kernel: rename is_single_threaded(task) to current_is_single_threaded(void)

- is_single_threaded(task) is not safe unless task == current,
  we can't use task->signal or task->mm.

- it doesn't make sense unless task == current, the task can
  fork right after the check.

Rename it to current_is_single_threaded() and kill the argument.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Oleg Nesterov 2009-07-10 03:48:23 +02:00 committed by James Morris
parent d2e3ee9b29
commit 5bb459bb45
4 changed files with 5 additions and 4 deletions

View file

@ -2075,7 +2075,7 @@ static inline unsigned long wait_task_inactive(struct task_struct *p,
#define for_each_process(p) \
for (p = &init_task ; (p = next_task(p)) != &init_task ; )
extern bool is_single_threaded(struct task_struct *);
extern bool current_is_single_threaded(void);
/*
* Careful: do_each_thread/while_each_thread is a double loop so

View file

@ -15,8 +15,9 @@
/*
* Returns true if the task does not share ->mm with another thread/process.
*/
bool is_single_threaded(struct task_struct *task)
bool current_is_single_threaded(void)
{
struct task_struct *task = current;
struct mm_struct *mm = task->mm;
struct task_struct *p, *t;
bool ret;

View file

@ -702,7 +702,7 @@ long join_session_keyring(const char *name)
/* only permit this if there's a single thread in the thread group -
* this avoids us having to adjust the creds on all threads and risking
* ENOMEM */
if (!is_single_threaded(current))
if (!current_is_single_threaded())
return -EMLINK;
new = prepare_creds();

View file

@ -5187,7 +5187,7 @@ static int selinux_setprocattr(struct task_struct *p,
/* Only allow single threaded processes to change context */
error = -EPERM;
if (!is_single_threaded(p)) {
if (!current_is_single_threaded()) {
error = security_bounded_transition(tsec->sid, sid);
if (error)
goto abort_change;