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From:   Daniel Xu <dxu@dxuuu.xyz>
To:     kuba@kernel.org, steffen.klassert@secunet.com,
        john.fastabend@gmail.com, Herbert Xu <herbert@gondor.apana.org.au>,
        davem@davemloft.net, hawk@kernel.org, daniel@iogearbox.net,
        pabeni@redhat.com, edumazet@google.com, ast@kernel.org,
        antony.antony@secunet.com, alexei.starovoitov@gmail.com,
        yonghong.song@linux.dev, eddyz87@gmail.com
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        bpf@vger.kernel.org, devel@linux-ipsec.org
Subject: [PATCH ipsec-next v2 2/6] bpf: xfrm: Add bpf_xdp_xfrm_state_release() kfunc
Date:   Tue, 28 Nov 2023 10:54:22 -0700
Message-ID: <e35bf393128407bf75e9d2fb9dca6c8e31c2a677.1701193577.git.dxu@dxuuu.xyz>
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This kfunc releases a previously acquired xfrm_state from
bpf_xdp_get_xfrm_state().

Co-developed-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Antony Antony <antony.antony@secunet.com>
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
---
 net/xfrm/xfrm_state_bpf.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/net/xfrm/xfrm_state_bpf.c b/net/xfrm/xfrm_state_bpf.c
index 1681825db506..1485b9da9425 100644
--- a/net/xfrm/xfrm_state_bpf.c
+++ b/net/xfrm/xfrm_state_bpf.c
@@ -94,10 +94,26 @@ bpf_xdp_get_xfrm_state(struct xdp_md *ctx, struct bpf_xfrm_state_opts *opts, u32
 	return x;
 }
 
+/* bpf_xdp_xfrm_state_release - Release acquired xfrm_state object
+ *
+ * This must be invoked for referenced PTR_TO_BTF_ID, and the verifier rejects
+ * the program if any references remain in the program in all of the explored
+ * states.
+ *
+ * Parameters:
+ * @x		- Pointer to referenced xfrm_state object, obtained using
+ *		  bpf_xdp_get_xfrm_state.
+ */
+__bpf_kfunc void bpf_xdp_xfrm_state_release(struct xfrm_state *x)
+{
+	xfrm_state_put(x);
+}
+
 __bpf_kfunc_end_defs();
 
 BTF_SET8_START(xfrm_state_kfunc_set)
 BTF_ID_FLAGS(func, bpf_xdp_get_xfrm_state, KF_RET_NULL | KF_ACQUIRE)
+BTF_ID_FLAGS(func, bpf_xdp_xfrm_state_release, KF_RELEASE)
 BTF_SET8_END(xfrm_state_kfunc_set)
 
 static const struct btf_kfunc_id_set xfrm_state_xdp_kfunc_set = {
-- 
2.42.1