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Subject[PATCH 4/5] tracing/core: drop the old ftrace_printk implementation in favour of ftrace_bprintk
Impact: faster and lighter tracing

Now that we have ftrace_bprintk() which is faster and consume lesser
memory than ftrace_printk() and has the same purpose, we can now drop
the old implementation in favour of the binary one from ftrace_bprintk(),
which means we move all the implementation of ftrace_bprintk() to
ftrace_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, ftrace_bprintk depended of a single tracer and couldn't
work without. This tracer has been dropped and the whole implementation
of ftrace_printk() (like the module formats management) is now integrated
in the tracing core (comes with CONFIG_TRACING), though we keep the file
trace_bprintk (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 ftrace_printk/ftrace_vprintk macros to support non-builtin formats
constants, and fix 'const' qualifiers warnings. But this is all transparent for
developers.

- etc...

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
include/linux/ftrace.h | 68 ++++----
include/linux/module.h | 2 +-
kernel/trace/Kconfig | 7 +-
kernel/trace/Makefile | 2 +-
kernel/trace/trace.c | 209 +++++++---------------
kernel/trace/trace.h | 14 +--
kernel/trace/trace_functions_graph.c | 6 +-
kernel/trace/trace_mmiotrace.c | 9 +-
kernel/trace/trace_output.c | 69 +------
kernel/trace/trace_output.h | 2 +
kernel/trace/{trace_bprintk.c => trace_printk.c} | 113 ++++--------
11 files changed, 162 insertions(+), 339 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index f82b986..696a09b 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -222,31 +222,6 @@ 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 __ftrace_bprintk(unsigned long ip, const char *fmt, ...)
- __attribute__ ((format (printf, 2, 3)));
-
-static inline void ____ftrace_bprintk_check_format(const char *fmt, ...)
- __attribute__ ((format (printf, 1, 2)));
-static inline void ____ftrace_bprintk_check_format(const char *fmt, ...) {}
-#define __ftrace_bprintk_check_format(fmt, args...) \
-do { \
- if (0) \
- ____ftrace_bprintk_check_format(fmt, ##args); \
-} while (0)
-
-#define ftrace_bprintk(fmt, args...) \
-do { \
- static char *__attribute__((section("__trace_bprintk_fmt"))) \
- ftrace_bprintk_fmt = fmt; \
- __ftrace_bprintk_check_format(fmt, ##args); \
- __ftrace_bprintk(_THIS_IP_, ftrace_bprintk_fmt, ##args); \
-} while (0)
-#else
-#define ftrace_bprintk ftrace_printk
-#endif
-
/* May be defined in arch */
extern int ftrace_arch_read_dyn_info(char *buf, int size);

@@ -367,15 +342,40 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
* Please refrain from leaving ftrace_printks scattered around in
* your code.
*/
-# define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
-extern int
-__ftrace_printk(unsigned long ip, const char *fmt, ...)
- __attribute__ ((format (printf, 2, 3)));
-# define ftrace_vprintk(fmt, ap) __ftrace_printk(_THIS_IP_, fmt, ap)
-extern int
-__ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap);
+extern int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list args);
+extern int __ftrace_printk(unsigned long ip, const char *fmt, ...)
+ __attribute__ ((format (printf, 2, 3)));
+
+static inline void ____ftrace_printk_check_format(const char *fmt, ...)
+ __attribute__ ((format (printf, 1, 2)));
+static inline void ____ftrace_printk_check_format(const char *fmt, ...) {}
+#define __ftrace_printk_check_format(fmt, args...) \
+do { \
+ if (0) \
+ ____ftrace_printk_check_format(fmt, ##args); \
+} while (0)
+
+#define ftrace_vprintk(fmt, vargs) \
+do { \
+ static const char *ftrace_printk_fmt \
+ __attribute__((section("__trace_bprintk_fmt"))); \
+ ftrace_printk_fmt = fmt; \
+ __ftrace_vprintk(_THIS_IP_, ftrace_printk_fmt, vargs); \
+} while (0)
+
+#define ftrace_printk(fmt, args...) \
+do { \
+ static const char *ftrace_printk_fmt \
+ __attribute__((section("__trace_bprintk_fmt"))); \
+ ftrace_printk_fmt = fmt; \
+ __ftrace_printk_check_format(fmt, ##args); \
+ __ftrace_printk(_THIS_IP_, ftrace_printk_fmt, ##args); \
+} while (0)
+
extern void ftrace_dump(void);
-#else
+
+#else /* !CONFIG_TRACING */
+
static inline void
ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
static inline int
@@ -395,7 +395,7 @@ ftrace_vprintk(const char *fmt, va_list ap)
return 0;
}
static inline void ftrace_dump(void) { }
-#endif
+#endif /* CONFIG_TRACING */

