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From: Christian Brauner <christian.brauner@ubuntu.com>
To: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: viro@zeniv.linux.org.uk, adobriyan@gmail.com,
	davem@davemloft.net, ebiederm@xmission.com,
	akpm@linux-foundation.org, areber@redhat.com, serge@hallyn.com,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 05/23] user: Use generic ns_common::count
Date: Thu, 30 Jul 2020 16:46:41 +0200
Message-ID: <20200730144641.rep2ht5lmnryfhzj@wittgenstein> (raw)
In-Reply-To: <159611038719.535980.13960315152927389105.stgit@localhost.localdomain>

On Thu, Jul 30, 2020 at 02:59:47PM +0300, Kirill Tkhai wrote:
> Convert user namespace to use generic counter.
> 
> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
> ---

Looks good!
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>

>  include/linux/user_namespace.h |    5 ++---
>  kernel/user.c                  |    2 +-
>  kernel/user_namespace.c        |    4 ++--
>  3 files changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
> index 6ef1c7109fc4..64cf8ebdc4ec 100644
> --- a/include/linux/user_namespace.h
> +++ b/include/linux/user_namespace.h
> @@ -57,7 +57,6 @@ struct user_namespace {
>  	struct uid_gid_map	uid_map;
>  	struct uid_gid_map	gid_map;
>  	struct uid_gid_map	projid_map;
> -	atomic_t		count;
>  	struct user_namespace	*parent;
>  	int			level;
>  	kuid_t			owner;
> @@ -109,7 +108,7 @@ void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
>  static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
>  {
>  	if (ns)
> -		atomic_inc(&ns->count);
> +		refcount_inc(&ns->ns.count);
>  	return ns;
>  }
>  
> @@ -119,7 +118,7 @@ extern void __put_user_ns(struct user_namespace *ns);
>  
>  static inline void put_user_ns(struct user_namespace *ns)
>  {
> -	if (ns && atomic_dec_and_test(&ns->count))
> +	if (ns && refcount_dec_and_test(&ns->ns.count))
>  		__put_user_ns(ns);
>  }
>  
> diff --git a/kernel/user.c b/kernel/user.c
> index b1635d94a1f2..a2478cddf536 100644
> --- a/kernel/user.c
> +++ b/kernel/user.c
> @@ -55,7 +55,7 @@ struct user_namespace init_user_ns = {
>  			},
>  		},
>  	},
> -	.count = ATOMIC_INIT(3),
> +	.ns.count = REFCOUNT_INIT(3),

Note-to-self: I really wish we'd had a comment in cases where the
refcount isn't set to 1 but to something like 3. Otherwise one always
needs to dig up the reasons why. :)

>  	.owner = GLOBAL_ROOT_UID,
>  	.group = GLOBAL_ROOT_GID,
>  	.ns.inum = PROC_USER_INIT_INO,
> diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
> index 87804e0371fe..7c2bbe8f3e45 100644
> --- a/kernel/user_namespace.c
> +++ b/kernel/user_namespace.c
> @@ -111,7 +111,7 @@ int create_user_ns(struct cred *new)
>  		goto fail_free;
>  	ns->ns.ops = &userns_operations;
>  
> -	atomic_set(&ns->count, 1);
> +	refcount_set(&ns->ns.count, 1);
>  	/* Leave the new->user_ns reference with the new user namespace. */
>  	ns->parent = parent_ns;
>  	ns->level = parent_ns->level + 1;
> @@ -197,7 +197,7 @@ static void free_user_ns(struct work_struct *work)
>  		kmem_cache_free(user_ns_cachep, ns);
>  		dec_user_namespaces(ucounts);
>  		ns = parent;
> -	} while (atomic_dec_and_test(&parent->count));
> +	} while (refcount_dec_and_test(&parent->ns.count));
>  }
>  
>  void __put_user_ns(struct user_namespace *ns)
> 
> 

