diff options
| author | Christian Brauner <brauner@kernel.org> | 2025-11-10 16:08:24 +0100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2025-11-11 10:01:31 +0100 |
| commit | 657aeb436d70c66583cb2b5b6c65ca64bcf503a8 (patch) | |
| tree | 3ff5d142ce303898b7553da9ea85e6ab59b3b088 | |
| parent | 3826d5dd06996007c13352b7fa65625ab570f651 (diff) | |
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: Christian Brauner <brauner@kernel.org>
| -rw-r--r-- | include/linux/ns_common.h | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h index b9e8f21a6984..5b8f2f0163d7 100644 --- a/include/linux/ns_common.h +++ b/include/linux/ns_common.h @@ -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) |