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: kbuild test robot <fengguang.wu@intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 0 insertions, 2 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 31ea4b4..f4233b1 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -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);