Commit 06576edd authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

Removing has_group_leader_pid 



With de_thread now calling exchange_tids has_group_leader_pid no longer
makes any sense and is equivalent to calling thread_group_leader.

As there are only 2 remaining users of has_group_leader_pid let's
update the code and get rid of has_group_leader_pid.

There is one extra patch to lookup_task that performs that unifies
to code paths that become identical when has_group_leader_pid went
away.

Eric W. Biederman (4):
      posix-cpu-timer: Tidy up group_leader logic in lookup_task
      posix-cpu-timer:  Unify the now redundant code in lookup_task
      exec: Remove BUG_ON(has_group_leader_pid)
      signal: Remove has_group_leader_pid

 fs/exec.c                      |  1 -
 include/linux/sched/signal.h   | 11 -----------
 kernel/time/posix-cpu-timers.c | 21 ++++++++-------------
 3 files changed, 8 insertions(+), 25 deletions(-)

Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parents 50712280 bbd40fc4

fs/exec.c

+0 −1
Original line number Diff line number Diff line
@@ -1176,7 +1176,6 @@ static int de_thread(struct task_struct *tsk) 
		tsk->start_boottime = leader->start_boottime;



		BUG_ON(!same_thread_group(leader, tsk));

		BUG_ON(has_group_leader_pid(tsk));

		/*

		 * An exec() starts a new thread group with the

		 * TGID of the previous thread group. Rehash the

include/linux/sched/signal.h

+0 −11
Original line number Diff line number Diff line
@@ -654,17 +654,6 @@ static inline bool thread_group_leader(struct task_struct *p) 
	return p->exit_signal >= 0;

}



/* Do to the insanities of de_thread it is possible for a process

 * to have the pid of the thread group leader without actually being

 * the thread group leader.  For iteration through the pids in proc

 * all we care about is that we have a task with the appropriate

 * pid, we don't actually care if we have the right task.

 */

static inline bool has_group_leader_pid(struct task_struct *p)

{

	return task_pid(p) == task_tgid(p);

}



static inline

bool same_thread_group(struct task_struct *p1, struct task_struct *p2)

{

kernel/time/posix-cpu-timers.c

+8 −13
Original line number Diff line number Diff line
@@ -66,23 +66,18 @@ static struct task_struct *lookup_task(const pid_t pid, bool thread, 
	if (thread)

		return same_thread_group(p, current) ? p : NULL;



	if (gettime) {

	/*

	 * For clock_gettime(PROCESS) the task does not need to be

		 * the actual group leader. tsk->sighand gives

	 * the actual group leader. task->signal gives

	 * access to the group's clock.

		 *

		 * Timers need the group leader because they take a

		 * reference on it and store the task pointer until the

		 * timer is destroyed.

	 */

		return (p == current || thread_group_leader(p)) ? p : NULL;

	}

	if (gettime && (p == current))

		return p;



	/*

	 * For processes require that p is group leader.

	 */

	return has_group_leader_pid(p) ? p : NULL;

	return thread_group_leader(p) ? p : NULL;

}



static struct task_struct *__get_task_for_clock(const clockid_t clock,

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