Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
+22
-3
+22
-3
include/linux/ns_common.h
+22
-3
include/linux/ns_common.h
···
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static __always_inline __must_check bool __ns_ref_put(struct ns_common *ns)
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{
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+
if (is_ns_init_id(ns))
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+
return false;
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if (refcount_dec_and_test(&ns->__ns_ref)) {
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VFS_WARN_ON_ONCE(__ns_ref_active_read(ns));
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return true;
···
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static __always_inline __must_check bool __ns_ref_get(struct ns_common *ns)
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73
{
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+
if (is_ns_init_id(ns))
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+
return true;
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if (refcount_inc_not_zero(&ns->__ns_ref))
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return true;
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VFS_WARN_ON_ONCE(__ns_ref_active_read(ns));
···
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return refcount_read(&ns->__ns_ref);
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}
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+
static __always_inline void __ns_ref_inc(struct ns_common *ns)
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+
{
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+
if (is_ns_init_id(ns))
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+
return;
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+
refcount_inc(&ns->__ns_ref);
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+
}
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+
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+
static __always_inline __must_check bool __ns_ref_dec_and_lock(struct ns_common *ns,
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+
spinlock_t *ns_lock)
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+
{
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+
if (is_ns_init_id(ns))
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+
return false;
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+
return refcount_dec_and_lock(&ns->__ns_ref, ns_lock);
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+
}
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+
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#define ns_ref_read(__ns) __ns_ref_read(to_ns_common((__ns)))
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-
#define ns_ref_inc(__ns) refcount_inc(&to_ns_common((__ns))->__ns_ref)
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+
#define ns_ref_inc(__ns) __ns_ref_inc(to_ns_common((__ns)))
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#define ns_ref_get(__ns) __ns_ref_get(to_ns_common((__ns)))
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#define ns_ref_put(__ns) __ns_ref_put(to_ns_common((__ns)))
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-
#define ns_ref_put_and_lock(__ns, __lock) \
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-
refcount_dec_and_lock(&to_ns_common((__ns))->__ns_ref, (__lock))
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+
#define ns_ref_put_and_lock(__ns, __ns_lock) \
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+
__ns_ref_dec_and_lock(to_ns_common((__ns)), __ns_lock)
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#define ns_ref_active_read(__ns) \
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((__ns) ? __ns_ref_active_read(to_ns_common(__ns)) : 0)