uts: create "struct uts_namespace" from kmem_cache (3ea056c5) · Commits · 戴 / test

include/linux/utsname.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -44,6 +44,8 @@ static inline void put_uts_ns(struct uts_namespace *ns)
		{
		kref_put(&ns->kref, free_uts_ns);
		}

		void uts_ns_init(void);
		#else
		static inline void get_uts_ns(struct uts_namespace *ns)
		{
		@@ -61,6 +63,10 @@ static inline struct uts_namespace *copy_utsname(unsigned long flags,

		return old_ns;
		}

		static inline void uts_ns_init(void)
		{
		}
		#endif

		#ifdef CONFIG_PROC_SYSCTL

init/main.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -51,6 +51,7 @@
		#include <linux/taskstats_kern.h>
		#include <linux/delayacct.h>
		#include <linux/unistd.h>
		#include <linux/utsname.h>
		#include <linux/rmap.h>
		#include <linux/mempolicy.h>
		#include <linux/key.h>
		@@ -706,6 +707,7 @@ asmlinkage __visible void __init start_kernel(void)
		cred_init();
		fork_init();
		proc_caches_init();
		uts_ns_init();
		buffer_init();
		key_init();
		security_init();

kernel/utsname.c

+16 −4

Original line number	Diff line number	Diff line
		@@ -19,6 +19,8 @@
		#include <linux/proc_ns.h>
		#include <linux/sched/task.h>

		static struct kmem_cache *uts_ns_cache __ro_after_init;

		static struct ucounts inc_uts_namespaces(struct user_namespace ns)
		{
		return inc_ucount(ns, current_euid(), UCOUNT_UTS_NAMESPACES);
		@@ -33,7 +35,7 @@ static struct uts_namespace *create_uts_ns(void)
		{
		struct uts_namespace *uts_ns;

		uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
		uts_ns = kmem_cache_alloc(uts_ns_cache, GFP_KERNEL);
		if (uts_ns)
		kref_init(&uts_ns->kref);
		return uts_ns;
		@@ -42,7 +44,7 @@ static struct uts_namespace *create_uts_ns(void)
		/*
		* Clone a new ns copying an original utsname, setting refcount to 1
		* @old_ns: namespace to clone
		* Return ERR_PTR(-ENOMEM) on error (failure to kmalloc), new ns otherwise
		* Return ERR_PTR(-ENOMEM) on error (failure to allocate), new ns otherwise
		*/
		static struct uts_namespace clone_uts_ns(struct user_namespace user_ns,
		struct uts_namespace *old_ns)
		@@ -75,7 +77,7 @@ static struct uts_namespace clone_uts_ns(struct user_namespace user_ns,
		return ns;

		fail_free:
		kfree(ns);
		kmem_cache_free(uts_ns_cache, ns);
		fail_dec:
		dec_uts_namespaces(ucounts);
		fail:
		@@ -113,7 +115,7 @@ void free_uts_ns(struct kref *kref)
		dec_uts_namespaces(ns->ucounts);
		put_user_ns(ns->user_ns);
		ns_free_inum(&ns->ns);
		kfree(ns);
		kmem_cache_free(uts_ns_cache, ns);
		}

		static inline struct uts_namespace to_uts_ns(struct ns_common ns)
		@@ -169,3 +171,13 @@ const struct proc_ns_operations utsns_operations = {
		.install = utsns_install,
		.owner = utsns_owner,
		};

		void __init uts_ns_init(void)
		{
		uts_ns_cache = kmem_cache_create_usercopy(
		"uts_namespace", sizeof(struct uts_namespace), 0,
		SLAB_PANIC\|SLAB_ACCOUNT,
		offsetof(struct uts_namespace, name),
		sizeof_field(struct uts_namespace, name),
		NULL);
		}

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