Revert the process group accessor functions. They are buggy, and

cause NULL pointer references in /proc.

Moreover, it's questionable whether the whole thing makes sense at all. 
Per-thread state is good.

Cset exclude: davem@nuts.ninka.net|ChangeSet|20031005193942|01097
Cset exclude: akpm@osdl.org[torvalds]|ChangeSet|20031005180420|42200
Cset exclude: akpm@osdl.org[torvalds]|ChangeSet|20031005180411|42211

6 files changed, 31 insertions, 38 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
index 37e98d713023..a679f4bb9854 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -343,7 +343,7 @@ static void do_acct_process(long exitcode, struct file *file)
 	/* we really need to bite the bullet and change layout */
 	ac.ac_uid = current->uid;
 	ac.ac_gid = current->gid;
-	ac.ac_tty = process_tty(current) ? old_encode_dev(tty_devnum(process_tty(current))) : 0;
+	ac.ac_tty = current->tty ? old_encode_dev(tty_devnum(current->tty)) : 0;
 
 	ac.ac_flag = 0;
 	if (current->flags & PF_FORKNOEXEC)
diff --git a/kernel/exit.c b/kernel/exit.c
index d7ed79d9a144..08e2068e2ae5 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -119,13 +119,13 @@ int session_of_pgrp(int pgrp)
 
 	read_lock(&tasklist_lock);
 	for_each_task_pid(pgrp, PIDTYPE_PGID, p, l, pid)
-		if (process_session(p) > 0) {
-			sid = process_session(p);
+		if (p->session > 0) {
+			sid = p->session;
 			goto out;
 		}
 	p = find_task_by_pid(pgrp);
 	if (p)
-		sid = process_session(p);
+		sid = p->session;
 out:
 	read_unlock(&tasklist_lock);
 	
@@ -153,7 +153,7 @@ static int will_become_orphaned_pgrp(int pgrp, task_t *ignored_task)
 				|| p->real_parent->pid == 1)
 			continue;
 		if (process_group(p->real_parent) != pgrp
-			    && process_session(p->real_parent) == process_session(p)) {
+			    && p->real_parent->session == p->session) {
 			ret = 0;
 			break;
 		}
@@ -242,14 +242,14 @@ void __set_special_pids(pid_t session, pid_t pgrp)
 {
 	struct task_struct *curr = current;
 
-	if (process_session(curr) != session) {
+	if (curr->session != session) {
 		detach_pid(curr, PIDTYPE_SID);
-		curr->signal->session = session;
+		curr->session = session;
 		attach_pid(curr, PIDTYPE_SID, session);
 	}
 	if (process_group(curr) != pgrp) {
 		detach_pid(curr, PIDTYPE_PGID);
-		curr->signal->pgrp = pgrp;
+		curr->group_leader->__pgrp = pgrp;
 		attach_pid(curr, PIDTYPE_PGID, pgrp);
 	}
 }
@@ -303,7 +303,7 @@ void daemonize(const char *name, ...)
 	exit_mm(current);
 
 	set_special_pids(1, 1);
-	current->signal->tty = NULL;
+	current->tty = NULL;
 
 	/* Block and flush all signals */
 	sigfillset(&blocked);
@@ -515,7 +515,7 @@ static inline void reparent_thread(task_t *p, task_t *father, int traced)
 	 * outside, so the child pgrp is now orphaned.
 	 */
 	if ((process_group(p) != process_group(father)) &&
-	    (process_session(p) == process_session(father))) {
+	    (p->session == father->session)) {
 		int pgrp = process_group(p);
 
 		if (will_become_orphaned_pgrp(pgrp, NULL) && has_stopped_jobs(pgrp)) {
@@ -625,7 +625,7 @@ static void exit_notify(struct task_struct *tsk)
 	t = tsk->real_parent;
 	
 	if ((process_group(t) != process_group(tsk)) &&
-	    (process_session(t) == process_session(tsk)) &&
+	    (t->session == tsk->session) &&
 	    will_become_orphaned_pgrp(process_group(tsk), tsk) &&
 	    has_stopped_jobs(process_group(tsk))) {
 		__kill_pg_info(SIGHUP, (void *)1, process_group(tsk));
@@ -720,7 +720,7 @@ NORET_TYPE void do_exit(long code)
 	exit_itimers(tsk);
 	exit_thread();
 
-	if (process_session_leader(tsk))
+	if (tsk->leader)
 		disassociate_ctty(1);
 
 	module_put(tsk->thread_info->exec_domain->module);
diff --git a/kernel/fork.c b/kernel/fork.c
index 0afba3e0e0ac..1834f99dd054 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -743,12 +743,6 @@ static inline int copy_signal(unsigned long clone_flags, struct task_struct * ts
 	sig->curr_target = NULL;
 	init_sigpending(&sig->shared_pending);
 
-	sig->tty = process_tty(current);
-	sig->pgrp = process_group(current);
-	sig->session = process_session(current);
-	sig->leader = 0;	/* session leadership doesn't inherit */
-	sig->tty_old_pgrp = 0;
-
 	return 0;
 }
 
@@ -795,9 +789,7 @@ struct task_struct *copy_process(unsigned long clone_flags,
 	 * Thread groups must share signals as well, and detached threads
 	 * can only be started up within the thread group.
 	 */
-	if ((clone_flags & CLONE_THREAD) &&
-		(clone_flags & (CLONE_SIGHAND|CLONE_DETACHED)) !=
-			(CLONE_SIGHAND|CLONE_DETACHED))
+	if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
 		return ERR_PTR(-EINVAL);
 
