x86/paravirt: allow preemption with lazy mmu mode

Impact: remove obsolete checks, simplification

Lift restrictions on preemption with lazy mmu mode, as it is now allowed.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

1 files changed, 1 insertions, 7 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index f5f8faa4f76c..3f2d0fe5e6a8 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -419,10 +419,6 @@ void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags)
 void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
                     pte_t *ptep, pte_t pteval)
 {
-        /* updates to init_mm may be done without lock */
-        if (mm == &init_mm)
-                preempt_disable();
-
         ADD_STATS(set_pte_at, 1);
 //      ADD_STATS(set_pte_at_pinned, xen_page_pinned(ptep));
         ADD_STATS(set_pte_at_current, mm == current->mm);
@@ -443,9 +439,7 @@ void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,
         }
         xen_set_pte(ptep, pteval);
 
-out:
-        if (mm == &init_mm)
-                preempt_enable();
+out:    return;
 }
 
 pte_t xen_ptep_modify_prot_start(struct mm_struct *mm,