#ifdef CONFIG_FTRACE_MCOUNT_RECORD
extern void ftrace_init(void);
diff --git a/include/linux/module.h b/include/linux/module.h
index c4f2845..e418da1 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -347,7 +347,7 @@ 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
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 2e84fc7..52439c8 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -52,6 +52,7 @@ config TRACING
select STACKTRACE if STACKTRACE_SUPPORT
select TRACEPOINTS
select NOP_TRACER
+ select BINARY_PRINTF

menu "Tracers"

@@ -86,12 +87,6 @@ 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
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index dba6157..25e243f 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -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
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0e30dce..2ad285b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1171,6 +1171,67 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

+
+/**
+ * trace_vprintk - write binary msg to tracing buffer
+ *
+ * Caller must insure @fmt are valid when msg is in 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 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();
+ preempt_disable_notrace();
+ 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:
+ preempt_enable_notrace();
+ unpause_graph_tracing();
+
+ return len;
+}
+EXPORT_SYMBOL_GPL(trace_vprintk);
+
enum trace_file_type {
TRACE_FILE_LAT_FMT = 1,
TRACE_FILE_ANNOTATE = 2,
@@ -1588,7 +1649,7 @@ 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;

@@ -3496,152 +3557,6 @@ static __init int tracer_init_debugfs(void)
return 0;
}

-int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
-{
- static DEFINE_SPINLOCK(trace_buf_lock);
- 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();
- spin_lock_irqsave(&trace_buf_lock, irq_flags);
- 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:
- spin_unlock_irqrestore(&trace_buf_lock, irq_flags);
- unpause_graph_tracing();
- out:
- preempt_enable_notrace();
-
- return len;
-}
-EXPORT_SYMBOL_GPL(trace_vprintk);
-
-int __ftrace_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(__ftrace_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 cpu, len = 0, size, pc;
-
- if (tracing_disabled || !trace_bprintk_enable)
- 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;
-
- 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:
- preempt_enable_notrace();
-
- return len;
-}
-EXPORT_SYMBOL_GPL(trace_vbprintk);
-
-int __ftrace_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(__ftrace_bprintk);
-
static int trace_panic_handler(struct notifier_block *this,
unsigned long event, void *unused)
{
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 92703b1..0ccc678 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -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;
@@ -295,7 +288,6 @@ 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); \
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 2461732..13e362d 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -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;

diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index c401b90..23e346a 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -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;

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 7897b5d..a020a9b 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -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;
@@ -876,50 +875,6 @@ static enum print_line_t trace_print_print(struct trace_iterator *iter,
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,
- .latency_trace = trace_print_print,
- .raw = trace_print_raw,
-};
-
-/* TRACE_BPRINTK */
-static enum print_line_t
-trace_bprintk_print(struct trace_iterator *iter, int flags)
-{
- struct trace_entry *entry = iter->ent;
- struct trace_seq *s = &iter->seq;
- struct bprintk_entry *field;
-
- trace_assign_type(field, entry);
-
- if (!seq_print_ip_sym(s, field->ip, flags))
- goto partial;
-
if (!trace_seq_puts(s, ": "))
goto partial;

@@ -932,14 +887,13 @@ 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;
@@ -953,13 +907,11 @@ 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,
- .latency_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,
+ .latency_trace = trace_print_print,
+ .raw = trace_print_raw,
};

static struct trace_event *events[] __initdata = {
@@ -970,7 +922,6 @@ static struct trace_event *events[] __initdata = {
&trace_stack_event,
&trace_user_stack_event,
&trace_print_event,
- &trace_bprintk_event,
NULL
};

diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
index 551a25a..6d39010 100644
--- a/kernel/trace/trace_output.h
+++ b/kernel/trace/trace_output.h
@@ -19,6 +19,8 @@ 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,
diff --git a/kernel/trace/trace_bprintk.c b/kernel/trace/trace_printk.c
similarity index 65%
rename from kernel/trace/trace_bprintk.c
rename to kernel/trace/trace_printk.c
index 28e6286..09f4ace 100644
--- a/kernel/trace/trace_bprintk.c
+++ b/kernel/trace/trace_printk.c
@@ -21,32 +21,21 @@

