
+static __init int init_trace_printk(void)
 {
-       int ret = register_module_notifier(&module_trace_bprintk_format_nb);
-       if (ret)
-               return ret;
-
-       ret = register_tracer(&bprintk_trace);
-       if (ret)
-               unregister_module_notifier(&module_trace_bprintk_format_nb);
-       return ret;
+       return register_module_notifier(&module_trace_bprintk_format_nb);
 }
 
-device_initcall(init_bprintk);
+early_initcall(init_trace_printk);