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Commit 098c879e authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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tracing: Add generic tracing_lseek() function 



Trace event triggers added a lseek that uses the ftrace_filter_lseek()
function. Unfortunately, when function tracing is not configured in
that function is not defined and the kernel fails to build.

This is the second time that function was added to a file ops and
it broke the build due to requiring special config dependencies.

Make a generic tracing_lseek() that all the tracing utilities may
use.

Also, modify the old ftrace_filter_lseek() to return 0 instead of
1 on WRONLY. Not sure why it was a 1 as that does not make sense.

This also changes the old tracing_seek() to modify the file pos
pointer on WRONLY as well.

Reported-by: default avatarkbuild test robot <fengguang.wu@intel.com>
Tested-by: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
Acked-by: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent ac38fb85

include/linux/ftrace.h

+0 −2
Original line number Diff line number Diff line
@@ -570,8 +570,6 @@ static inline int 
ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }

#endif /* CONFIG_DYNAMIC_FTRACE */



loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int whence);



/* totally disable ftrace - can not re-enable after this */

void ftrace_kill(void);

kernel/trace/ftrace.c

+6 −19
Original line number Diff line number Diff line
@@ -1082,19 +1082,6 @@ static __init void ftrace_profile_debugfs(struct dentry *d_tracer) 


static struct pid * const ftrace_swapper_pid = &init_struct_pid;



loff_t

ftrace_filter_lseek(struct file *file, loff_t offset, int whence)

{

	loff_t ret;



	if (file->f_mode & FMODE_READ)

		ret = seq_lseek(file, offset, whence);

	else

		file->f_pos = ret = 1;



	return ret;

}



#ifdef CONFIG_DYNAMIC_FTRACE



#ifndef CONFIG_FTRACE_MCOUNT_RECORD
@@ -2739,7 +2726,7 @@ static void ftrace_filter_reset(struct ftrace_hash *hash) 
 * routine, you can use ftrace_filter_write() for the write

 * routine if @flag has FTRACE_ITER_FILTER set, or

 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.

 * ftrace_filter_lseek() should be used as the lseek routine, and

 * tracing_lseek() should be used as the lseek routine, and

 * release must call ftrace_regex_release().

 */

int
@@ -3767,7 +3754,7 @@ static const struct file_operations ftrace_filter_fops = { 
	.open = ftrace_filter_open,

	.read = seq_read,

	.write = ftrace_filter_write,

	.llseek = ftrace_filter_lseek,

	.llseek = tracing_lseek,

	.release = ftrace_regex_release,

};
@@ -3775,7 +3762,7 @@ static const struct file_operations ftrace_notrace_fops = { 
	.open = ftrace_notrace_open,

	.read = seq_read,

	.write = ftrace_notrace_write,

	.llseek = ftrace_filter_lseek,

	.llseek = tracing_lseek,

	.release = ftrace_regex_release,

};
@@ -4038,7 +4025,7 @@ static const struct file_operations ftrace_graph_fops = { 
	.open		= ftrace_graph_open,

	.read		= seq_read,

	.write		= ftrace_graph_write,

	.llseek		= ftrace_filter_lseek,

	.llseek		= tracing_lseek,

	.release	= ftrace_graph_release,

};
@@ -4046,7 +4033,7 @@ static const struct file_operations ftrace_graph_notrace_fops = { 
	.open		= ftrace_graph_notrace_open,

	.read		= seq_read,

	.write		= ftrace_graph_write,

	.llseek		= ftrace_filter_lseek,

	.llseek		= tracing_lseek,

	.release	= ftrace_graph_release,

};

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
@@ -4719,7 +4706,7 @@ static const struct file_operations ftrace_pid_fops = { 
	.open		= ftrace_pid_open,

	.write		= ftrace_pid_write,

	.read		= seq_read,

	.llseek		= ftrace_filter_lseek,

	.llseek		= tracing_lseek,

	.release	= ftrace_pid_release,

};

kernel/trace/trace.c

+9 −5
Original line number Diff line number Diff line
@@ -3183,19 +3183,23 @@ tracing_write_stub(struct file *filp, const char __user *ubuf, 
	return count;

}



static loff_t tracing_seek(struct file *file, loff_t offset, int origin)

loff_t tracing_lseek(struct file *file, loff_t offset, int whence)

{

	int ret;



	if (file->f_mode & FMODE_READ)

		return seq_lseek(file, offset, origin);

		ret = seq_lseek(file, offset, whence);

	else

		return 0;

		file->f_pos = ret = 0;



	return ret;

}



static const struct file_operations tracing_fops = {

	.open		= tracing_open,

	.read		= seq_read,

	.write		= tracing_write_stub,

	.llseek		= tracing_seek,

	.llseek		= tracing_lseek,

	.release	= tracing_release,

};
@@ -4940,7 +4944,7 @@ static const struct file_operations snapshot_fops = { 
	.open		= tracing_snapshot_open,

	.read		= seq_read,

	.write		= tracing_snapshot_write,

	.llseek		= tracing_seek,

	.llseek		= tracing_lseek,

	.release	= tracing_snapshot_release,

};

kernel/trace/trace.h

+2 −0
Original line number Diff line number Diff line
@@ -588,6 +588,8 @@ void tracing_start_sched_switch_record(void); 
int register_tracer(struct tracer *type);

int is_tracing_stopped(void);



loff_t tracing_lseek(struct file *file, loff_t offset, int whence);



extern cpumask_var_t __read_mostly tracing_buffer_mask;



#define for_each_tracing_cpu(cpu)	\

kernel/trace/trace_events_trigger.c

+1 −1
Original line number Diff line number Diff line
@@ -281,7 +281,7 @@ const struct file_operations event_trigger_fops = { 
	.open = event_trigger_open,

	.read = seq_read,

	.write = event_trigger_write,

	.llseek = ftrace_filter_lseek,

	.llseek = tracing_lseek,

	.release = event_trigger_release,

};