[PATCH] use ptrace_get_task_struct in various places

The ptrace_get_task_struct() helper that I added as part of the ptrace
consolidation is useful in variety of places that currently opencode it.
Switch them to the common helpers.

Add a ptrace_traceme() helper that needs to be explicitly called, and simplify
the ptrace_get_task_struct() interface.  We don't need the request argument
now, and we return the task_struct directly, using ERR_PTR() for error
returns.  It's a bit more code in the callers, but we have two sane routines
that do one thing well now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 23 deletions

diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 8ecda6d66de4..cc02232aa96e 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -712,35 +712,18 @@ sys_ptrace(long request, long pid, long addr, long data)
         int ret;
 
         lock_kernel();
-
         if (request == PTRACE_TRACEME) {
-                /* are we already being traced? */
-                ret = -EPERM;
-                if (current->ptrace & PT_PTRACED)
-                        goto out;
-                ret = security_ptrace(current->parent, current);
-                if (ret)
-                        goto out;
-                /* set the ptrace bit in the process flags. */
-                current->ptrace |= PT_PTRACED;
-                goto out;
+                 ret = ptrace_traceme();
+                 goto out;
         }
 
-        ret = -EPERM;
-        if (pid == 1)           /* you may not mess with init */
-                goto out;
-
-        ret = -ESRCH;
-        read_lock(&tasklist_lock);
-        child = find_task_by_pid(pid);
-        if (child)
-                get_task_struct(child);
-        read_unlock(&tasklist_lock);
-        if (!child)
+        child = ptrace_get_task_struct(pid);
+        if (IS_ERR(child)) {
+                ret = PTR_ERR(child);
                 goto out;
+        }
 
         ret = do_ptrace(child, request, addr, data);
-
         put_task_struct(child);
 out:
         unlock_kernel();