x86: ia32_setup_frame(): consolidate uaccess areas

Currently we have user_access block, followed by __put_user(),
deciding what the restorer will be and finally a put_user_try
block.

Moving the calculation of restorer first allows the rest
(actual copyout work) to coalesce into a single user_access block.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 799ca5b..7018c2c 100644 (file)
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -236,7 +236,6 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
 {
        struct sigframe_ia32 __user *frame;
        void __user *restorer;
-       int err = 0;
        void __user *fp = NULL;
 
        /* copy_to_user optimizes that into a single 8 byte store */
@@ -252,21 +251,6 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
 
        frame = get_sigframe(ksig, regs, sizeof(*frame), &fp);
 
-       if (!access_ok(frame, sizeof(*frame)))
-               return -EFAULT;
-
-       if (__put_user(sig, &frame->sig))
-               return -EFAULT;
-
-       if (!user_access_begin(&frame->sc, sizeof(struct sigcontext_32)))
-               return -EFAULT;
-
-       unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault);
-       user_access_end();
-
-       if (__put_user(set->sig[1], &frame->extramask[0]))
-               return -EFAULT;
-
        if (ksig->ka.sa.sa_flags & SA_RESTORER) {
                restorer = ksig->ka.sa.sa_restorer;
        } else {
@@ -278,19 +262,20 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
                        restorer = &frame->retcode;
        }
 
-       put_user_try {
-               put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
-
-               /*
-                * These are actually not used anymore, but left because some
-                * gdb versions depend on them as a marker.
-                */
-               put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode);
-       } put_user_catch(err);
-
-       if (err)
+       if (!user_access_begin(frame, sizeof(*frame)))
                return -EFAULT;
 
+       unsafe_put_user(sig, &frame->sig, Efault);
+       unsafe_put_sigcontext32(&frame->sc, fp, regs, set, Efault);
+       unsafe_put_user(set->sig[1], &frame->extramask[0], Efault);
+       unsafe_put_user(ptr_to_compat(restorer), &frame->pretcode, Efault);
+       /*
+        * These are actually not used anymore, but left because some
+        * gdb versions depend on them as a marker.
+        */
+       unsafe_put_user(*((u64 *)&code), (u64 __user *)frame->retcode, Efault);
+       user_access_end();
+
        /* Set up registers for signal handler */
        regs->sp = (unsigned long) frame;
        regs->ip = (unsigned long) ksig->ka.sa.sa_handler;