1 files changed, 10 insertions, 33 deletions

diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c
index b6587ec40f1b..7efdf5d770ca 100644
--- a/kernel/bpf/cpumask.c
+++ b/kernel/bpf/cpumask.c
@@ -9,6 +9,7 @@
 /**
  * struct bpf_cpumask - refcounted BPF cpumask wrapper structure
  * @cpumask:	The actual cpumask embedded in the struct.
+ * @rcu:	The RCU head used to free the cpumask with RCU safety.
  * @usage:	Object reference counter. When the refcount goes to 0, the
  *		memory is released back to the BPF allocator, which provides
  *		RCU safety.
@@ -24,6 +25,7 @@
  */
 struct bpf_cpumask {
 	cpumask_t cpumask;
+	struct rcu_head rcu;
 	refcount_t usage;
 };
 
@@ -80,32 +82,14 @@ __bpf_kfunc struct bpf_cpumask *bpf_cpumask_acquire(struct bpf_cpumask *cpumask)
 	return cpumask;
 }
 
-/**
- * bpf_cpumask_kptr_get() - Attempt to acquire a reference to a BPF cpumask
- *			    stored in a map.
- * @cpumaskp: A pointer to a BPF cpumask map value.
- *
- * Attempts to acquire a reference to a BPF cpumask stored in a map value. The
- * cpumask returned by this function must either be embedded in a map as a
- * kptr, or freed with bpf_cpumask_release(). This function may return NULL if
- * no BPF cpumask was found in the specified map value.
- */
-__bpf_kfunc struct bpf_cpumask *bpf_cpumask_kptr_get(struct bpf_cpumask **cpumaskp)
+static void cpumask_free_cb(struct rcu_head *head)
 {
 	struct bpf_cpumask *cpumask;
 
-	/* The BPF memory allocator frees memory backing its caches in an RCU
-	 * callback. Thus, we can safely use RCU to ensure that the cpumask is
-	 * safe to read.
-	 */
-	rcu_read_lock();
-
-	cpumask = READ_ONCE(*cpumaskp);
-	if (cpumask && !refcount_inc_not_zero(&cpumask->usage))
-		cpumask = NULL;
-
-	rcu_read_unlock();
-	return cpumask;
+	cpumask = container_of(head, struct bpf_cpumask, rcu);
+	migrate_disable();
+	bpf_mem_cache_free(&bpf_cpumask_ma, cpumask);
+	migrate_enable();
 }
 
 /**
@@ -118,14 +102,8 @@ __bpf_kfunc struct bpf_cpumask *bpf_cpumask_kptr_get(struct bpf_cpumask **cpumas
  */
 __bpf_kfunc void bpf_cpumask_release(struct bpf_cpumask *cpumask)
 {
-	if (!cpumask)
-		return;
-
-	if (refcount_dec_and_test(&cpumask->usage)) {
-		migrate_disable();
-		bpf_mem_cache_free(&bpf_cpumask_ma, cpumask);
-		migrate_enable();
-	}
+	if (refcount_dec_and_test(&cpumask->usage))
+		call_rcu(&cpumask->rcu, cpumask_free_cb);
 }
 
 /**
@@ -424,9 +402,8 @@ __diag_pop();
 
 BTF_SET8_START(cpumask_kfunc_btf_ids)
 BTF_ID_FLAGS(func, bpf_cpumask_create, KF_ACQUIRE | KF_RET_NULL)
-BTF_ID_FLAGS(func, bpf_cpumask_release, KF_RELEASE | KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_cpumask_release, KF_RELEASE)
 BTF_ID_FLAGS(func, bpf_cpumask_acquire, KF_ACQUIRE | KF_TRUSTED_ARGS)
-BTF_ID_FLAGS(func, bpf_cpumask_kptr_get, KF_ACQUIRE | KF_KPTR_GET | KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_cpumask_first, KF_RCU)
 BTF_ID_FLAGS(func, bpf_cpumask_first_zero, KF_RCU)
 BTF_ID_FLAGS(func, bpf_cpumask_set_cpu, KF_RCU)