netdev - [PATCH net-next 1/6] bpf: bpf_lock needs only block bottom half

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Date:   Wed, 26 Apr 2017 20:24:14 +0200
From:   Hannes Frederic Sowa <hannes@...essinduktion.org>
To:     netdev@...r.kernel.org
Cc:     ast@...nel.org, daniel@...earbox.com, jbenc@...hat.com,
        aconole@...heb.org
Subject: [PATCH net-next 1/6] bpf: bpf_lock needs only block bottom half

We never modify bpf programs from hardirqs ever.

Signed-off-by: Hannes Frederic Sowa <hannes@...essinduktion.org>
---
 kernel/bpf/core.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index b4f1cb0c5ac710..6f81e0f5a0faa2 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -394,27 +394,23 @@ static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
 
 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
 {
-	unsigned long flags;
-
 	if (!bpf_prog_kallsyms_candidate(fp) ||
 	    !capable(CAP_SYS_ADMIN))
 		return;
 
-	spin_lock_irqsave(&bpf_lock, flags);
+	spin_lock_bh(&bpf_lock);
 	bpf_prog_ksym_node_add(fp->aux);
-	spin_unlock_irqrestore(&bpf_lock, flags);
+	spin_unlock_bh(&bpf_lock);
 }
 
 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
 {
-	unsigned long flags;
-
 	if (!bpf_prog_kallsyms_candidate(fp))
 		return;
 
-	spin_lock_irqsave(&bpf_lock, flags);
+	spin_lock_bh(&bpf_lock);
 	bpf_prog_ksym_node_del(fp->aux);
-	spin_unlock_irqrestore(&bpf_lock, flags);
+	spin_unlock_bh(&bpf_lock);
 }
 
 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
-- 
2.9.3