[PATCHv2 0/3] tracing - adding common method for reading/parsing user input

[PATCHv2 0/3] tracing - adding common method for reading/parsing user input

[jolsa]

As 3 different places for 4 user input files were using the same way
of reading and parsing user's input, I made one common routine to be
used. 

The mentioned files are:
	set_graph_function
	set_event
	set_ftrace_filter
	set_ftrace_notrace

wbr,
jirka

Signed-off-by: Jiri Olsa <jolsa@redhat.com>

---
 kernel/trace/ftrace.c       |  152 ++++++++++++-------------------------------
 kernel/trace/trace.c        |   83 +++++++++++++++++++++++
 kernel/trace/trace.h        |   48 ++++++++++++++
 kernel/trace/trace_events.c |   58 ++++-------------
 4 files changed, 186 insertions(+), 155 deletions(-)

[PATCHv2 1/3] tracing - buf iterator definition, parsing function

[jolsa]

Defined 'trace_biter' structure to carry the properties of the input,
through the multiple writes.

The 'trace_get_user' reads the user incput string separated by space
(matched by isspace(ch). For each string found the 'struct trace_biter' 
iterator is updated, and the function returns.

wbr,
jirka

Signed-off-by: Jiri Olsa <jolsa@redhat.com>

---
 kernel/trace/trace.c |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++
 kernel/trace/trace.h |   48 +++++++++++++++++++++++++++++
 2 files changed, 131 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index af15008..8cf8f99 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -335,6 +335,89 @@ static struct {
 
 int trace_clock_id;
 
+/*
+ * trace_get_user - reads the user incput string separated by  space
+ * (matched by isspace(ch))
+ *
+ * For each string found the 'struct trace_biter' iterator is updated,
+ * and the function returns.
+ *
+ * Returns number of bytes read.
+ *
+ * see kernel/trace/trace.h for 'struct trace_biter' details.
+ */
+int trace_get_user(struct trace_biter *biter, const char __user *ubuf,
+	size_t cnt, loff_t *ppos)
+{
+	char ch;
+	size_t read = 0;
+	ssize_t ret;
+
+	if (!*ppos)
+		TRACE_BITER_CLEAR(biter);
+
+	ret = get_user(ch, ubuf++);
+	if (ret)
+		goto out;
+
+	read++;
+	cnt--;
+
+	/*
+	 * If the parser haven't finished with the last write,
+	 * continue reading the user input without skipping spaces.
+	 */
+	if (!biter->cont) {
+		/* skip white space */
+		while (cnt && isspace(ch)) {
+			ret = get_user(ch, ubuf++);
+			if (ret)
+				goto out;
+			read++;
+			cnt--;
+		}
+
+		/* only spaces were written */
+		if (isspace(ch)) {
+			*ppos += read;
+			ret = read;
+			goto out;
+		}
+
+		biter->idx = 0;
+	}
+
+	/* read the non-space input */
+	while (cnt && !isspace(ch)) {
+		if (biter->idx < biter->size)
+			biter->buffer[biter->idx++] = ch;
+		else {
+			ret = -EINVAL;
+			goto out;
+		}
+		ret = get_user(ch, ubuf++);
+		if (ret)
+			goto out;
+		read++;
+		cnt--;
+	}
+
+	/* We either got finished input or we have to wait for another call. */
+	if (isspace(ch)) {
+		biter->buffer[biter->idx] = 0;
+		biter->cont = 0;
+	} else {
+		biter->cont = 1;
+		biter->buffer[biter->idx++] = ch;
+	}
+
+	*ppos += read;
+	ret = read;
+
+out:
+	return ret;
+}
+
 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
 {
 	int len;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index d881015..d4e38e8 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -652,6 +652,54 @@ static inline int ftrace_trace_task(struct task_struct *task)
 #endif
 
 /*
+ * struct trace_biter - servers for reading the user input separated by spaces
+ * @cont: set if the input is not complete - no final space char was found
+ * @buffer: holds the parsed user input
+ * @idx: user input lenght
+ * @size: buffer size
+ */
+struct trace_biter {
+	bool		cont;
+	char		*buffer;
+	unsigned	idx;
+	unsigned	size;
+};
+
+#define TRACE_BITER_LOADED(biter) (biter->idx)
+#define TRACE_BITER_CONT(biter)   (biter->cont)
+#define TRACE_BITER_CLEAR(biter) \
+do { \
+	biter->cont = false; \
+	biter->idx = 0; \
+} while(0)
+
+/*
+ * trace_biter_alloc - allocates the buffer for trace buffer iterator
+ */
+static inline int trace_biter_alloc(struct trace_biter *biter, int size)
+{
+	memset(biter, 0, sizeof(*biter));
+
+	biter->buffer = kmalloc(size, GFP_KERNEL);
+	if (!biter->buffer)
+		return 1;
+
+	biter->size = size;
+	return 0;
+}
+
+/*
+ * trace_biter_free - frees the buffer for trace buffer iterator
+ */
+static inline void trace_biter_free(struct trace_biter *biter)
+{
+	kfree(biter->buffer);
+}
+
+extern int trace_get_user(struct trace_biter *biter, const char __user *ubuf,
+	size_t cnt, loff_t *ppos);
+
+/*
  * trace_iterator_flags is an enumeration that defines bit
  * positions into trace_flags that controls the output.
  *
-- 
1.6.2.5

[PATCHv2 2/3] tracing - buf iterator support for set_event

[jolsa]

Updated 'set_event' write method to use the 'trace_get_user' function.

