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>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 59bf5b5..e32a2f4 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3183,19 +3183,23 @@
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 @@
.open = tracing_snapshot_open,
.read = seq_read,
.write = tracing_snapshot_write,
- .llseek = tracing_seek,
+ .llseek = tracing_lseek,
.release = tracing_snapshot_release,
};