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authorEric W. Biederman <ebiederm@xmission.com>2006-03-29 04:11:03 +0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-29 06:36:40 +0400
commitd73d65293e3e2de7e916a89c8da30be0948afab7 (patch)
tree62b0ca76e3099c927f2960856dd060b136a8ccef /fs/exec.c
parent652486fb84a07ed750f1c11639518f55808bf555 (diff)
downloadlinux-d73d65293e3e2de7e916a89c8da30be0948afab7.tar.xz
[PATCH] pidhash: kill switch_exec_pids
switch_exec_pids is only called from de_thread by way of exec, and it is only called when we are exec'ing from a non thread group leader. Currently switch_exec_pids gives the leader the pid of the thread and unhashes and rehashes all of the process groups. The leader is already in the EXIT_DEAD state so no one cares about it's pids. The only concern for the leader is that __unhash_process called from release_task will function correctly. If we don't touch the leader at all we know that __unhash_process will work fine so there is no need to touch the leader. For the task becomming the thread group leader, we just need to give it the pid of the old thread group leader, add it to the task list, and attach it to the session and the process group of the thread group. Currently de_thread is also adding the task to the task list which is just silly. Currently the only leader of __detach_pid besides detach_pid is switch_exec_pids because of the ugly extra work that was being performed. So this patch removes switch_exec_pids because it is doing too much, it is creating an unnecessary special case in pid.c, duing work duplicated in de_thread, and generally obscuring what it is going on. The necessary work is added to de_thread, and it seems to be a little clearer there what is going on. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Kirill Korotaev <dev@sw.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/fs/exec.c b/fs/exec.c
index dd194923c52c..db0769447d33 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -708,7 +708,17 @@ static int de_thread(struct task_struct *tsk)
remove_parent(current);
remove_parent(leader);
- switch_exec_pids(leader, current);
+
+ /* Become a process group leader with the old leader's pid.
+ * Note: The old leader also uses thispid until release_task
+ * is called. Odd but simple and correct.
+ */
+ detach_pid(current, PIDTYPE_PID);
+ current->pid = leader->pid;
+ attach_pid(current, PIDTYPE_PID, current->pid);
+ attach_pid(current, PIDTYPE_PGID, current->signal->pgrp);
+ attach_pid(current, PIDTYPE_SID, current->signal->session);
+ list_add_tail(&current->tasks, &init_task.tasks);
current->parent = current->real_parent = leader->real_parent;
leader->parent = leader->real_parent = child_reaper;
@@ -722,8 +732,6 @@ static int de_thread(struct task_struct *tsk)
__ptrace_link(current, parent);
}
- list_del(&current->tasks);
- list_add_tail(&current->tasks, &init_task.tasks);
current->exit_signal = SIGCHLD;
BUG_ON(leader->exit_state != EXIT_ZOMBIE);