wbr,
jirka

Signed-off-by: Jiri Olsa <jolsa@redhat.com>

---
 kernel/trace/trace_events.c |   58 +++++++++---------------------------------
 1 files changed, 13 insertions(+), 45 deletions(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index d33bcde..7e5703c 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -230,11 +230,9 @@ static ssize_t
 ftrace_event_write(struct file *file, const char __user *ubuf,
 		   size_t cnt, loff_t *ppos)
 {
+	struct trace_biter biter;
 	size_t read = 0;
-	int i, set = 1;
 	ssize_t ret;
-	char *buf;
-	char ch;
 
 	if (!cnt || cnt < 0)
 		return 0;
@@ -243,60 +241,30 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
 	if (ret < 0)
 		return ret;
 
-	ret = get_user(ch, ubuf++);
-	if (ret)
-		return ret;
-	read++;
-	cnt--;
-
-	/* skip white space */
-	while (cnt && isspace(ch)) {
-		ret = get_user(ch, ubuf++);
-		if (ret)
-			return ret;
-		read++;
-		cnt--;
-	}
-
-	/* Only white space found? */
-	if (isspace(ch)) {
-		file->f_pos += read;
-		ret = read;
-		return ret;
-	}
-
-	buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
-	if (!buf)
+	if (trace_biter_alloc(&biter, EVENT_BUF_SIZE + 1))
 		return -ENOMEM;
 
-	if (cnt > EVENT_BUF_SIZE)
-		cnt = EVENT_BUF_SIZE;
+	read = trace_get_user(&biter, ubuf, cnt, ppos);
+
+	if (TRACE_BITER_LOADED((&biter))) {
+		char *buf = biter.buffer;
+		int set = 1;
 
-	i = 0;
-	while (cnt && !isspace(ch)) {
-		if (!i && ch == '!')
+		if (*buf == '!') {
 			set = 0;
-		else
-			buf[i++] = ch;
+			buf++;
+		}
+		biter.buffer[biter.idx] = 0;
 
-		ret = get_user(ch, ubuf++);
+		ret = ftrace_set_clr_event(buf, set);
 		if (ret)
 			goto out_free;
-		read++;
-		cnt--;
 	}
-	buf[i] = 0;
-
-	file->f_pos += read;
-
-	ret = ftrace_set_clr_event(buf, set);
-	if (ret)
-		goto out_free;
 
 	ret = read;
 
  out_free:
-	kfree(buf);
+	trace_biter_free(&biter);
 
 	return ret;
 }
-- 
1.6.2.5

[PATCHv2 3/3] tracing - buf iterator support for set_graph_function set_ftrace_filter set_ftrace_notrace

[jolsa]

Updated 'set_graph_function', 'set_ftrace_filter', 'set_ftrace_notrace' write methods
to use the 'trace_get_user' function.

Removed FTRACE_ITER_CONT flag, since it's not needed after this change.

Fixed minor in set_graph_function display - g_show function.

wbr,
jirka

Signed-off-by: Jiri Olsa <jolsa@redhat.com>

---
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 8c804e2..04bffba 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1323,11 +1323,10 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 
 enum {
 	FTRACE_ITER_FILTER	= (1 << 0),
-	FTRACE_ITER_CONT	= (1 << 1),
-	FTRACE_ITER_NOTRACE	= (1 << 2),
-	FTRACE_ITER_FAILURES	= (1 << 3),
-	FTRACE_ITER_PRINTALL	= (1 << 4),
-	FTRACE_ITER_HASH	= (1 << 5),
+	FTRACE_ITER_NOTRACE	= (1 << 1),
+	FTRACE_ITER_FAILURES	= (1 << 2),
+	FTRACE_ITER_PRINTALL	= (1 << 3),
+	FTRACE_ITER_HASH	= (1 << 4),
 };
 
 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
@@ -1337,8 +1336,7 @@ struct ftrace_iterator {
 	int			hidx;
 	int			idx;
 	unsigned		flags;
-	unsigned char		buffer[FTRACE_BUFF_MAX+1];
-	unsigned		buffer_idx;
+	struct trace_biter	biter;
 };
 
 static void *
@@ -1604,6 +1602,11 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 	if (!iter)
 		return -ENOMEM;
 
+	if (trace_biter_alloc(&iter->biter, FTRACE_BUFF_MAX)) {
+		kfree(iter);
+		return -ENOMEM;
+	}
+
 	mutex_lock(&ftrace_regex_lock);
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC))
@@ -2196,9 +2199,8 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 		   size_t cnt, loff_t *ppos, int enable)
 {
 	struct ftrace_iterator *iter;
-	char ch;
-	size_t read = 0;
-	ssize_t ret;
+	struct trace_biter *biter;
+	ssize_t ret, read;
 
 	if (!cnt || cnt < 0)
 		return 0;
@@ -2211,72 +2213,23 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 	} else
 		iter = file->private_data;
 
-	if (!*ppos) {
-		iter->flags &= ~FTRACE_ITER_CONT;
-		iter->buffer_idx = 0;
-	}
-
-	ret = get_user(ch, ubuf++);
-	if (ret)
-		goto out;
-	read++;
-	cnt--;
+	biter = &iter->biter;
+	read = trace_get_user(biter, ubuf, cnt, ppos);
 
