lockdep tracing and using of printk return value ?

From: Joe Perches
Date: Tue May 19 2020 - 08:41:52 EST


Except for some ancient code in drivers/scsi, this code
may be the only kernel use of the printk return value.

Code that uses the printk return value in
kernel/locking/lockdep.c is odd because the printk
return length includes both the length of a KERN_<LEVEL>
prefix and the newline. depth also seems double counted.

Perhaps there's a better way to calculate this?

Maybe:
---
kernel/locking/lockdep.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 2fadc2635946..265227edc550 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1960,11 +1960,9 @@ static void print_lock_class_header(struct lock_class *class, int depth)

for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
if (class->usage_mask & (1 << bit)) {
- int len = depth;
-
- len += printk("%*s %s", depth, "", usage_str[bit]);
- len += printk(KERN_CONT " at:\n");
- print_lock_trace(class->usage_traces[bit], len);
+ printk("%*s %s at:\n", depth, "", usage_str[bit]);
+ print_lock_trace(class->usage_traces[bit],
+ depth + 3 + strlen(usage_str[bit]);
}
}
printk("%*s }\n", depth, "");