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Message-ID: <87k3e29cxz.fsf@sejong.aot.lge.com>
Date: Wed, 15 Jan 2014 11:49:28 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
Frederic Weisbecker <fweisbec@...il.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Ingo Molnar <mingo@...nel.org>,
Namhyung Kim <namhyung.kim@....com>,
LKML <linux-kernel@...r.kernel.org>, Jiri Olsa <jolsa@...hat.com>
Subject: Re: [PATCH 01/17] tools lib traceevent: Add state member to struct trace_seq
Hi Steve,
On Tue, 14 Jan 2014 21:00:58 -0500, Steven Rostedt wrote:
> On Wed, 15 Jan 2014 10:45:24 +0900
> Namhyung Kim <namhyung@...nel.org> wrote:
>
>>
>> @@ -32,8 +33,9 @@
>> #define TRACE_SEQ_POISON ((void *)0xdeadbeef)
>> #define TRACE_SEQ_CHECK(s) \
>> do { \
>> - if ((s)->buffer == TRACE_SEQ_POISON) \
>> - die("Usage of trace_seq after it was destroyed"); \
>> + if (WARN_ONCE((s)->buffer == TRACE_SEQ_POISON, \
>> + "Usage of trace_seq after it was destroyed")) \
>> + (s)->state = TRACE_SEQ__BUFFER_POISONED; \
>> } while (0)
>>
>> @@ -189,9 +205,15 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c)
>> {
>> TRACE_SEQ_CHECK(s);
>>
>> + if (s->state != TRACE_SEQ__GOOD)
>> + return 0;
>> +
>
> Instead of adding all of these, we can extend the macro
> TRACE_SEQ_CHECK() which does a
> if (s->state != TRACE_SEQ__GOOD)
> return;
>
> and a TRACE_SEQ_CHECK_RET() that does a return 0;
Oh, it looks better. But I'd like to TRACE_SEQ_CHECK() as is for some
cases. How about this?
>From 0b43e4f8a9689ab47bdf55d5eddf122f300577e7 Mon Sep 17 00:00:00 2001
From: Namhyung Kim <namhyung@...nel.org>
Date: Thu, 19 Dec 2013 18:17:44 +0900
Subject: [PATCH] tools lib traceevent: Add state member to struct trace_seq
The trace_seq->state is for tracking errors during the use of
trace_seq APIs and getting rid of die() in it.
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
tools/lib/traceevent/Makefile | 2 +-
tools/lib/traceevent/event-parse.h | 7 +++++
tools/lib/traceevent/trace-seq.c | 53 +++++++++++++++++++++++++++++---------
3 files changed, 49 insertions(+), 13 deletions(-)
diff --git a/tools/lib/traceevent/Makefile b/tools/lib/traceevent/Makefile
index f778d48ac609..56d52a33a3df 100644
--- a/tools/lib/traceevent/Makefile
+++ b/tools/lib/traceevent/Makefile
@@ -136,7 +136,7 @@ export Q VERBOSE
EVENT_PARSE_VERSION = $(EP_VERSION).$(EP_PATCHLEVEL).$(EP_EXTRAVERSION)
-INCLUDES = -I. $(CONFIG_INCLUDES)
+INCLUDES = -I. -I $(srctree)/../../include $(CONFIG_INCLUDES)
# Set compile option CFLAGS if not set elsewhere
CFLAGS ?= -g -Wall
diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index cf5db9013f2c..3c890cb28db7 100644
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -58,6 +58,12 @@ struct pevent_record {
#endif
};
+enum trace_seq_fail {
+ TRACE_SEQ__GOOD,
+ TRACE_SEQ__BUFFER_POISONED,
+ TRACE_SEQ__MEM_ALLOC_FAILED,
+};
+
/*
* Trace sequences are used to allow a function to call several other functions
* to create a string of data to use (up to a max of PAGE_SIZE).