-	/*
-	 * If the parser haven't finished with the last write,
-	 * continue reading the user input without skipping spaces.
-	 */
-	if (!(iter->flags & FTRACE_ITER_CONT)) {
-		/* skip white space */
-		while (cnt && isspace(ch)) {
-			ret = get_user(ch, ubuf++);
-			if (ret)
-				goto out;
-			read++;
-			cnt--;
-		}
-
-		/* only spaces were written */
-		if (isspace(ch)) {
-			*ppos += read;
-			ret = read;
-			goto out;
-		}
-
-		iter->buffer_idx = 0;
-	}
-
-	while (cnt && !isspace(ch)) {
-		if (iter->buffer_idx < FTRACE_BUFF_MAX)
-			iter->buffer[iter->buffer_idx++] = ch;
-		else {
-			ret = -EINVAL;
-			goto out;
-		}
-		ret = get_user(ch, ubuf++);
+	if (TRACE_BITER_LOADED(biter) &&
+	    !TRACE_BITER_CONT(biter)) {
+		ret = ftrace_process_regex(biter->buffer,
+					   biter->idx, enable);
 		if (ret)
 			goto out;
-		read++;
-		cnt--;
-	}
 
-	if (isspace(ch)) {
-		iter->buffer[iter->buffer_idx] = 0;
-		ret = ftrace_process_regex(iter->buffer,
-					   iter->buffer_idx, enable);
-		if (ret)
-			goto out;
-		iter->buffer_idx = 0;
-	} else {
-		iter->flags |= FTRACE_ITER_CONT;
-		iter->buffer[iter->buffer_idx++] = ch;
+		TRACE_BITER_CLEAR(biter);
 	}
 
-	*ppos += read;
 	ret = read;
- out:
-	mutex_unlock(&ftrace_regex_lock);
 
+	mutex_unlock(&ftrace_regex_lock);
+out:
 	return ret;
 }
 
@@ -2381,6 +2334,7 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable)
 {
 	struct seq_file *m = (struct seq_file *)file->private_data;
 	struct ftrace_iterator *iter;
+	struct trace_biter *biter;
 
 	mutex_lock(&ftrace_regex_lock);
 	if (file->f_mode & FMODE_READ) {
@@ -2390,9 +2344,10 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable)
 	} else
 		iter = file->private_data;
 
-	if (iter->buffer_idx) {
-		iter->buffer[iter->buffer_idx] = 0;
-		ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
+	biter = &iter->biter;
+	if (TRACE_BITER_LOADED(biter)) {
+		biter->buffer[biter->idx] = 0;
+		ftrace_match_records(biter->buffer, biter->idx, enable);
 	}
 
 	mutex_lock(&ftrace_lock);
@@ -2400,7 +2355,9 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable)
 		ftrace_run_update_code(FTRACE_ENABLE_CALLS);
 	mutex_unlock(&ftrace_lock);
 
+	trace_biter_free(biter);
 	kfree(iter);
+
 	mutex_unlock(&ftrace_regex_lock);
 	return 0;
 }
@@ -2499,7 +2456,7 @@ static int g_show(struct seq_file *m, void *v)
 		return 0;
 	}
 
-	seq_printf(m, "%pf\n", v);
+	seq_printf(m, "%p\n", (void*) *ptr);
 
 	return 0;
 }
@@ -2602,12 +2559,10 @@ static ssize_t
 ftrace_graph_write(struct file *file, const char __user *ubuf,
 		   size_t cnt, loff_t *ppos)
 {
-	unsigned char buffer[FTRACE_BUFF_MAX+1];
+	struct trace_biter biter;
 	unsigned long *array;
 	size_t read = 0;
 	ssize_t ret;
-	int index = 0;
-	char ch;
 
 	if (!cnt || cnt < 0)
 		return 0;
@@ -2625,51 +2580,27 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
 	} else
 		array = file->private_data;
 
-	ret = get_user(ch, ubuf++);
-	if (ret)
+	if (trace_biter_alloc(&biter, FTRACE_BUFF_MAX)) {
+		ret = -ENOMEM;
 		goto out;
-	read++;
-	cnt--;
-
-	/* skip white space */
-	while (cnt && isspace(ch)) {
-		ret = get_user(ch, ubuf++);
-		if (ret)
-			goto out;
-		read++;
-		cnt--;
 	}
 
-	if (isspace(ch)) {
-		*ppos += read;
-		ret = read;
-		goto out;
-	}
+	read = trace_get_user(&biter, ubuf, cnt, ppos);
+
+	if (TRACE_BITER_LOADED((&biter))) {
+		biter.buffer[biter.idx] = 0;
+
+		/* we allow only one expression at a time */
+		ret = ftrace_set_func(array, &ftrace_graph_count,
+					biter.buffer);
 
-	while (cnt && !isspace(ch)) {
-		if (index < FTRACE_BUFF_MAX)
-			buffer[index++] = ch;
-		else {
-			ret = -EINVAL;
-			goto out;
-		}
-		ret = get_user(ch, ubuf++);
 		if (ret)
 			goto out;
-		read++;
-		cnt--;
 	}
-	buffer[index] = 0;
-
-	/* we allow only one expression at a time */
-	ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
-	if (ret)
-		goto out;
-
-	file->f_pos += read;
 
 	ret = read;
  out:
+	trace_biter_free(&biter);
 	mutex_unlock(&graph_lock);
 
 	return ret;

Re: [PATCHv2 0/3] tracing - adding common method for reading/parsing user input

[Daniel Walker]

On Sat, 2009-09-05 at 03:12 +0200, jolsa@redhat.com wrote:
> As 3 different places for 4 user input files were using the same way
> of reading and parsing user's input, I made one common routine to be
> used. 
> 

Patches 1 and 3 have a couple of minor checkpatch errors.. 

