[PATCH] usb: fixup usb so it uses struct pid

The problem with remembering a user space process by its pid is that it is
possible that the process will exit, pid wrap around will occur.
Converting to a struct pid avoid that problem, and paves the way for
implementing a pid namespace.

Also since usb is the only user of kill_proc_info_as_uid rename
kill_proc_info_as_uid to kill_pid_info_as_uid and have the new version take
a struct pid.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

5 files changed, 13 insertions, 11 deletions

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index a94c63bef632..3f509beb88e4 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -65,7 +65,7 @@ DEFINE_MUTEX(usbfs_mutex);
 struct async {
         struct list_head asynclist;
         struct dev_state *ps;
-        pid_t pid;
+        struct pid *pid;
         uid_t uid, euid;
         unsigned int signr;
         unsigned int ifnum;
@@ -225,6 +225,7 @@ static struct async *alloc_async(unsigned int numisoframes)
 
 static void free_async(struct async *as)
 {
+        put_pid(as->pid);
         kfree(as->urb->transfer_buffer);
         kfree(as->urb->setup_packet);
         usb_free_urb(as->urb);
@@ -317,7 +318,7 @@ static void async_completed(struct urb *urb, struct pt_regs *regs)
                 sinfo.si_errno = as->urb->status;
                 sinfo.si_code = SI_ASYNCIO;
                 sinfo.si_addr = as->userurb;
-                kill_proc_info_as_uid(as->signr, &sinfo, as->pid, as->uid, 
+                kill_pid_info_as_uid(as->signr, &sinfo, as->pid, as->uid,
                                       as->euid, as->secid);
         }
         snoop(&urb->dev->dev, "urb complete\n");
@@ -573,7 +574,7 @@ static int usbdev_open(struct inode *inode, struct file *file)
         INIT_LIST_HEAD(&ps->async_completed);
         init_waitqueue_head(&ps->wait);
         ps->discsignr = 0;
-        ps->disc_pid = current->pid;
+        ps->disc_pid = get_pid(task_pid(current));
         ps->disc_uid = current->uid;
         ps->disc_euid = current->euid;
         ps->disccontext = NULL;
@@ -611,6 +612,7 @@ static int usbdev_release(struct inode *inode, struct file *file)
         usb_autosuspend_device(dev, 1);
         usb_unlock_device(dev);
         usb_put_dev(dev);
+        put_pid(ps->disc_pid);
         kfree(ps);
         return 0;
 }
@@ -1063,7 +1065,7 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb,
                 as->userbuffer = NULL;
         as->signr = uurb->signr;
         as->ifnum = ifnum;
-        as->pid = current->pid;
+        as->pid = get_pid(task_pid(current));
         as->uid = current->uid;
         as->euid = current->euid;
         security_task_getsecid(current, &as->secid);
diff --git a/drivers/usb/core/inode.c b/drivers/usb/core/inode.c
index 7c77c2d8d300..b5d6a79af0be 100644
--- a/drivers/usb/core/inode.c
+++ b/drivers/usb/core/inode.c
@@ -699,7 +699,7 @@ static void usbfs_remove_device(struct usb_device *dev)
                         sinfo.si_errno = EPIPE;
                         sinfo.si_code = SI_ASYNCIO;
                         sinfo.si_addr = ds->disccontext;
-                        kill_proc_info_as_uid(ds->discsignr, &sinfo, ds->disc_pid, ds->disc_uid, ds->disc_euid, ds->secid);
+                        kill_pid_info_as_uid(ds->discsignr, &sinfo, ds->disc_pid, ds->disc_uid, ds->disc_euid, ds->secid);
                 }
         }
 }
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index f69df137ec0e..13322e33f912 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -139,7 +139,7 @@ struct dev_state {
         struct list_head async_completed;
         wait_queue_head_t wait;     /* wake up if a request completed */
         unsigned int discsignr;
-        pid_t disc_pid;
+        struct pid *disc_pid;
         uid_t disc_uid, disc_euid;
         void __user *disccontext;
         unsigned long ifclaimed;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 3b7c99265ace..a7fff3304bd6 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1269,12 +1269,12 @@ extern int force_sig_info(int, struct siginfo *, struct task_struct *);
 extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
 extern int kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
 extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
+extern int kill_pid_info_as_uid(int, struct siginfo *, struct pid *, uid_t, uid_t, u32);
 extern int kill_pgrp(struct pid *pid, int sig, int priv);
 extern int kill_pid(struct pid *pid, int sig, int priv);
 extern int __kill_pg_info(int sig, struct siginfo *info, pid_t pgrp);
 extern int kill_pg_info(int, struct siginfo *, pid_t);
 extern int kill_proc_info(int, struct siginfo *, pid_t);
-extern int kill_proc_info_as_uid(int, struct siginfo *, pid_t, uid_t, uid_t, u32);
 extern void do_notify_parent(struct task_struct *, int);
 extern void force_sig(int, struct task_struct *);
 extern void force_sig_specific(int, struct task_struct *);
diff --git a/kernel/signal.c b/kernel/signal.c
index 5230ddcb1757..7ed8d5304bec 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1136,8 +1136,8 @@ kill_proc_info(int sig, struct siginfo *info, pid_t pid)
         return error;
 }
 
-/* like kill_proc_info(), but doesn't use uid/euid of "current" */
-int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid,
+/* like kill_pid_info(), but doesn't use uid/euid of "current" */
+int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
                       uid_t uid, uid_t euid, u32 secid)
 {
         int ret = -EINVAL;
@@ -1147,7 +1147,7 @@ int kill_proc_info_as_uid(int sig, struct siginfo *info, pid_t pid,
                 return ret;
 
         read_lock(&tasklist_lock);
-        p = find_task_by_pid(pid);
+        p = pid_task(pid, PIDTYPE_PID);
         if (!p) {
                 ret = -ESRCH;
                 goto out_unlock;
@@ -1171,7 +1171,7 @@ out_unlock:
         read_unlock(&tasklist_lock);
         return ret;
 }
-EXPORT_SYMBOL_GPL(kill_proc_info_as_uid);
+EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
 
 /*
  * kill_something_info() interprets pid in interesting ways just like kill(2).