[PATCH 1/2] Uninline find_task_by_xxx set of functions

[PATCH 1/2] Uninline find_task_by_xxx set of functions

[Pavel Emelyanov]

The find_task_by_something is a set of macros are used to find
task by pid depending on what kind of pid is proposed - global
or virtual one. All of them are wrappers above the most generic
one - find_task_by_pid_type_ns() - and just substitute some 
args for it.

It turned out, that dereferencing the current->nsproxy->pid_ns 
construction and pushing one more argument on the stack inline
cause kernel text size to grow.

This patch moves all this stuff out-of-line into kernel/pid.c. 
Together with the next patch it saves a bit less than 400 bytes 
from the .text section.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

---

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 12ef317..8c0e146 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1495,9 +1495,8 @@ extern struct pid_namespace init_pid_ns;
  *      type and namespace specified
  * find_task_by_pid_ns():
  *      finds a task by its pid in the specified namespace
- * find_task_by_pid_type():
- *      finds a task by its global id with the specified type, e.g.
- *      by global session id
+ * find_task_by_vpid():
+ *      finds a task by its virtual pid
  * find_task_by_pid():
  *      finds a task by its global pid
  *
@@ -1507,12 +1506,10 @@ extern struct pid_namespace init_pid_ns;
 extern struct task_struct *find_task_by_pid_type_ns(int type, int pid,
 		struct pid_namespace *ns);
 
-#define find_task_by_pid_ns(nr, ns)	\
-		find_task_by_pid_type_ns(PIDTYPE_PID, nr, ns)
-#define find_task_by_pid_type(type, nr)	\
-		find_task_by_pid_type_ns(type, nr, &init_pid_ns)
-#define find_task_by_pid(nr)		\
-		find_task_by_pid_type(PIDTYPE_PID, nr)
+extern struct task_struct *find_task_by_pid(pid_t nr);
+extern struct task_struct *find_task_by_vpid(pid_t nr);
+extern struct task_struct *find_task_by_pid_ns(pid_t nr,
+		struct pid_namespace *ns);
 
 extern void __set_special_pids(pid_t session, pid_t pgrp);
 
diff --git a/kernel/pid.c b/kernel/pid.c
index e2e060e..f029c17 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -368,6 +380,25 @@ struct task_struct *find_task_by_pid_typ
 
 EXPORT_SYMBOL(find_task_by_pid_type_ns);
 
+struct task_struct *find_task_by_pid(pid_t nr)
+{
+	return find_task_by_pid_type_ns(PIDTYPE_PID, nr, &init_pid_ns);
+}
+EXPORT_SYMBOL(find_task_by_pid);
+
+struct task_struct *find_task_by_vpid(pid_t vnr)
+{
+	return find_task_by_pid_type_ns(PIDTYPE_PID, vnr,
+			current->nsproxy->pid_ns);
+}
+EXPORT_SYMBOL(find_task_by_vpid);
+
+struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns)
+{
+	return find_task_by_pid_type_ns(PIDTYPE_PID, nr, ns);
+}
+EXPORT_SYMBOL(find_task_by_pid_ns);
+
 struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
 {
 	struct pid *pid;
diff --git a/fs/ioprio.c b/fs/ioprio.c
index 0a615f8..d6ff77e 100644
--- a/fs/ioprio.c
+++ b/fs/ioprio.c
@@ -94,8 +94,7 @@ asmlinkage long sys_ioprio_set(int which
 			if (!who)
 				p = current;
 			else
-				p = find_task_by_pid_ns(who,
-						current->nsproxy->pid_ns);
+				p = find_task_by_vpid(who);
 			if (p)
 				ret = set_task_ioprio(p, ioprio);
 			break;
@@ -182,8 +181,7 @@ asmlinkage long sys_ioprio_get(int which
 			if (!who)
 				p = current;
 			else
-				p = find_task_by_pid_ns(who,
-						current->nsproxy->pid_ns);
+				p = find_task_by_vpid(who);
 			if (p)
 				ret = get_task_ioprio(p);
 			break;
diff --git a/kernel/capability.c b/kernel/capability.c
index 0440d6d..4a881b8 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -63,8 +63,7 @@ asmlinkage long sys_capget(cap_user_head
 	read_lock(&tasklist_lock);
 
 	if (pid && pid != task_pid_vnr(current)) {
-		target = find_task_by_pid_ns(pid,
-				current->nsproxy->pid_ns);
+		target = find_task_by_vpid(pid);
 		if (!target) {
 			ret = -ESRCH;
 			goto out;
@@ -198,8 +197,7 @@ asmlinkage long sys_capset(cap_user_head
 	read_lock(&tasklist_lock);
 
 	if (pid > 0 && pid != task_pid_vnr(current)) {
-		target = find_task_by_pid_ns(pid,
-				current->nsproxy->pid_ns);
+		target = find_task_by_vpid(pid);
 		if (!target) {
 			ret = -ESRCH;
 			goto out;
diff --git a/kernel/futex.c b/kernel/futex.c
index 0c1b777..0d51412 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -444,9 +444,7 @@ static struct task_struct * futex_find_g
 	struct task_struct *p;
 