Daniel

Re: [PATCHv2 0/3] tracing - adding common method for reading/parsing user input

[Jiri Olsa]

On Fri, Sep 04, 2009 at 07:41:26PM -0700, Daniel Walker wrote:
> On Sat, 2009-09-05 at 03:12 +0200, jolsa@redhat.com wrote:
> > As 3 different places for 4 user input files were using the same way
> > of reading and parsing user's input, I made one common routine to be
> > used. 
> > 
> 
> Patches 1 and 3 have a couple of minor checkpatch errors.. 
> 
> Daniel
>

thanks, let me send out those changes later after I get other comments

wbr,
jirka

Re: [PATCHv2 0/3] tracing - adding common method for reading/parsing user input

[Steven Rostedt]

On Sat, 2009-09-05 at 08:40 +0200, Jiri Olsa wrote:
> On Fri, Sep 04, 2009 at 07:41:26PM -0700, Daniel Walker wrote:
> > On Sat, 2009-09-05 at 03:12 +0200, jolsa@redhat.com wrote:
> > > As 3 different places for 4 user input files were using the same way
> > > of reading and parsing user's input, I made one common routine to be
> > > used. 
> > > 
> > 
> > Patches 1 and 3 have a couple of minor checkpatch errors.. 
> > 
> > Daniel
> >
> 
> thanks, let me send out those changes later after I get other comments

I wont be able to look at these until next week.

-- Steve

Re: [PATCHv2 1/3] tracing - buf iterator definition, parsing function

[Steven Rostedt]

On Sat, 2009-09-05 at 03:12 +0200, jolsa@redhat.com wrote:
> Defined 'trace_biter' structure to carry the properties of the input,
> through the multiple writes.
> 
> The 'trace_get_user' reads the user incput string separated by space

incput?

> (matched by isspace(ch). For each string found the 'struct trace_biter' 
> iterator is updated, and the function returns.
> 
> wbr,
> jirka
> 
> Signed-off-by: Jiri Olsa <jolsa@redhat.com>
> 
> ---
>  kernel/trace/trace.c |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  kernel/trace/trace.h |   48 +++++++++++++++++++++++++++++
>  2 files changed, 131 insertions(+), 0 deletions(-)
> 
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index af15008..8cf8f99 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -335,6 +335,89 @@ static struct {
>  
>  int trace_clock_id;
>  
> +/*
> + * trace_get_user - reads the user incput string separated by  space

incput again?

> + * (matched by isspace(ch))
> + *
> + * For each string found the 'struct trace_biter' iterator is updated,
> + * and the function returns.
> + *
> + * Returns number of bytes read.
> + *
> + * see kernel/trace/trace.h for 'struct trace_biter' details.
> + */
> +int trace_get_user(struct trace_biter *biter, const char __user *ubuf,
> +	size_t cnt, loff_t *ppos)
> +{
> +	char ch;
> +	size_t read = 0;
> +	ssize_t ret;
> +
> +	if (!*ppos)
> +		TRACE_BITER_CLEAR(biter);
> +
> +	ret = get_user(ch, ubuf++);
> +	if (ret)
> +		goto out;
> +
> +	read++;
> +	cnt--;
> +
> +	/*
> +	 * If the parser haven't finished with the last write,
> +	 * continue reading the user input without skipping spaces.
> +	 */
> +	if (!biter->cont) {
> +		/* skip white space */
> +		while (cnt && isspace(ch)) {
> +			ret = get_user(ch, ubuf++);
> +			if (ret)
> +				goto out;
> +			read++;
> +			cnt--;
> +		}
> +
> +		/* only spaces were written */
> +		if (isspace(ch)) {
> +			*ppos += read;
> +			ret = read;
> +			goto out;
> +		}
> +
> +		biter->idx = 0;
> +	}
> +
> +	/* read the non-space input */
> +	while (cnt && !isspace(ch)) {
> +		if (biter->idx < biter->size)
> +			biter->buffer[biter->idx++] = ch;
> +		else {
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +		ret = get_user(ch, ubuf++);
> +		if (ret)
> +			goto out;
> +		read++;
> +		cnt--;
> +	}
> +
> +	/* We either got finished input or we have to wait for another call. */
> +	if (isspace(ch)) {
> +		biter->buffer[biter->idx] = 0;
> +		biter->cont = 0;
> +	} else {
> +		biter->cont = 1;
> +		biter->buffer[biter->idx++] = ch;
> +	}
> +
> +	*ppos += read;
> +	ret = read;
> +
> +out:
> +	return ret;
> +}
> +
>  ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
>  {
>  	int len;
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index d881015..d4e38e8 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -652,6 +652,54 @@ static inline int ftrace_trace_task(struct task_struct *task)
>  #endif
>  
>  /*
> + * struct trace_biter - servers for reading the user input separated by spaces
> + * @cont: set if the input is not complete - no final space char was found
> + * @buffer: holds the parsed user input
> + * @idx: user input lenght

 length

> + * @size: buffer size
> + */
> +struct trace_biter {
> +	bool		cont;
> +	char		*buffer;
> +	unsigned	idx;
> +	unsigned	size;
> +};
> +
> +#define TRACE_BITER_LOADED(biter) (biter->idx)
> +#define TRACE_BITER_CONT(biter)   (biter->cont)
> +#define TRACE_BITER_CLEAR(biter) \
> +do { \
> +	biter->cont = false; \
> +	biter->idx = 0; \
> +} while(0)
> +
> +/*
> + * trace_biter_alloc - allocates the buffer for trace buffer iterator
> + */
> +static inline int trace_biter_alloc(struct trace_biter *biter, int size)
> +{
> +	memset(biter, 0, sizeof(*biter));
> +
> +	biter->buffer = kmalloc(size, GFP_KERNEL);
> +	if (!biter->buffer)
> +		return 1;
> +
> +	biter->size = size;
> +	return 0;
> +}

I don't see any reason that trace_biter_alloc is as static inline in a
header file. It should be a normal function in trace.c

> +
> +/*
> + * trace_biter_free - frees the buffer for trace buffer iterator
> + */
> +static inline void trace_biter_free(struct trace_biter *biter)
> +{
> +	kfree(biter->buffer);
> +}

trace_biter_free too.

