netdev - [PATCH bpf-next v4 12/27] bpf: Factor out __bpf_trampoline

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Date:   Thu, 26 Aug 2021 21:39:07 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andriin@...com>,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...omium.org>, Daniel Xu <dxu@...uu.xyz>,
        Viktor Malik <vmalik@...hat.com>
Subject: [PATCH bpf-next v4 12/27] bpf: Factor out __bpf_trampoline_lookup function

Separating out __bpf_trampoline_lookup function, so it can
be used from other places in following patches.

Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 kernel/bpf/trampoline.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index f44899c9698a..6dba43266e0b 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -70,23 +70,37 @@ static void bpf_trampoline_init(struct bpf_trampoline *tr, u64 key)
 		INIT_HLIST_HEAD(&tr->progs_hlist[i]);
 }
 
-static struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
+static struct bpf_trampoline *__bpf_trampoline_lookup(u64 key)
 {
 	struct bpf_trampoline *tr;
 	struct hlist_head *head;
 
-	mutex_lock(&trampoline_mutex);
+	lockdep_assert_held(&trampoline_mutex);
+
 	head = &trampoline_table[hash_64(key, TRAMPOLINE_HASH_BITS)];
 	hlist_for_each_entry(tr, head, hlist) {
-		if (tr->key == key) {
-			refcount_inc(&tr->refcnt);
-			goto out;
-		}
+		if (tr->key == key)
+			return tr;
+	}
+	return NULL;
+}
+
+static struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
+{
+	struct bpf_trampoline *tr;
+	struct hlist_head *head;
+
+	mutex_lock(&trampoline_mutex);
+	tr = __bpf_trampoline_lookup(key);
+	if (tr) {
+		refcount_inc(&tr->refcnt);
+		goto out;
 	}
 	tr = kzalloc(sizeof(*tr), GFP_KERNEL);
 	if (!tr)
 		goto out;
 	bpf_trampoline_init(tr, key);
+	head = &trampoline_table[hash_64(key, TRAMPOLINE_HASH_BITS)];
 	hlist_add_head(&tr->hlist, head);
 out:
 	mutex_unlock(&trampoline_mutex);
-- 
2.31.1