[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, 29 deletions

diff --git a/arch/sparc/kernel/ptrace.c b/arch/sparc/kernel/ptrace.c
index 475c4c13462c..fc470c0e9dc6 100644
--- a/arch/sparc/kernel/ptrace.c
+++ b/arch/sparc/kernel/ptrace.c
@@ -286,40 +286,17 @@ asmlinkage void do_ptrace(struct pt_regs *regs)
                                s, (int) request, (int) pid, addr, data, addr2);
         }
 #endif
-        if (request == PTRACE_TRACEME) {
-                int my_ret;
-
-                /* are we already being traced? */
-                if (current->ptrace & PT_PTRACED) {
-                        pt_error_return(regs, EPERM);
-                        goto out;
-                }
-                my_ret = security_ptrace(current->parent, current);
-                if (my_ret) {
-                        pt_error_return(regs, -my_ret);
-                        goto out;
-                }
 
-                /* set the ptrace bit in the process flags. */
-                current->ptrace |= PT_PTRACED;
+        if (request == PTRACE_TRACEME) {
+                ret = ptrace_traceme();
                 pt_succ_return(regs, 0);
                 goto out;
         }
-#ifndef ALLOW_INIT_TRACING
-        if (pid == 1) {
-                /* Can't dork with init. */
-                pt_error_return(regs, EPERM);
-                goto out;
-        }
-#endif
-        read_lock(&tasklist_lock);
-        child = find_task_by_pid(pid);
-        if (child)
-                get_task_struct(child);
-        read_unlock(&tasklist_lock);
 
-        if (!child) {
-                pt_error_return(regs, ESRCH);
+        child = ptrace_get_task_struct(pid);
+        if (IS_ERR(child)) {
+                ret = PTR_ERR(child);
+                pt_error_return(regs, -ret);
                 goto out;
         }