But I also hate the name "biter", looks too much like "bitter". How
about something like "trace_parser", or "trace_string_reader"?

-- Steve

> +
> +extern int trace_get_user(struct trace_biter *biter, const char __user *ubuf,
> +	size_t cnt, loff_t *ppos);
> +
> +/*
>   * trace_iterator_flags is an enumeration that defines bit
>   * positions into trace_flags that controls the output.
>   *

Re: [PATCHv2 0/3] tracing - adding common method for reading/parsing user input

[Steven Rostedt]

On Sat, 2009-09-05 at 03:12 +0200, jolsa@redhat.com wrote:
> As 3 different places for 4 user input files were using the same way
> of reading and parsing user's input, I made one common routine to be
> used. 
> 
> The mentioned files are:
> 	set_graph_function
> 	set_event
> 	set_ftrace_filter
> 	set_ftrace_notrace
> 
> wbr,
> jirka
> 
> Signed-off-by: Jiri Olsa <jolsa@redhat.com>

Looking back, this is pretty much exactly what I did back in February:

  http://lkml.org/lkml/2009/2/25/385

The difference is that I wanted this to be a generic feature for things
outside of tracing to use. I may just take my old patch and put the code
in trace.c like you did.

Thanks,

-- Steve

Re: [PATCHv2 0/3] tracing - adding common method for reading/parsing user input

[Jiri Olsa]

On Tue, Sep 08, 2009 at 10:01:39AM -0400, Steven Rostedt wrote:
> On Sat, 2009-09-05 at 03:12 +0200, jolsa@redhat.com wrote:
> > As 3 different places for 4 user input files were using the same way
> > of reading and parsing user's input, I made one common routine to be
> > used. 
> > 
> > The mentioned files are:
> > 	set_graph_function
> > 	set_event
> > 	set_ftrace_filter
> > 	set_ftrace_notrace
> > 
> > wbr,
> > jirka
> > 
> > Signed-off-by: Jiri Olsa <jolsa@redhat.com>
> 
> Looking back, this is pretty much exactly what I did back in February:
> 
>   http://lkml.org/lkml/2009/2/25/385
> 
> The difference is that I wanted this to be a generic feature for things
> outside of tracing to use. I may just take my old patch and put the code
> in trace.c like you did.
> 
> Thanks,
> 
> -- Steve
> 
> 

ok, so are you going to take your patch, or should I do the changes you
proposed and send it out again?

wbr,
jirka

Re: [PATCHv2 0/3] tracing - adding common method for reading/parsing user input

[Steven Rostedt]

On Tue, 2009-09-08 at 16:37 +0200, Jiri Olsa wrote:
> On Tue, Sep 08, 2009 at 10:01:39AM -0400, Steven Rostedt wrote:

> 
> ok, so are you going to take your patch, or should I do the changes you
> proposed and send it out again?

Yeah, I may forward port my patch. But I may take some things from your
patch and apply them too. I'll put your name in the change log too ;-)

Thanks,

-- Steve

Re: [PATCHv2 0/3] tracing - adding common method for reading/parsing user input

[Jiri Olsa]

On Tue, Sep 08, 2009 at 10:44:30AM -0400, Steven Rostedt wrote:
> On Tue, 2009-09-08 at 16:37 +0200, Jiri Olsa wrote:
> > On Tue, Sep 08, 2009 at 10:01:39AM -0400, Steven Rostedt wrote:
> 
> > 
> > ok, so are you going to take your patch, or should I do the changes you
> > proposed and send it out again?
> 
> Yeah, I may forward port my patch. But I may take some things from your
> patch and apply them too. I'll put your name in the change log too ;-)
> 
> Thanks,
> 
> -- Steve
> 
> 
ok, cool :)

thanks,
jirka

Re: [PATCHv2 1/3] tracing - buf iterator definition, parsing function

[Steven Rostedt]

Ah, after working with my old patches, I think I like yours better ;-)

But I still have some issues. I'll comment on them, and if you can send
out a v3 with the updates, I'll apply them.

On Sat, 2009-09-05 at 03:12 +0200, jolsa@redhat.com wrote:
> Defined 'trace_biter' structure to carry the properties of the input,
> through the multiple writes.
> 
> The 'trace_get_user' reads the user incput string separated by space
> (matched by isspace(ch). For each string found the 'struct trace_biter' 
> iterator is updated, and the function returns.
> 
> wbr,
> jirka
> 
> Signed-off-by: Jiri Olsa <jolsa@redhat.com>
> 
> ---
>  kernel/trace/trace.c |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  kernel/trace/trace.h |   48 +++++++++++++++++++++++++++++
>  2 files changed, 131 insertions(+), 0 deletions(-)
> 
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index af15008..8cf8f99 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -335,6 +335,89 @@ static struct {
>  
>  int trace_clock_id;
>  
> +/*
> + * trace_get_user - reads the user incput string separated by  space

typo - incput

> + * (matched by isspace(ch))
> + *
> + * For each string found the 'struct trace_biter' iterator is updated,

Call it trace_parser, I hate the sound of trace_biter (I keep
pronouncing it as bitter).

> + * and the function returns.
> + *
> + * Returns number of bytes read.
> + *
> + * see kernel/trace/trace.h for 'struct trace_biter' details.
> + */
> +int trace_get_user(struct trace_biter *biter, const char __user *ubuf,

s/biter/parser/g

> +	size_t cnt, loff_t *ppos)
> +{
> +	char ch;
> +	size_t read = 0;
> +	ssize_t ret;
> +
> +	if (!*ppos)
> +		TRACE_BITER_CLEAR(biter);

Don't do this with macros (explained below)

> +
> +	ret = get_user(ch, ubuf++);
> +	if (ret)
> +		goto out;
> +
> +	read++;
> +	cnt--;
> +
> +	/*
> +	 * If the parser haven't finished with the last write,

grammar nit - "If the parser is not finished ..."

