parisc: optimize variable initialization in do_page_fault

The attached change defers the initialization of the variables tsk, mm
and flags until they are needed. As a result, the code won't crash if a
kernel probe is done with a corrupt context and the code will be better
optimized.

Signed-off-by: John David Anglin  <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index 00c0ed3..0293588 100644 (file)
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -171,20 +171,25 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
                              unsigned long address)
 {
        struct vm_area_struct *vma, *prev_vma;
-       struct task_struct *tsk = current;
-       struct mm_struct *mm = tsk->mm;
+       struct task_struct *tsk;
+       struct mm_struct *mm;
        unsigned long acc_type;
        int fault;
-       unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+       unsigned int flags;
 
-       if (in_atomic() || !mm)
+       if (in_atomic())
                goto no_context;
 
+       tsk = current;
+       mm = tsk->mm;
+       if (!mm)
+               goto no_context;
+
+       flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
        if (user_mode(regs))
                flags |= FAULT_FLAG_USER;
 
        acc_type = parisc_acctyp(code, regs->iir);
-
        if (acc_type & VM_WRITE)
                flags |= FAULT_FLAG_WRITE;
 retry: