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Commit 2ee08260 authored by Mike Rapoport's avatar Mike Rapoport Committed by Linus Torvalds
Browse files

pids: introduce find_get_task_by_vpid() helper 

There are several functions that do find_task_by_vpid() followed by
get_task_struct().  We can use a helper function instead.

Link: http://lkml.kernel.org/r/1509602027-11337-1-git-send-email-rppt@linux.vnet.ibm.com


Signed-off-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent eab216e9

arch/ia64/kernel/perfmon.c

+3 −10
Original line number Diff line number Diff line
@@ -2610,17 +2610,10 @@ pfm_get_task(pfm_context_t *ctx, pid_t pid, struct task_struct **task) 
	if (pid < 2) return -EPERM;



	if (pid != task_pid_vnr(current)) {



		read_lock(&tasklist_lock);



		p = find_task_by_vpid(pid);



		/* make sure task cannot go away while we operate on it */

		if (p) get_task_struct(p);



		read_unlock(&tasklist_lock);



		if (p == NULL) return -ESRCH;

		p = find_get_task_by_vpid(pid);

		if (!p)

			return -ESRCH;

	}



	ret = pfm_task_incompatible(ctx, p);

include/linux/sched.h

+5 −0
Original line number Diff line number Diff line
@@ -1489,6 +1489,11 @@ static inline struct thread_info *task_thread_info(struct task_struct *task) 
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);



/*

 * find a task by its virtual pid and get the task struct

 */

extern struct task_struct *find_get_task_by_vpid(pid_t nr);



extern int wake_up_state(struct task_struct *tsk, unsigned int state);

extern int wake_up_process(struct task_struct *tsk);

extern void wake_up_new_task(struct task_struct *tsk);

kernel/futex.c

+1 −19
Original line number Diff line number Diff line
@@ -862,24 +862,6 @@ static void put_pi_state(struct futex_pi_state *pi_state) 
	}

}



/*

 * Look up the task based on what TID userspace gave us.

 * We dont trust it.

 */

static struct task_struct *futex_find_get_task(pid_t pid)

{

	struct task_struct *p;



	rcu_read_lock();

	p = find_task_by_vpid(pid);

	if (p)

		get_task_struct(p);



	rcu_read_unlock();



	return p;

}



#ifdef CONFIG_FUTEX_PI



/*
@@ -1183,7 +1165,7 @@ static int attach_to_pi_owner(u32 uval, union futex_key *key, 
	 */

	if (!pid)

		return -ESRCH;

	p = futex_find_get_task(pid);

	p = find_get_task_by_vpid(pid);

	if (!p)

		return -ESRCH;

kernel/pid.c

+13 −0
Original line number Diff line number Diff line
@@ -343,6 +343,19 @@ struct task_struct *find_task_by_vpid(pid_t vnr) 
	return find_task_by_pid_ns(vnr, task_active_pid_ns(current));

}



struct task_struct *find_get_task_by_vpid(pid_t nr)

{

	struct task_struct *task;



	rcu_read_lock();

	task = find_task_by_vpid(nr);

	if (task)

		get_task_struct(task);

	rcu_read_unlock();



	return task;

}



struct pid *get_task_pid(struct task_struct *task, enum pid_type type)

{

	struct pid *pid;

kernel/ptrace.c

+6 −21
Original line number Diff line number Diff line
@@ -1103,21 +1103,6 @@ int ptrace_request(struct task_struct *child, long request, 
	return ret;

}



static struct task_struct *ptrace_get_task_struct(pid_t pid)

{

	struct task_struct *child;



	rcu_read_lock();

	child = find_task_by_vpid(pid);

	if (child)

		get_task_struct(child);

	rcu_read_unlock();



	if (!child)

		return ERR_PTR(-ESRCH);

	return child;

}



#ifndef arch_ptrace_attach

#define arch_ptrace_attach(child)	do { } while (0)

#endif
@@ -1135,9 +1120,9 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr, 
		goto out;

	}



	child = ptrace_get_task_struct(pid);

	if (IS_ERR(child)) {

		ret = PTR_ERR(child);

	child = find_get_task_by_vpid(pid);

	if (!child) {

		ret = -ESRCH;

		goto out;

	}
@@ -1281,9 +1266,9 @@ COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid, 
		goto out;

	}



	child = ptrace_get_task_struct(pid);

	if (IS_ERR(child)) {

		ret = PTR_ERR(child);

	child = find_get_task_by_vpid(pid);

	if (!child) {

		ret = -ESRCH;

		goto out;

	}