> +	 * continue reading the user input without skipping spaces.
> +	 */
> +	if (!biter->cont) {
> +		/* skip white space */
> +		while (cnt && isspace(ch)) {
> +			ret = get_user(ch, ubuf++);
> +			if (ret)
> +				goto out;
> +			read++;
> +			cnt--;
> +		}
> +
> +		/* only spaces were written */
> +		if (isspace(ch)) {
> +			*ppos += read;
> +			ret = read;
> +			goto out;
> +		}
> +
> +		biter->idx = 0;
> +	}
> +
> +	/* read the non-space input */
> +	while (cnt && !isspace(ch)) {
> +		if (biter->idx < biter->size)
> +			biter->buffer[biter->idx++] = ch;
> +		else {
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +		ret = get_user(ch, ubuf++);
> +		if (ret)
> +			goto out;
> +		read++;
> +		cnt--;
> +	}
> +
> +	/* We either got finished input or we have to wait for another call. */
> +	if (isspace(ch)) {
> +		biter->buffer[biter->idx] = 0;
> +		biter->cont = 0;
> +	} else {
> +		biter->cont = 1;
> +		biter->buffer[biter->idx++] = ch;
> +	}
> +
> +	*ppos += read;
> +	ret = read;
> +
> +out:
> +	return ret;
> +}
> +
>  ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
>  {
>  	int len;
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index d881015..d4e38e8 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -652,6 +652,54 @@ static inline int ftrace_trace_task(struct task_struct *task)
>  #endif
>  
>  /*
> + * struct trace_biter - servers for reading the user input separated by spaces

Again, rename to trace_parser.

> + * @cont: set if the input is not complete - no final space char was found
> + * @buffer: holds the parsed user input
> + * @idx: user input lenght
> + * @size: buffer size
> + */
> +struct trace_biter {
> +	bool		cont;
> +	char		*buffer;
> +	unsigned	idx;
> +	unsigned	size;
> +};
> +
> +#define TRACE_BITER_LOADED(biter) (biter->idx)
> +#define TRACE_BITER_CONT(biter)   (biter->cont)
> +#define TRACE_BITER_CLEAR(biter) \
> +do { \
> +	biter->cont = false; \
> +	biter->idx = 0; \
> +} while(0)

Ug, just use parser->idx directly. No need for macros. Or if you want to
encapsulate this, then use static inline functions. Avoid MACROS, they
just make the code ugly.

> +
> +/*
> + * trace_biter_alloc - allocates the buffer for trace buffer iterator
> + */
> +static inline int trace_biter_alloc(struct trace_biter *biter, int size)

Using alloc as the name here is confusing because you are passing in a
struct trace_parser already, so you are not allocating one. Rename it to
trace_parser_get_init().

> +{
> +	memset(biter, 0, sizeof(*biter));
> +
> +	biter->buffer = kmalloc(size, GFP_KERNEL);
> +	if (!biter->buffer)
> +		return 1;
> +
> +	biter->size = size;
> +	return 0;
> +}
> +
> +/*
> + * trace_biter_free - frees the buffer for trace buffer iterator
> + */
> +static inline void trace_biter_free(struct trace_biter *biter)

And again, you are not freeing the trace_parser. Lets rename this to
trace_parser_put(). This way we have a get/put pair that developers can
relate to. Maybe another name pair may be more appropriate, but when you
call something x_alloc/x_free, it refers to allocating and freeing x,
not a part of x.

-- Steve


> +{
> +	kfree(biter->buffer);
> +}
> +
> +extern int trace_get_user(struct trace_biter *biter, const char __user *ubuf,
> +	size_t cnt, loff_t *ppos);
> +
> +/*
>   * trace_iterator_flags is an enumeration that defines bit
>   * positions into trace_flags that controls the output.
>   *

Re: [PATCHv2 2/3] tracing - buf iterator support for set_event

[Steven Rostedt]

On Sat, 2009-09-05 at 03:13 +0200, jolsa@redhat.com wrote:
> Updated 'set_event' write method to use the 'trace_get_user' function.
> 
> wbr,
> jirka
> 
> Signed-off-by: Jiri Olsa <jolsa@redhat.com>
> 
> ---
>  kernel/trace/trace_events.c |   58 +++++++++---------------------------------
>  1 files changed, 13 insertions(+), 45 deletions(-)
> 
> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> index d33bcde..7e5703c 100644
> --- a/kernel/trace/trace_events.c
> +++ b/kernel/trace/trace_events.c
> @@ -230,11 +230,9 @@ static ssize_t
>  ftrace_event_write(struct file *file, const char __user *ubuf,
>  		   size_t cnt, loff_t *ppos)
>  {
> +	struct trace_biter biter;

s/biter/parser/g

>  	size_t read = 0;
> -	int i, set = 1;
>  	ssize_t ret;
> -	char *buf;
> -	char ch;
>  
>  	if (!cnt || cnt < 0)
>  		return 0;
> @@ -243,60 +241,30 @@ ftrace_event_write(struct file *file, const char __user *ubuf,
>  	if (ret < 0)
>  		return ret;
>  
> -	ret = get_user(ch, ubuf++);
> -	if (ret)
> -		return ret;
> -	read++;
> -	cnt--;
> -
> -	/* skip white space */
> -	while (cnt && isspace(ch)) {
> -		ret = get_user(ch, ubuf++);
> -		if (ret)
> -			return ret;
> -		read++;
> -		cnt--;
> -	}
> -
> -	/* Only white space found? */
> -	if (isspace(ch)) {
> -		file->f_pos += read;
> -		ret = read;
> -		return ret;
> -	}
> -
> -	buf = kmalloc(EVENT_BUF_SIZE+1, GFP_KERNEL);
> -	if (!buf)
> +	if (trace_biter_alloc(&biter, EVENT_BUF_SIZE + 1))
>  		return -ENOMEM;
>  
> -	if (cnt > EVENT_BUF_SIZE)
> -		cnt = EVENT_BUF_SIZE;
> +	read = trace_get_user(&biter, ubuf, cnt, ppos);
> +
> +	if (TRACE_BITER_LOADED((&biter))) {
> +		char *buf = biter.buffer;

