ptrace/x86: cleanup ptrace_set_debugreg()

ptrace_set_debugreg() is trivial but looks horrible.  Kill the unnecessary
goto's and return's to cleanup the code.

This matches ptrace_get_debugreg() which also needs the trivial whitespace
cleanups.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/kernel/ptrace.c

@@ -703,7 +703,7 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
  */
 static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
 {
-	struct thread_struct *thread = &(tsk->thread);
+	struct thread_struct *thread = &tsk->thread;
 	unsigned long val = 0;
 
 	if (n < HBP_NUM) {
@@ -761,30 +761,20 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
 static int ptrace_set_debugreg(struct task_struct *tsk, int n,
 			       unsigned long val)
 {
-	struct thread_struct *thread = &(tsk->thread);
-	int rc = 0;
-
+	struct thread_struct *thread = &tsk->thread;
 	/* There are no DR4 or DR5 registers */
-	if (n == 4 || n == 5)
-		return -EIO;
+	int rc = -EIO;
 
-	if (n == 6) {
-		thread->debugreg6 = val;
-		goto ret_path;
-	}
 	if (n < HBP_NUM) {
 		rc = ptrace_set_breakpoint_addr(tsk, n, val);
-		if (rc)
-			return rc;
-	}
-	/* All that's left is DR7 */
-	if (n == 7) {
+	} else if (n == 6) {
+		thread->debugreg6 = val;
+		rc = 0;
+	} else if (n == 7) {
 		rc = ptrace_write_dr7(tsk, val);
 		if (!rc)
 			thread->ptrace_dr7 = val;
 	}
-
-ret_path:
 	return rc;
 }