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Sender: Namhyung Kim <namhyung@gmail.com>
From:   Namhyung Kim <namhyung@kernel.org>
To:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>, Will Deacon <will@kernel.org>,
        Waiman Long <longman@redhat.com>,
        Boqun Feng <boqun.feng@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Steven Rostedt <rostedt@goodmis.org>,
        Byungchul Park <byungchul.park@lge.com>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Radoslaw Burny <rburny@google.com>, Chris Mason <clm@fb.com>,
        Josef Bacik <josef@toxicpanda.com>,
        linux-btrfs@vger.kernel.org, David Sterba <dsterba@suse.com>
Subject: [PATCH 06/12] btrfs: change lockdep class size check using ks->names
Date:   Tue,  8 Feb 2022 11:43:18 -0800
Message-Id: <20220208194324.85333-7-namhyung@kernel.org>
In-Reply-To: <20220208194324.85333-1-namhyung@kernel.org>
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With upcoming lock tracepoints config, it'd allow some lockdep
annotation code without enabling CONFIG_LOCKDEP actually.  In that
config, size of the struct lock_class_key would be 0.

But it'd cause divide-by-zero in btrfs_set_buffer_lockdep_class() due
to ARRAY_SIZE macro.  Let's change it to use ks->names[] instead.  It
should have the same size as with ks->keys[].

Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: linux-btrfs@vger.kernel.org
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 fs/btrfs/disk-io.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 87a5addbedf6..be41e35bee92 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -190,7 +190,7 @@ void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
 {
 	struct btrfs_lockdep_keyset *ks;
 
-	BUG_ON(level >= ARRAY_SIZE(ks->keys));
+	BUG_ON(level >= ARRAY_SIZE(ks->names));
 
 	/* find the matching keyset, id 0 is the default entry */
 	for (ks = btrfs_lockdep_keysets; ks->id; ks++)
-- 
2.35.0.263.gb82422642f-goog