#ifdef CONFIG_MODULES

-/* binary printk basic */
-static DEFINE_MUTEX(btrace_mutex);
-static int btrace_metadata_count;
/*
- * modules ftrace_bprintk()'s formats are autosaved in struct trace_bprintk_fmt
+ * modules ftrace_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;
int count;
char fmt[0];
};

-
-static inline void lock_btrace(void)
-{
- mutex_lock(&btrace_mutex);
-}
-
-static inline void unlock_btrace(void)
-{
- mutex_unlock(&btrace_mutex);
-}
-
/*
* If trace_bprintk() is not active, we release the trace_bprintk's
* formats that no modules has reference to.
@@ -76,7 +65,8 @@ 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) {
@@ -95,14 +85,15 @@ void hold_module_trace_bprintk_format(const char **start, const char **end)
} else
*iter = NULL;
}
- unlock_btrace();
+ mutex_unlock(&btrace_mutex);
}

static
void release_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;
if (!*iter)
@@ -110,12 +101,12 @@ void release_module_trace_bprintk_format(const char **start, const char **end)

tb_fmt = container_of(*iter, struct trace_bprintk_fmt, fmt[0]);
tb_fmt->count--;
- if (!tb_fmt->count && !btrace_metadata_count) {
+ if (!tb_fmt->count) {
list_del(&tb_fmt->list);
kfree(tb_fmt);
}
}
- unlock_btrace();
+ mutex_unlock(&btrace_mutex);
}

static int module_trace_bprintk_format_notify(struct notifier_block *self,
@@ -134,24 +125,6 @@ static int module_trace_bprintk_format_notify(struct notifier_block *self,
return 0;
}

-static void get_btrace_metadata(void)
-{
- lock_btrace();
- btrace_metadata_count++;
- unlock_btrace();
-}
-
-static void put_btrace_metadata(void)
-{
- lock_btrace();
- btrace_metadata_count--;
-
- if (!btrace_metadata_count) {
- shrink_trace_bprintk_fmt();
- }
- unlock_btrace();
-}
-
#else /* !CONFIG_MODULES */
__init static int
module_trace_bprintk_format_notify(struct notifier_block *self,
@@ -159,9 +132,6 @@ module_trace_bprintk_format_notify(struct notifier_block *self,
{
return 0;
}
-
-static inline void get_btrace_metadata(void) { }
-static inline void put_btrace_metadata(void) { }
#endif /* CONFIG_MODULES */


@@ -170,48 +140,39 @@ struct notifier_block module_trace_bprintk_format_nb = {
.notifier_call = module_trace_bprintk_format_notify,
};

-/* events tracer */
-int trace_bprintk_enable;
-
-static void start_bprintk_trace(struct trace_array *tr)
+int __ftrace_printk(unsigned long ip, const char *fmt, ...)
{
- get_btrace_metadata();
- tracing_reset_online_cpus(tr);
- trace_bprintk_enable = 1;
-}
+ int ret;
+ va_list ap;

-static void stop_bprintk_trace(struct trace_array *tr)
-{
- trace_bprintk_enable = 0;
- tracing_reset_online_cpus(tr);
- put_btrace_metadata();
-}
+ if (unlikely(!fmt))
+ return 0;

-static int init_bprintk_trace(struct trace_array *tr)
-{
- start_bprintk_trace(tr);
- return 0;
+ 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(__ftrace_printk);

-static struct tracer bprintk_trace __read_mostly =
+int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
{
- .name = "events",
- .init = init_bprintk_trace,
- .reset = stop_bprintk_trace,
- .start = start_bprintk_trace,
- .stop = stop_bprintk_trace,
-};
+ if (unlikely(!fmt))
+ return 0;

-static __init int init_bprintk(void)
-{
- int ret = register_module_notifier(&module_trace_bprintk_format_nb);
- if (ret)
- return ret;
+ if (!(trace_flags & TRACE_ITER_PRINTK))
+ return 0;

- ret = register_tracer(&bprintk_trace);
- if (ret)
- unregister_module_notifier(&module_trace_bprintk_format_nb);
- return ret;
+ return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
}
+EXPORT_SYMBOL_GPL(__ftrace_vprintk);
+

-device_initcall(init_bprintk);
+static __init int init_trace_printk(void)
+{
+ return register_module_notifier(&module_trace_bprintk_format_nb);
+}
+early_initcall(init_trace_printk);
--
1.6.1



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