From 2d8b22de6e5241a6f27f7f290f027223156a7d3f Mon Sep 17 00:00:00 2001 From: John David Anglin Date: Sat, 5 Oct 2013 10:55:36 -0400 Subject: [PATCH] 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 Signed-off-by: Helge Deller --- arch/parisc/mm/fault.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c index 00c0ed333a3d..0293588d5b8c 100644 --- 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: -- 2.30.2