linux-kernel - [PATCH bpf-next 2/3] bpf: Remove now-unnecessary NULL checks for KF

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Date:   Sat, 25 Mar 2023 16:31:45 -0500
From:   David Vernet <void@...ifault.com>
To:     bpf@...r.kernel.org
Cc:     ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
        martin.lau@...ux.dev, song@...nel.org, yhs@...com,
        john.fastabend@...il.com, kpsingh@...nel.org, sdf@...gle.com,
        haoluo@...gle.com, jolsa@...nel.org, linux-kernel@...r.kernel.org,
        kernel-team@...a.com
Subject: [PATCH bpf-next 2/3] bpf: Remove now-unnecessary NULL checks for KF_RELEASE kfuncs

Now that we're not invoking kfunc destructors when the kptr in a map was
NULL, we no longer require NULL checks in many of our KF_RELEASE kfuncs.
This patch removes those NULL checks.

Signed-off-by: David Vernet <void@...ifault.com>
---
 drivers/hid/bpf/hid_bpf_dispatch.c | 3 ---
 kernel/bpf/cpumask.c               | 3 ---
 kernel/bpf/helpers.c               | 6 ------
 net/bpf/test_run.c                 | 3 ---
 net/netfilter/nf_conntrack_bpf.c   | 2 --
 5 files changed, 17 deletions(-)

diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c
index 8a034a555d4c..d9ef45fcaeab 100644
--- a/drivers/hid/bpf/hid_bpf_dispatch.c
+++ b/drivers/hid/bpf/hid_bpf_dispatch.c
@@ -342,9 +342,6 @@ hid_bpf_release_context(struct hid_bpf_ctx *ctx)
 {
 	struct hid_bpf_ctx_kern *ctx_kern;
 
-	if (!ctx)
-		return;
-
 	ctx_kern = container_of(ctx, struct hid_bpf_ctx_kern, ctx);
 
 	kfree(ctx_kern);
diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c
index db9da2194c1a..e991af7dc13c 100644
--- a/kernel/bpf/cpumask.c
+++ b/kernel/bpf/cpumask.c
@@ -102,9 +102,6 @@ static void cpumask_free_cb(struct rcu_head *head)
  */
 __bpf_kfunc void bpf_cpumask_release(struct bpf_cpumask *cpumask)
 {
-	if (!cpumask)
-		return;
-
 	if (refcount_dec_and_test(&cpumask->usage))
 		call_rcu(&cpumask->rcu, cpumask_free_cb);
 }
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index f753676ef652..8980f6859443 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2089,9 +2089,6 @@ __bpf_kfunc struct task_struct *bpf_task_kptr_get(struct task_struct **pp)
  */
 __bpf_kfunc void bpf_task_release(struct task_struct *p)
 {
-	if (!p)
-		return;
-
 	put_task_struct(p);
 }
 
@@ -2148,9 +2145,6 @@ __bpf_kfunc struct cgroup *bpf_cgroup_kptr_get(struct cgroup **cgrpp)
  */
 __bpf_kfunc void bpf_cgroup_release(struct cgroup *cgrp)
 {
-	if (!cgrp)
-		return;
-
 	cgroup_put(cgrp);
 }
 
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 8d6b31209bd6..27587f1c5f36 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -615,9 +615,6 @@ bpf_kfunc_call_memb_acquire(void)
 
 __bpf_kfunc void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p)
 {
-	if (!p)
-		return;
-
 	refcount_dec(&p->cnt);
 }
 
diff --git a/net/netfilter/nf_conntrack_bpf.c b/net/netfilter/nf_conntrack_bpf.c
index cd99e6dc1f35..002e9d24a1e9 100644
--- a/net/netfilter/nf_conntrack_bpf.c
+++ b/net/netfilter/nf_conntrack_bpf.c
@@ -401,8 +401,6 @@ __bpf_kfunc struct nf_conn *bpf_ct_insert_entry(struct nf_conn___init *nfct_i)
  */
 __bpf_kfunc void bpf_ct_release(struct nf_conn *nfct)
 {
-	if (!nfct)
-		return;
 	nf_ct_put(nfct);
 }
 
-- 
2.39.0