From: Joe Perches <joe@perches.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Will Deacon <will@kernel.org>
Subject: lockdep tracing and using of printk return value ?
Date: Tue, 19 May 2020 05:41:47 -0700 [thread overview]
Message-ID: <335067f871a85db5f24650a3dff96f19727bed50.camel@perches.com> (raw)
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, "");
next reply other threads:[~2020-05-19 12:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 12:41 Joe Perches [this message]
2020-05-19 14:45 ` Peter Zijlstra
2020-05-19 17:21 ` Joe Perches
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