 	rcu_read_lock();
-	p = find_task_by_pid_ns(pid,
-			current->nsproxy->pid_ns);
-
+	p = find_task_by_vpid(pid);
 	if (!p || ((current->euid != p->euid) && (current->euid != p->uid)))
 		p = ERR_PTR(-ESRCH);
 	else
@@ -1856,8 +1854,7 @@ sys_get_robust_list(int pid, struct robu
 
 		ret = -ESRCH;
 		rcu_read_lock();
-		p = find_task_by_pid_ns(pid,
-				current->nsproxy->pid_ns);
+		p = find_task_by_vpid(pid);
 		if (!p)
 			goto err_unlock;
 		ret = -EPERM;
diff --git a/kernel/futex_compat.c b/kernel/futex_compat.c
index a21e766..d64f7c3 100644
--- a/kernel/futex_compat.c
+++ b/kernel/futex_compat.c
@@ -118,8 +118,7 @@ compat_sys_get_robust_list(int pid, comp
 
 		ret = -ESRCH;
 		read_lock(&tasklist_lock);
-		p = find_task_by_pid_ns(pid,
-				current->nsproxy->pid_ns);
+		p = find_task_by_vpid(pid);
 		if (!p)
 			goto err_unlock;
 		ret = -EPERM;
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 812f1f3..593afeb 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -444,8 +444,7 @@ struct task_struct *ptrace_get_task_stru
 		return ERR_PTR(-EPERM);
 
 	read_lock(&tasklist_lock);
-	child = find_task_by_pid_ns(pid,
-			current->nsproxy->pid_ns);
+	child = find_task_by_vpid(pid);
 	if (child)
 		get_task_struct(child);
 
diff --git a/kernel/sched.c b/kernel/sched.c
index 80f5695..ec03e40 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4156,8 +4156,7 @@ struct task_struct *idle_task(int cpu)
  */
 static inline struct task_struct *find_process_by_pid(pid_t pid)
 {
-	return pid ?
-		find_task_by_pid_ns(pid, current->nsproxy->pid_ns) : current;
+	return pid ? find_task_by_vpid(pid) : current;
 }
 
 /* Actually do priority change: must hold rq lock. */
diff --git a/kernel/signal.c b/kernel/signal.c
index c5d72be..c308c2d 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2237,7 +2237,7 @@ static int do_tkill(int tgid, int pid, i
 	info.si_uid = current->uid;
 
 	read_lock(&tasklist_lock);
-	p = find_task_by_pid_ns(pid, current->nsproxy->pid_ns);
+	p = find_task_by_vpid(pid);
 	if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
 		error = check_kill_permission(sig, &info, p);
 		/*
diff --git a/kernel/sys.c b/kernel/sys.c
index 787b73e..796299c 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -151,8 +151,7 @@ asmlinkage long sys_setpriority(int whic
 	switch (which) {
 		case PRIO_PROCESS:
 			if (who)
-				p = find_task_by_pid_ns(who,
-						current->nsproxy->pid_ns);
+				p = find_task_by_vpid(who);
 			else
 				p = current;
 			if (p)
@@ -209,8 +208,7 @@ asmlinkage long sys_getpriority(int whic
 	switch (which) {
 		case PRIO_PROCESS:
 			if (who)
-				p = find_task_by_pid_ns(who,
-						current->nsproxy->pid_ns);
+				p = find_task_by_vpid(who);
 			else
 				p = current;
 			if (p) {
@@ -1065,7 +1063,8 @@ asmlinkage long sys_setsid(void)
 	 * session id and so the check will always fail and make it so
 	 * init cannot successfully call setsid.
 	 */
-	if (session > 1 && find_task_by_pid_type(PIDTYPE_PGID, session))
+	if (session > 1 && find_task_by_pid_type_ns(PIDTYPE_PGID,
+				session, &init_pid_ns))
 		goto out;
 
 	group_leader->signal->leader = 1;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index a09ca3b..c1592a9 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -941,8 +941,7 @@ asmlinkage long sys_migrate_pages(pid_t 
 
 	/* Find the mm_struct */
 	read_lock(&tasklist_lock);
-	task = pid ?
-		find_task_by_pid_ns(pid, current->nsproxy->pid_ns) : current;
+	task = pid ? find_task_by_vpid(pid) : current;
 	if (!task) {
 		read_unlock(&tasklist_lock);
 		return -ESRCH;
diff --git a/mm/migrate.c b/mm/migrate.c
index 6f7e4f3..7fff95d 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -931,8 +931,7 @@ asmlinkage long sys_move_pages(pid_t pid
 
 	/* Find the mm_struct */
 	read_lock(&tasklist_lock);
-	task = pid ?
-		find_task_by_pid_ns(pid, current->nsproxy->pid_ns) : current;
+	task = pid ? find_task_by_vpid(pid) : current;
 	if (!task) {
 		read_unlock(&tasklist_lock);
 		return -ESRCH;