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Commit 85a2f9b4 authored by Steven Rostedt's avatar Steven Rostedt
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tracing: use pointer error returns for __tracing_open 



Impact: fix compile warning and clean up

When I first wrote __tracing_open, instead of passing the error
code via the ERR_PTR macros, I lazily used a separate parameter
to hold the return for errors.

When Frederic Weisbecker updated that function, he used the Linux
kernel ERR_PTR for the returns. This caused the parameter return
to possibly not be initialized on error. gcc correctly pointed this
out with a warning.

This patch converts the entire function to use the Linux kernel
ERR_PTR macro methods.

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
parent d8e83d26

kernel/trace/trace.c

+24 −22
Original line number Original line Diff line number Diff line
@@ -1684,23 +1684,20 @@ static struct seq_operations tracer_seq_ops = { 
};

};





static struct trace_iterator *

static struct trace_iterator *

__tracing_open(struct inode *inode, struct file *file, int *ret)

__tracing_open(struct inode *inode, struct file *file)

{

{

	long cpu_file = (long) inode->i_private;

	long cpu_file = (long) inode->i_private;

	void *fail_ret = ERR_PTR(-ENOMEM);

	struct trace_iterator *iter;

	struct trace_iterator *iter;

	struct seq_file *m;

	struct seq_file *m;

	int cpu;

	int cpu, ret;





	if (tracing_disabled) {

	if (tracing_disabled)

		*ret = -ENODEV;

		return ERR_PTR(-ENODEV);

		return NULL;

	}





	iter = kzalloc(sizeof(*iter), GFP_KERNEL);

	iter = kzalloc(sizeof(*iter), GFP_KERNEL);

	if (!iter) {

	if (!iter)

		*ret = -ENOMEM;

		return ERR_PTR(-ENOMEM);

		goto out;

	}





	/*

	/*

	 * We make a copy of the current tracer to avoid concurrent

	 * We make a copy of the current tracer to avoid concurrent
@@ -1708,10 +1705,9 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) 
	 */

	 */

	mutex_lock(&trace_types_lock);

	mutex_lock(&trace_types_lock);

	iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);

	iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);

	if (!iter->trace) {

	if (!iter->trace)

		*ret = -ENOMEM;

		goto fail;

		goto fail;

	}



	if (current_trace)

	if (current_trace)

		*iter->trace = *current_trace;

		*iter->trace = *current_trace;
@@ -1750,9 +1746,11 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) 
	}

	}





	/* TODO stop tracer */

	/* TODO stop tracer */

	*ret = seq_open(file, &tracer_seq_ops);

	ret = seq_open(file, &tracer_seq_ops);

	if (*ret)

	if (ret < 0) {

		fail_ret = ERR_PTR(ret);

		goto fail_buffer;

		goto fail_buffer;

	}





	m = file->private_data;

	m = file->private_data;

	m->private = iter;

	m->private = iter;
@@ -1762,7 +1760,6 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) 




	mutex_unlock(&trace_types_lock);

	mutex_unlock(&trace_types_lock);





 out:

	return iter;

	return iter;





 fail_buffer:

 fail_buffer:
@@ -1775,7 +1772,7 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) 
	kfree(iter->trace);

	kfree(iter->trace);

	kfree(iter);

	kfree(iter);





	return ERR_PTR(-ENOMEM);

	return fail_ret;

}

}





int tracing_open_generic(struct inode *inode, struct file *filp)

int tracing_open_generic(struct inode *inode, struct file *filp)
@@ -1815,9 +1812,12 @@ static int tracing_release(struct inode *inode, struct file *file) 




static int tracing_open(struct inode *inode, struct file *file)

static int tracing_open(struct inode *inode, struct file *file)

{

{

	int ret;

	struct trace_iterator *iter;

	int ret = 0;





	__tracing_open(inode, file, &ret);

	iter = __tracing_open(inode, file);

	if (IS_ERR(iter))

		ret = PTR_ERR(iter);





	return ret;

	return ret;

}

}
@@ -1825,11 +1825,13 @@ static int tracing_open(struct inode *inode, struct file *file) 
static int tracing_lt_open(struct inode *inode, struct file *file)

static int tracing_lt_open(struct inode *inode, struct file *file)

{

{

	struct trace_iterator *iter;

	struct trace_iterator *iter;

	int ret;

	int ret = 0;





	iter = __tracing_open(inode, file, &ret);

	iter = __tracing_open(inode, file);





	if (!ret)

	if (IS_ERR(iter))

		ret = PTR_ERR(iter);

	else

		iter->iter_flags |= TRACE_FILE_LAT_FMT;

		iter->iter_flags |= TRACE_FILE_LAT_FMT;





	return ret;

	return ret;