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2024f91e96
Currently every namespace type has its own lifetime counter which is stored in the specific namespace struct. The lifetime counters are used identically for all namespaces types. Namespaces may of course have additional unrelated counters and these are not altered. This introduces a common lifetime counter into struct ns_common. The ns_common struct encompasses information that all namespaces share. That should include the lifetime counter since its common for all of them. It also allows us to unify the type of the counters across all namespaces. Most of them use refcount_t but one uses atomic_t and at least one uses kref. Especially the last one doesn't make much sense since it's just a wrapper around refcount_t since 2016 and actually complicates cleanup operations by having to use container_of() to cast the correct namespace struct out of struct ns_common. Having the lifetime counter for the namespaces in one place reduces maintenance cost. Not just because after switching all namespaces over we will have removed more code than we added but also because the logic is more easily understandable and we indicate to the user that the basic lifetime requirements for all namespaces are currently identical. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> [christian.brauner@ubuntu.com: rewrite commit & split into two patches] Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
16 lines
283 B
C
16 lines
283 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_NS_COMMON_H
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#define _LINUX_NS_COMMON_H
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#include <linux/refcount.h>
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struct proc_ns_operations;
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struct ns_common {
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atomic_long_t stashed;
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const struct proc_ns_operations *ops;
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unsigned int inum;
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refcount_t count;
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};
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#endif
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