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proc: task_state: move the main seq_printf() outside of rcu_read_lock()

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task_state() does seq_printf() under rcu_read_lock(), but this is only
needed for task_tgid_nr_ns() and task_numa_group_id().  We can calculate
tgid/ngid and drop rcu lock.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Cc: Sterling Alexander <stalexan@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roland McGrath <roland@hack.frob.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2014-12-10 15:45:15 -08:00 committed by Linus Torvalds
parent 0f4a0d53f2
commit b0fafc1111
1 changed files with 6 additions and 6 deletions
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12
fs/proc/array.c
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@ -158,7 +158,7 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
struct group_info *group_info;
int g;
const struct cred *cred;
pid_t ppid, tpid;
pid_t ppid, tpid, tgid, ngid;
unsigned int max_fds = 0;
rcu_read_lock();
@ -170,12 +170,16 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
if (tracer)
tpid = task_pid_nr_ns(tracer, ns);
}
tgid = task_tgid_nr_ns(p, ns);
ngid = task_numa_group_id(p);
cred = get_task_cred(p);
task_lock(p);
if (p->files)
max_fds = files_fdtable(p->files)->max_fds;
task_unlock(p);
rcu_read_unlock();
seq_printf(m,
"State:\t%s\n"
@ -188,10 +192,7 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
"Gid:\t%d\t%d\t%d\t%d\n"
"FDSize:\t%d\nGroups:\t",
get_task_state(p),
task_tgid_nr_ns(p, ns),
task_numa_group_id(p),
pid_nr_ns(pid, ns),
ppid, tpid,
tgid, ngid, pid_nr_ns(pid, ns), ppid, tpid,
from_kuid_munged(user_ns, cred->uid),
from_kuid_munged(user_ns, cred->euid),
from_kuid_munged(user_ns, cred->suid),
@ -201,7 +202,6 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
from_kgid_munged(user_ns, cred->sgid),
from_kgid_munged(user_ns, cred->fsgid),
max_fds);
rcu_read_unlock();
group_info = cred->group_info;
for (g = 0; g < group_info->ngroups; g++)