If you have encapsulated the access to parser with trace_parser_loaded,
might as well do the same for getting the buffer:

static inline char *trace_parser_buffer(struct trace_parser *parser)
{
	return parser->buffer;
}


> +		int set = 1;
>  
> -	i = 0;
> -	while (cnt && !isspace(ch)) {
> -		if (!i && ch == '!')
> +		if (*buf == '!') {
>  			set = 0;
> -		else
> -			buf[i++] = ch;
> +			buf++;

I had a funny trick in my patches to instead of incrementing buf here, I
passed in below a:

	ftrace_set_clr_event(buf + !!set, set);

But whatever ;-)

> +		}
> +		biter.buffer[biter.idx] = 0;

here you are accessing both the buffer and idx directly. Might as well
do it everywhere like this and don't use the helper functions.

-- Steve

>  
> -		ret = get_user(ch, ubuf++);
> +		ret = ftrace_set_clr_event(buf, set);
>  		if (ret)
>  			goto out_free;
> -		read++;
> -		cnt--;
>  	}
> -	buf[i] = 0;
> -
> -	file->f_pos += read;
> -
> -	ret = ftrace_set_clr_event(buf, set);
> -	if (ret)
> -		goto out_free;
>  
>  	ret = read;
>  
>   out_free:
> -	kfree(buf);
> +	trace_biter_free(&biter);
>  
>  	return ret;
>  }

Re: [PATCHv2 3/3] tracing - buf iterator support for set_graph_function set_ftrace_filter set_ftrace_notrace

[Steven Rostedt]

On Sat, 2009-09-05 at 03:13 +0200, jolsa@redhat.com wrote:
> Updated 'set_graph_function', 'set_ftrace_filter', 'set_ftrace_notrace' write methods
> to use the 'trace_get_user' function.
> 
> Removed FTRACE_ITER_CONT flag, since it's not needed after this change.
> 
> Fixed minor in set_graph_function display - g_show function.
> 

This patch seems fine as long as it gets updated with the same comments
of the other patches.