  reply index

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-30 11:59 [PATCH 00/23] proc: Introduce /proc/namespaces/ directory to expose namespaces lineary Kirill Tkhai
2020-07-30 11:59 ` [PATCH 01/23] ns: Add common refcount into ns_common add use it as counter for net_ns Kirill Tkhai
2020-07-30 13:35   ` Christian Brauner
2020-07-30 14:07     ` Kirill Tkhai
2020-07-30 15:59       ` Christian Brauner
2020-07-30 14:30   ` Christian Brauner
2020-07-30 14:34     ` Kirill Tkhai
2020-07-30 14:39       ` Christian Brauner
2020-07-30 11:59 ` [PATCH 02/23] uts: Use generic ns_common::count Kirill Tkhai
2020-07-30 14:30   ` Christian Brauner
2020-07-30 11:59 ` [PATCH 03/23] ipc: " Kirill Tkhai
2020-07-30 14:32   ` Christian Brauner
2020-07-30 11:59 ` [PATCH 04/23] pid: " Kirill Tkhai
2020-07-30 14:37   ` Christian Brauner
2020-07-30 11:59 ` [PATCH 05/23] user: " Kirill Tkhai
2020-07-30 14:46   ` Christian Brauner [this message]
2020-07-30 11:59 ` [PATCH 06/23] mnt: " Kirill Tkhai
2020-07-30 14:49   ` Christian Brauner
2020-07-30 11:59 ` [PATCH 07/23] cgroup: " Kirill Tkhai
2020-07-30 14:50   ` Christian Brauner
2020-07-30 12:00 ` [PATCH 08/23] time: " Kirill Tkhai
2020-07-30 14:52   ` Christian Brauner
2020-07-30 12:00 ` [PATCH 09/23] ns: Introduce ns_idr to be able to iterate all allocated namespaces in the system Kirill Tkhai
2020-07-30 12:23   ` Matthew Wilcox
2020-07-30 13:32     ` Kirill Tkhai
2020-07-30 13:56       ` Matthew Wilcox
2020-07-30 14:12         ` Kirill Tkhai
2020-07-30 14:15           ` Matthew Wilcox
2020-07-30 14:20             ` Kirill Tkhai
2020-07-30 12:00 ` [PATCH 10/23] fs: Rename fs/proc/namespaces.c into fs/proc/task_namespaces.c Kirill Tkhai
2020-07-30 12:00 ` [PATCH 11/23] fs: Add /proc/namespaces/ directory Kirill Tkhai
2020-07-30 12:18   ` Alexey Dobriyan
2020-07-30 13:22     ` Kirill Tkhai
2020-07-30 13:26   ` Christian Brauner
2020-07-30 14:30     ` Kirill Tkhai
2020-07-30 20:47   ` kernel test robot
2020-07-30 22:20   ` kernel test robot
2020-08-05  8:17   ` kernel test robot
2020-08-05  8:17   ` [RFC PATCH] fs: namespaces_dentry_operations can be static kernel test robot
2020-07-30 12:00 ` [PATCH 12/23] user: Free user_ns one RCU grace period after final counter put Kirill Tkhai
2020-07-30 12:00 ` [PATCH 13/23] user: Add user namespaces into ns_idr Kirill Tkhai
2020-07-30 12:00 ` [PATCH 14/23] net: Add net " Kirill Tkhai
2020-07-30 12:00 ` [PATCH 15/23] pid: Eextract child_reaper check from pidns_for_children_get() Kirill Tkhai
2020-07-30 12:00 ` [PATCH 16/23] proc_ns_operations: Add can_get method Kirill Tkhai
2020-07-30 12:00 ` [PATCH 17/23] pid: Add pid namespaces into ns_idr Kirill Tkhai
2020-07-30 12:00 ` [PATCH 18/23] uts: Free uts namespace one RCU grace period after final counter put Kirill Tkhai
2020-07-30 12:01 ` [PATCH 19/23] uts: Add uts namespaces into ns_idr Kirill Tkhai
2020-07-30 12:01 ` [PATCH 20/23] ipc: Add ipc " Kirill Tkhai
2020-07-30 12:01 ` [PATCH 21/23] mnt: Add mount " Kirill Tkhai
2020-07-30 12:01 ` [PATCH 22/23] cgroup: Add cgroup " Kirill Tkhai
2020-07-30 12:01 ` [PATCH 23/23] time: Add time " Kirill Tkhai
2020-07-30 13:08 ` [PATCH 00/23] proc: Introduce /proc/namespaces/ directory to expose namespaces lineary Christian Brauner
2020-07-30 13:38   ` Christian Brauner
2020-07-30 14:34 ` Eric W. Biederman
2020-07-30 14:42   ` Christian Brauner
2020-07-30 15:01   ` Kirill Tkhai
2020-07-30 22:13     ` Eric W. Biederman
2020-07-31  8:48       ` Pavel Tikhomirov
2020-08-03 10:03       ` Kirill Tkhai
2020-08-03 10:51         ` Alexey Dobriyan
2020-08-06  8:05         ` Andrei Vagin
2020-08-07  8:47           ` Kirill Tkhai
2020-08-10 17:34             ` Andrei Vagin
2020-08-11 10:23               ` Kirill Tkhai
2020-08-12 17:53                 ` Andrei Vagin
2020-08-13  8:12                   ` Kirill Tkhai
2020-08-14  1:16                     ` Andrei Vagin
2020-08-14 15:11                       ` Kirill Tkhai
2020-08-14 19:21                         ` Andrei Vagin
2020-08-17 14:05                           ` Kirill Tkhai
2020-08-17 15:48                             ` Eric W. Biederman
2020-08-17 17:47                               ` Christian Brauner
2020-08-17 18:53                                 ` Eric W. Biederman
2020-08-04  5:43     ` Andrei Vagin
2020-08-04 12:11       ` Pavel Tikhomirov
2020-08-04 14:47       ` Kirill Tkhai

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