@@ -68,6 +74,7 @@ struct trace_seq {
unsigned int buffer_size;
unsigned int len;
unsigned int readpos;
+ enum trace_seq_fail state;
};
void trace_seq_init(struct trace_seq *s);
diff --git a/tools/lib/traceevent/trace-seq.c b/tools/lib/traceevent/trace-seq.c
index d7f2e68bc5b9..c39048b0de08 100644
--- a/tools/lib/traceevent/trace-seq.c
+++ b/tools/lib/traceevent/trace-seq.c
@@ -22,6 +22,7 @@
#include <string.h>
#include <stdarg.h>
+#include <asm/bug.h>
#include "event-parse.h"
#include "event-utils.h"
@@ -32,10 +33,21 @@
#define TRACE_SEQ_POISON ((void *)0xdeadbeef)
#define TRACE_SEQ_CHECK(s) \
do { \
- if ((s)->buffer == TRACE_SEQ_POISON) \
- die("Usage of trace_seq after it was destroyed"); \
+ if (WARN_ONCE((s)->buffer == TRACE_SEQ_POISON, \
+ "Usage of trace_seq after it was destroyed")) \
+ (s)->state = TRACE_SEQ__BUFFER_POISONED; \
} while (0)
+#define TRACE_SEQ_CHECK_RET_N(s, n) \
+do { \
+ TRACE_SEQ_CHECK(s); \
+ if ((s)->state != TRACE_SEQ__GOOD) \
+ return n; \
+} while (0)
+
+#define TRACE_SEQ_CHECK_RET(s) TRACE_SEQ_CHECK_RET_N(s, )
+#define TRACE_SEQ_CHECK_RET0(s) TRACE_SEQ_CHECK_RET_N(s, 0)
+
/**
* trace_seq_init - initialize the trace_seq structure
* @s: a pointer to the trace_seq structure to initialize
@@ -46,6 +58,7 @@ void trace_seq_init(struct trace_seq *s)
s->readpos = 0;
s->buffer_size = TRACE_SEQ_BUF_SIZE;
s->buffer = malloc_or_die(s->buffer_size);
+ s->state = TRACE_SEQ__GOOD;
}
/**
@@ -80,8 +93,9 @@ static void expand_buffer(struct trace_seq *s)
{
s->buffer_size += TRACE_SEQ_BUF_SIZE;
s->buffer = realloc(s->buffer, s->buffer_size);
- if (!s->buffer)
- die("Can't allocate trace_seq buffer memory");
+ if (WARN_ONCE(!s->buffer,
+ "Can't allocate trace_seq buffer memory"))
+ s->state = TRACE_SEQ__MEM_ALLOC_FAILED;
}
/**
@@ -105,9 +119,9 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
int len;
int ret;
- TRACE_SEQ_CHECK(s);
-
try_again:
+ TRACE_SEQ_CHECK_RET0(s);
+
len = (s->buffer_size - 1) - s->len;
va_start(ap, fmt);
@@ -141,9 +155,9 @@ trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
int len;
int ret;
- TRACE_SEQ_CHECK(s);
-
try_again:
+ TRACE_SEQ_CHECK_RET0(s);
+
len = (s->buffer_size - 1) - s->len;
ret = vsnprintf(s->buffer + s->len, len, fmt, args);
@@ -172,13 +186,15 @@ int trace_seq_puts(struct trace_seq *s, const char *str)
{
int len;
- TRACE_SEQ_CHECK(s);
+ TRACE_SEQ_CHECK_RET0(s);
len = strlen(str);
while (len > ((s->buffer_size - 1) - s->len))
expand_buffer(s);
+ TRACE_SEQ_CHECK_RET0(s);
+
memcpy(s->buffer + s->len, str, len);
s->len += len;
@@ -187,11 +203,13 @@ int trace_seq_puts(struct trace_seq *s, const char *str)
int trace_seq_putc(struct trace_seq *s, unsigned char c)
{
- TRACE_SEQ_CHECK(s);
+ TRACE_SEQ_CHECK_RET0(s);
while (s->len >= (s->buffer_size - 1))
expand_buffer(s);
+ TRACE_SEQ_CHECK_RET0(s);
+
s->buffer[s->len++] = c;
return 1;
@@ -199,7 +217,7 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c)
void trace_seq_terminate(struct trace_seq *s)
{
- TRACE_SEQ_CHECK(s);
+ TRACE_SEQ_CHECK_RET(s);
/* There's always one character left on the buffer */
s->buffer[s->len] = 0;
@@ -208,5 +226,16 @@ void trace_seq_terminate(struct trace_seq *s)
int trace_seq_do_printf(struct trace_seq *s)
{
TRACE_SEQ_CHECK(s);
- return printf("%.*s", s->len, s->buffer);
+
+ switch (s->state) {
+ case TRACE_SEQ__GOOD:
+ return printf("%.*s", s->len, s->buffer);
+ case TRACE_SEQ__BUFFER_POISONED:
+ puts("Usage of trace_seq after it was destroyed");
+ break;
+ case TRACE_SEQ__MEM_ALLOC_FAILED:
+ puts("Can't allocate trace_seq buffer memory");
+ break;
+ }
+ return -1;
}
--
1.7.11.7
--
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