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    SubjectRe: [CFT][PATCH 6/8] userns: Rename id_map_mutex to userns_state_mutex
    On Tue, Dec 9, 2014 at 12:41 PM, Eric W. Biederman
    <ebiederm@xmission.com> wrote:
    >
    > Generalize id_map_mutex so it can be used for more state of a user namespace.

    Reviewed-by: Andy Lutomirski <luto@amacapital.net>

    >
    > Cc: stable@vger.kernel.org
    > Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
    > ---
    > kernel/user_namespace.c | 14 ++++++--------
    > 1 file changed, 6 insertions(+), 8 deletions(-)
    >
    > diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
    > index 1e34de2fbd60..44a555ac6104 100644
    > --- a/kernel/user_namespace.c
    > +++ b/kernel/user_namespace.c
    > @@ -24,6 +24,7 @@
    > #include <linux/fs_struct.h>
    >
    > static struct kmem_cache *user_ns_cachep __read_mostly;
    > +static DEFINE_MUTEX(userns_state_mutex);
    >
    > static bool new_idmap_permitted(const struct file *file,
    > struct user_namespace *ns, int cap_setid,
    > @@ -583,9 +584,6 @@ static bool mappings_overlap(struct uid_gid_map *new_map,
    > return false;
    > }
    >
    > -
    > -static DEFINE_MUTEX(id_map_mutex);
    > -
    > static ssize_t map_write(struct file *file, const char __user *buf,
    > size_t count, loff_t *ppos,
    > int cap_setid,
    > @@ -602,7 +600,7 @@ static ssize_t map_write(struct file *file, const char __user *buf,
    > ssize_t ret = -EINVAL;
    >
    > /*
    > - * The id_map_mutex serializes all writes to any given map.
    > + * The userns_state_mutex serializes all writes to any given map.
    > *
    > * Any map is only ever written once.
    > *
    > @@ -620,7 +618,7 @@ static ssize_t map_write(struct file *file, const char __user *buf,
    > * order and smp_rmb() is guaranteed that we don't have crazy
    > * architectures returning stale data.
    > */
    > - mutex_lock(&id_map_mutex);
    > + mutex_lock(&userns_state_mutex);
    >
    > ret = -EPERM;
    > /* Only allow one successful write to the map */
    > @@ -750,7 +748,7 @@ static ssize_t map_write(struct file *file, const char __user *buf,
    > *ppos = count;
    > ret = count;
    > out:
    > - mutex_unlock(&id_map_mutex);
    > + mutex_unlock(&userns_state_mutex);
    > if (page)
    > free_page(page);
    > return ret;
    > @@ -845,12 +843,12 @@ bool userns_may_setgroups(const struct user_namespace *ns)
    > {
    > bool allowed;
    >
    > - mutex_lock(&id_map_mutex);
    > + mutex_lock(&userns_state_mutex);
    > /* It is not safe to use setgroups until a gid mapping in
    > * the user namespace has been established.
    > */
    > allowed = ns->gid_map.nr_extents != 0;
    > - mutex_unlock(&id_map_mutex);
    > + mutex_unlock(&userns_state_mutex);
    >
    > return allowed;
    > }
    > --
    > 1.9.1
    >



    --
    Andy Lutomirski
    AMA Capital Management, LLC


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