 	/*
@@ -902,6 +894,8 @@ struct task_struct *copy_process(unsigned long clone_flags,
 	init_timer(&p->real_timer);
 	p->real_timer.data = (unsigned long) p;
 
+	p->leader = 0;		/* session leadership doesn't inherit */
+	p->tty_old_pgrp = 0;
 	p->utime = p->stime = 0;
 	p->cutime = p->cstime = 0;
 	p->array = NULL;
@@ -1046,7 +1040,7 @@ struct task_struct *copy_process(unsigned long clone_flags,
 	if (thread_group_leader(p)) {
 		attach_pid(p, PIDTYPE_TGID, p->tgid);
 		attach_pid(p, PIDTYPE_PGID, process_group(p));
-		attach_pid(p, PIDTYPE_SID, process_session(p));
+		attach_pid(p, PIDTYPE_SID, p->session);
 		if (p->pid)
 			__get_cpu_var(process_counts)++;
 	} else
diff --git a/kernel/pid.c b/kernel/pid.c
index 624b54602fcb..4bb0bc0159d4 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -253,14 +253,14 @@ void switch_exec_pids(task_t *leader, task_t *thread)
 
 	attach_pid(thread, PIDTYPE_PID, thread->pid);
 	attach_pid(thread, PIDTYPE_TGID, thread->tgid);
-	attach_pid(thread, PIDTYPE_PGID, thread->signal->pgrp);
-	attach_pid(thread, PIDTYPE_SID, thread->signal->session);
+	attach_pid(thread, PIDTYPE_PGID, leader->__pgrp);
+	attach_pid(thread, PIDTYPE_SID, thread->session);
 	list_add_tail(&thread->tasks, &init_task.tasks);
 
 	attach_pid(leader, PIDTYPE_PID, leader->pid);
 	attach_pid(leader, PIDTYPE_TGID, leader->tgid);
-	attach_pid(leader, PIDTYPE_PGID, leader->signal->pgrp);
-	attach_pid(leader, PIDTYPE_SID, leader->signal->session);
+	attach_pid(leader, PIDTYPE_PGID, leader->__pgrp);
+	attach_pid(leader, PIDTYPE_SID, leader->session);
 }
 
 /*
diff --git a/kernel/signal.c b/kernel/signal.c
index 469deaeeff56..852da1a009da 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -593,8 +593,7 @@ static int check_kill_permission(int sig, struct siginfo *info,
 	error = -EPERM;
 	if ((!info || ((unsigned long)info != 1 &&
 			(unsigned long)info != 2 && SI_FROMUSER(info)))
-	    && ((sig != SIGCONT) ||
-		(process_session(current) != process_session(t)))
+	    && ((sig != SIGCONT) || (current->session != t->session))
 	    && (current->euid ^ t->suid) && (current->euid ^ t->uid)
 	    && (current->uid ^ t->suid) && (current->uid ^ t->uid)
 	    && !capable(CAP_KILL))
@@ -1103,7 +1102,7 @@ kill_sl_info(int sig, struct siginfo *info, pid_t sid)
 	retval = -ESRCH;
 	read_lock(&tasklist_lock);
 	for_each_task_pid(sid, PIDTYPE_SID, p, l, pid) {
-		if (!process_session_leader(p))
+		if (!p->leader)
 			continue;
 		err = group_send_sig_info(sig, info, p);
 		if (retval)
diff --git a/kernel/sys.c b/kernel/sys.c
index 7413a1067472..9b914004fde8 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -969,7 +969,7 @@ asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
 
 	if (p->parent == current || p->real_parent == current) {
 		err = -EPERM;
-		if (process_session(p) != process_session(current))
+		if (p->session != current->session)
 			goto out;
 		err = -EACCES;
 		if (p->did_exec)
@@ -981,7 +981,7 @@ asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
 	}
 
 	err = -EPERM;
-	if (process_session_leader(p))
+	if (p->leader)
 		goto out;
 
 	if (pgid != pid) {
@@ -990,7 +990,7 @@ asmlinkage long sys_setpgid(pid_t pid, pid_t pgid)
 		struct list_head *l;
 
 		for_each_task_pid(pgid, PIDTYPE_PGID, p, l, pid)
-			if (process_session(p) == process_session(current))
+			if (p->session == current->session)
 				goto ok_pgid;
 		goto out;
 	}
@@ -1002,7 +1002,7 @@ ok_pgid:
 
 	if (process_group(p) != pgid) {
 		detach_pid(p, PIDTYPE_PGID);
-		p->signal->pgrp = pgid;
+		p->group_leader->__pgrp = pgid;
 		attach_pid(p, PIDTYPE_PGID, pgid);
 	}
 
@@ -1044,7 +1044,7 @@ asmlinkage long sys_getpgrp(void)
 asmlinkage long sys_getsid(pid_t pid)
 {
 	if (!pid) {
-		return process_session(current);
+		return current->session;
 	} else {
 		int retval;
 		struct task_struct *p;
@@ -1056,7 +1056,7 @@ asmlinkage long sys_getsid(pid_t pid)
 		if(p) {
 			retval = security_task_getsid(p);
 			if (!retval)
-				retval = process_session(p);
+				retval = p->session;
 		}
 		read_unlock(&tasklist_lock);
 		return retval;
@@ -1077,10 +1077,10 @@ asmlinkage long sys_setsid(void)
 	if (pid)
 		goto out;
 
-	current->signal->leader = 1;
+	current->leader = 1;
 	__set_special_pids(current->pid, current->pid);
-	current->signal->tty = NULL;
-	current->signal->tty_old_pgrp = 0;
+	current->tty = NULL;
+	current->tty_old_pgrp = 0;
 	err = process_group(current);
 out:
 	write_unlock_irq(&tasklist_lock);