-- Steve

> wbr,
> jirka
> 
> Signed-off-by: Jiri Olsa <jolsa@redhat.com>
> 
> ---
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 8c804e2..04bffba 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -1323,11 +1323,10 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
>  
>  enum {
>  	FTRACE_ITER_FILTER	= (1 << 0),
> -	FTRACE_ITER_CONT	= (1 << 1),
> -	FTRACE_ITER_NOTRACE	= (1 << 2),
> -	FTRACE_ITER_FAILURES	= (1 << 3),
> -	FTRACE_ITER_PRINTALL	= (1 << 4),
> -	FTRACE_ITER_HASH	= (1 << 5),
> +	FTRACE_ITER_NOTRACE	= (1 << 1),
> +	FTRACE_ITER_FAILURES	= (1 << 2),
> +	FTRACE_ITER_PRINTALL	= (1 << 3),
> +	FTRACE_ITER_HASH	= (1 << 4),
>  };
>  
>  #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
> @@ -1337,8 +1336,7 @@ struct ftrace_iterator {
>  	int			hidx;
>  	int			idx;
>  	unsigned		flags;
> -	unsigned char		buffer[FTRACE_BUFF_MAX+1];
> -	unsigned		buffer_idx;
> +	struct trace_biter	biter;
>  };
>  
>  static void *
> @@ -1604,6 +1602,11 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
>  	if (!iter)
>  		return -ENOMEM;
>  
> +	if (trace_biter_alloc(&iter->biter, FTRACE_BUFF_MAX)) {
> +		kfree(iter);
> +		return -ENOMEM;
> +	}
> +
>  	mutex_lock(&ftrace_regex_lock);
>  	if ((file->f_mode & FMODE_WRITE) &&
>  	    (file->f_flags & O_TRUNC))
> @@ -2196,9 +2199,8 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
>  		   size_t cnt, loff_t *ppos, int enable)
>  {
>  	struct ftrace_iterator *iter;
> -	char ch;
> -	size_t read = 0;
> -	ssize_t ret;
> +	struct trace_biter *biter;
> +	ssize_t ret, read;
>  
>  	if (!cnt || cnt < 0)
>  		return 0;
> @@ -2211,72 +2213,23 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
>  	} else
>  		iter = file->private_data;
>  
> -	if (!*ppos) {
> -		iter->flags &= ~FTRACE_ITER_CONT;
> -		iter->buffer_idx = 0;
> -	}
> -
> -	ret = get_user(ch, ubuf++);
> -	if (ret)
> -		goto out;
> -	read++;
> -	cnt--;
> +	biter = &iter->biter;
> +	read = trace_get_user(biter, ubuf, cnt, ppos);
>  
> -	/*
> -	 * If the parser haven't finished with the last write,
> -	 * continue reading the user input without skipping spaces.
> -	 */
> -	if (!(iter->flags & FTRACE_ITER_CONT)) {
> -		/* skip white space */
> -		while (cnt && isspace(ch)) {
> -			ret = get_user(ch, ubuf++);
> -			if (ret)
> -				goto out;
> -			read++;
> -			cnt--;
> -		}
> -
> -		/* only spaces were written */
> -		if (isspace(ch)) {
> -			*ppos += read;
> -			ret = read;
> -			goto out;
> -		}
> -
> -		iter->buffer_idx = 0;
> -	}
> -
> -	while (cnt && !isspace(ch)) {
> -		if (iter->buffer_idx < FTRACE_BUFF_MAX)
> -			iter->buffer[iter->buffer_idx++] = ch;
> -		else {
> -			ret = -EINVAL;
> -			goto out;
> -		}
> -		ret = get_user(ch, ubuf++);
> +	if (TRACE_BITER_LOADED(biter) &&
> +	    !TRACE_BITER_CONT(biter)) {
> +		ret = ftrace_process_regex(biter->buffer,
> +					   biter->idx, enable);
>  		if (ret)
>  			goto out;
> -		read++;
> -		cnt--;
> -	}
>  
> -	if (isspace(ch)) {
> -		iter->buffer[iter->buffer_idx] = 0;
> -		ret = ftrace_process_regex(iter->buffer,
> -					   iter->buffer_idx, enable);
> -		if (ret)
> -			goto out;
> -		iter->buffer_idx = 0;
> -	} else {
> -		iter->flags |= FTRACE_ITER_CONT;
> -		iter->buffer[iter->buffer_idx++] = ch;
> +		TRACE_BITER_CLEAR(biter);
>  	}
>  
> -	*ppos += read;
>  	ret = read;
> - out:
> -	mutex_unlock(&ftrace_regex_lock);
>  
> +	mutex_unlock(&ftrace_regex_lock);
> +out:
>  	return ret;
>  }
>  
> @@ -2381,6 +2334,7 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable)
>  {
>  	struct seq_file *m = (struct seq_file *)file->private_data;
>  	struct ftrace_iterator *iter;
> +	struct trace_biter *biter;
>  
>  	mutex_lock(&ftrace_regex_lock);
>  	if (file->f_mode & FMODE_READ) {
> @@ -2390,9 +2344,10 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable)
>  	} else
>  		iter = file->private_data;
>  
> -	if (iter->buffer_idx) {
> -		iter->buffer[iter->buffer_idx] = 0;
> -		ftrace_match_records(iter->buffer, iter->buffer_idx, enable);
> +	biter = &iter->biter;
> +	if (TRACE_BITER_LOADED(biter)) {
> +		biter->buffer[biter->idx] = 0;
> +		ftrace_match_records(biter->buffer, biter->idx, enable);
>  	}
>  
>  	mutex_lock(&ftrace_lock);
> @@ -2400,7 +2355,9 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable)
>  		ftrace_run_update_code(FTRACE_ENABLE_CALLS);
>  	mutex_unlock(&ftrace_lock);
>  
> +	trace_biter_free(biter);
>  	kfree(iter);
> +
>  	mutex_unlock(&ftrace_regex_lock);
>  	return 0;
>  }
> @@ -2499,7 +2456,7 @@ static int g_show(struct seq_file *m, void *v)
>  		return 0;
>  	}
>  
> -	seq_printf(m, "%pf\n", v);
> +	seq_printf(m, "%p\n", (void*) *ptr);
>  
>  	return 0;
>  }
> @@ -2602,12 +2559,10 @@ static ssize_t
>  ftrace_graph_write(struct file *file, const char __user *ubuf,
>  		   size_t cnt, loff_t *ppos)
>  {
> -	unsigned char buffer[FTRACE_BUFF_MAX+1];
> +	struct trace_biter biter;
>  	unsigned long *array;
>  	size_t read = 0;
>  	ssize_t ret;
> -	int index = 0;
> -	char ch;
>  
>  	if (!cnt || cnt < 0)
>  		return 0;
> @@ -2625,51 +2580,27 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
>  	} else
>  		array = file->private_data;
>  
> -	ret = get_user(ch, ubuf++);
> -	if (ret)
> +	if (trace_biter_alloc(&biter, FTRACE_BUFF_MAX)) {
> +		ret = -ENOMEM;
>  		goto out;
> -	read++;
> -	cnt--;
> -
> -	/* skip white space */
> -	while (cnt && isspace(ch)) {
> -		ret = get_user(ch, ubuf++);
> -		if (ret)
> -			goto out;
> -		read++;
> -		cnt--;
>  	}
>  
> -	if (isspace(ch)) {
> -		*ppos += read;
> -		ret = read;
> -		goto out;
> -	}
> +	read = trace_get_user(&biter, ubuf, cnt, ppos);
> +
> +	if (TRACE_BITER_LOADED((&biter))) {
> +		biter.buffer[biter.idx] = 0;
> +
> +		/* we allow only one expression at a time */
> +		ret = ftrace_set_func(array, &ftrace_graph_count,
> +					biter.buffer);
>  
> -	while (cnt && !isspace(ch)) {
> -		if (index < FTRACE_BUFF_MAX)
> -			buffer[index++] = ch;
> -		else {
> -			ret = -EINVAL;
> -			goto out;
> -		}
> -		ret = get_user(ch, ubuf++);
>  		if (ret)
>  			goto out;
> -		read++;
> -		cnt--;
>  	}
> -	buffer[index] = 0;
> -
> -	/* we allow only one expression at a time */
> -	ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
> -	if (ret)
> -		goto out;
> -
> -	file->f_pos += read;
>  
>  	ret = read;
>   out:
> +	trace_biter_free(&biter);
>  	mutex_unlock(&graph_lock);
>  
>  	return ret;