Unverified Commit 657aeb43 authored by Christian Brauner's avatar Christian Brauner
Browse files

ns: make all reference counts on initial namespace a nop 

They are always active so no need to needlessly cacheline ping-pong.

Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-12-e8a9264e0fb9@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 3826d5dd

include/linux/ns_common.h

+22 −3
Original line number Diff line number Diff line
@@ -62,6 +62,8 @@ static __always_inline __must_check int __ns_ref_active_read(const struct ns_com 


static __always_inline __must_check bool __ns_ref_put(struct ns_common *ns)

{

	if (is_ns_init_id(ns))

		return false;

	if (refcount_dec_and_test(&ns->__ns_ref)) {

		VFS_WARN_ON_ONCE(__ns_ref_active_read(ns));

		return true;
@@ -71,6 +73,8 @@ static __always_inline __must_check bool __ns_ref_put(struct ns_common *ns) 


static __always_inline __must_check bool __ns_ref_get(struct ns_common *ns)

{

	if (is_ns_init_id(ns))

		return true;

	if (refcount_inc_not_zero(&ns->__ns_ref))

		return true;

	VFS_WARN_ON_ONCE(__ns_ref_active_read(ns));
@@ -82,12 +86,27 @@ static __always_inline __must_check int __ns_ref_read(const struct ns_common *ns 
	return refcount_read(&ns->__ns_ref);

}



static __always_inline void __ns_ref_inc(struct ns_common *ns)

{

	if (is_ns_init_id(ns))

		return;

	refcount_inc(&ns->__ns_ref);

}



static __always_inline __must_check bool __ns_ref_dec_and_lock(struct ns_common *ns,

							       spinlock_t *ns_lock)

{

	if (is_ns_init_id(ns))

		return false;

	return refcount_dec_and_lock(&ns->__ns_ref, ns_lock);

}



#define ns_ref_read(__ns) __ns_ref_read(to_ns_common((__ns)))

#define ns_ref_inc(__ns) refcount_inc(&to_ns_common((__ns))->__ns_ref)

#define ns_ref_inc(__ns) __ns_ref_inc(to_ns_common((__ns)))

#define ns_ref_get(__ns) __ns_ref_get(to_ns_common((__ns)))

#define ns_ref_put(__ns) __ns_ref_put(to_ns_common((__ns)))

#define ns_ref_put_and_lock(__ns, __lock) \

	refcount_dec_and_lock(&to_ns_common((__ns))->__ns_ref, (__lock))

#define ns_ref_put_and_lock(__ns, __ns_lock) \

	__ns_ref_dec_and_lock(to_ns_common((__ns)), __ns_lock)



#define ns_ref_active_read(__ns) \

	((__ns) ? __ns_ref_active_read(to_ns_common(__ns)) : 0)