Merge patch series "Minor namespace code simplication"

Joel Savitz <jsavitz@redhat.com> says:

The two patches are independent of each other. The first patch removes
unnecssary NULL guards from free_nsproxy() and create_new_namespaces()
in line with other usage of the put_*_ns() call sites. The second patch
slightly reduces the size of the kernel when CONFIG_CGROUPS is not
selected.

* patches from https://lore.kernel.org/20250508184930.183040-1-jsavitz@redhat.com:
  include/cgroup: separate {get,put}_cgroup_ns no-op case
  kernel/nsproxy: remove unnecessary guards

Link: https://lore.kernel.org/20250508184930.183040-1-jsavitz@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

2 files changed, 24 insertions, 32 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 28e999f2c642..8da19c3627b0 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -785,6 +785,17 @@ struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
 int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
 		   struct cgroup_namespace *ns);
 
+static inline void get_cgroup_ns(struct cgroup_namespace *ns)
+{
+	refcount_inc(&ns->ns.count);
+}
+
+static inline void put_cgroup_ns(struct cgroup_namespace *ns)
+{
+	if (refcount_dec_and_test(&ns->ns.count))
+		free_cgroup_ns(ns);
+}
+
 #else /* !CONFIG_CGROUPS */
 
 static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
@@ -795,19 +806,10 @@ copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
 	return old_ns;
 }
 
-#endif /* !CONFIG_CGROUPS */
+static inline void get_cgroup_ns(struct cgroup_namespace *ns) { }
+static inline void put_cgroup_ns(struct cgroup_namespace *ns) { }
 
-static inline void get_cgroup_ns(struct cgroup_namespace *ns)
-{
-	if (ns)
-		refcount_inc(&ns->ns.count);
-}
-
-static inline void put_cgroup_ns(struct cgroup_namespace *ns)
-{
-	if (ns && refcount_dec_and_test(&ns->ns.count))
-		free_cgroup_ns(ns);
-}
+#endif /* !CONFIG_CGROUPS */
 
 #ifdef CONFIG_CGROUPS
 
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index c9d97ed20122..5f31fdff8a38 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -128,17 +128,13 @@ out_time:
 out_net:
 	put_cgroup_ns(new_nsp->cgroup_ns);
 out_cgroup:
-	if (new_nsp->pid_ns_for_children)
-		put_pid_ns(new_nsp->pid_ns_for_children);
+	put_pid_ns(new_nsp->pid_ns_for_children);
 out_pid:
-	if (new_nsp->ipc_ns)
-		put_ipc_ns(new_nsp->ipc_ns);
+	put_ipc_ns(new_nsp->ipc_ns);
 out_ipc:
-	if (new_nsp->uts_ns)
-		put_uts_ns(new_nsp->uts_ns);
+	put_uts_ns(new_nsp->uts_ns);
 out_uts:
-	if (new_nsp->mnt_ns)
-		put_mnt_ns(new_nsp->mnt_ns);
+	put_mnt_ns(new_nsp->mnt_ns);
 out_ns:
 	kmem_cache_free(nsproxy_cachep, new_nsp);
 	return ERR_PTR(err);
@@ -189,18 +185,12 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
 
 void free_nsproxy(struct nsproxy *ns)
 {
-	if (ns->mnt_ns)
-		put_mnt_ns(ns->mnt_ns);
-	if (ns->uts_ns)
-		put_uts_ns(ns->uts_ns);
-	if (ns->ipc_ns)
-		put_ipc_ns(ns->ipc_ns);
-	if (ns->pid_ns_for_children)
-		put_pid_ns(ns->pid_ns_for_children);
-	if (ns->time_ns)
-		put_time_ns(ns->time_ns);
-	if (ns->time_ns_for_children)
-		put_time_ns(ns->time_ns_for_children);
+	put_mnt_ns(ns->mnt_ns);
+	put_uts_ns(ns->uts_ns);
+	put_ipc_ns(ns->ipc_ns);
+	put_pid_ns(ns->pid_ns_for_children);
+	put_time_ns(ns->time_ns);
+	put_time_ns(ns->time_ns_for_children);
 	put_cgroup_ns(ns->cgroup_ns);
 	put_net(ns->net_ns);
 	kmem_cache_free(nsproxy_cachep, ns);