[PATCH] bail out in mathemu if __copy_to_user fails

[Jesper Juhl <jesper.juhl@gmail.com>]

I believe we should check the return value of 
__copy_to_user in math-emu/fpu_entry.c and bail out of save_i387_soft() if 
it fails.
This patch does that.

This also kills the warning :
  arch/i386/math-emu/fpu_entry.c:745: warning: ignoring return value of `__copy_to_user', declared with attribute warn_unused_result


Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
---

diff --git a/arch/i386/math-emu/fpu_entry.c b/arch/i386/math-emu/fpu_entry.c
index d93f16e..ddf8fa3 100644
--- a/arch/i386/math-emu/fpu_entry.c
+++ b/arch/i386/math-emu/fpu_entry.c
@@ -742,7 +742,8 @@ #ifdef PECULIAR_486
   S387->fcs &= ~0xf8000000;
   S387->fos |= 0xffff0000;
 #endif /* PECULIAR_486 */
-  __copy_to_user(d, &S387->cwd, 7*4);
+  if (__copy_to_user(d, &S387->cwd, 7*4))
+    return -1;
   RE_ENTRANT_CHECK_ON;
 
   d += 7*4;