Changed task registration in SRP semaphores so that a pid is used rather

than a pointer to a task_struct. This eliminates the need to define the
task_struct struct in user space, and also makes the system call cleaner.
Required lookup of the task in the new system call.

1 files changed, 11 insertions, 2 deletions

diff --git a/arch/i386/kernel/srp_sem_syscalls.c b/arch/i386/kernel/srp_sem_syscalls.c
index 639f5821eb..24436a9bc8 100644
--- a/arch/i386/kernel/srp_sem_syscalls.c
+++ b/arch/i386/kernel/srp_sem_syscalls.c
@@ -113,14 +113,23 @@ asmlinkage long sys_srp_up(srp_sema_id sem_id)
  * ceiling! (The ceiling would be meaningless anyway, as the SRP
  * breaks without this a priori knowledge.)
  */
-asmlinkage long sys_reg_task_srp_sem(srp_sema_id sem_id,
-                                     struct task_struct *t)
+asmlinkage long sys_reg_task_srp_sem(srp_sema_id sem_id, pid_t t_pid)
 {
         unsigned long flags;
+        struct pid *task_pid;
+        struct task_struct *t;
 
         if (sem_id < 0 || sem_id >= MAX_SRP_SEMAPHORES)
                 return -EINVAL;
 
+        task_pid = find_get_pid(t_pid);
+        if (!task_pid)
+                return -EINVAL;
+
+        t = get_pid_task(task_pid, PIDTYPE_PID);
+        if (!t)
+                return -EINVAL;
+
         queue_lock_irqsave(&srp_lock, flags);
         if (srp_higher_prio(t, srp_sems[sem_id].pc_task))
                 srp_sems[sem_id].pc_task = t;