xen: use spin_lock_nest_lock when pinning a pagetable

When pinning/unpinning a pagetable with split pte locks, we can end up
holding multiple pte locks at once (we need to hold the locks while
there's a pending batched hypercall affecting the pte page).  Because
all the pte locks are in the same lock class, lockdep thinks that
we're potentially taking a lock recursively.

This warning is spurious because we always take the pte locks while
holding mm->page_table_lock.  lockdep now has spin_lock_nest_lock to
express this kind of dominant lock use, so use it here so that lockdep
knows what's going on.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 0 insertions, 3 deletions

diff --git a/arch/x86/xen/mmu.h b/arch/x86/xen/mmu.h
index 0f59bd03f9e3..98d71659da5a 100644
--- a/arch/x86/xen/mmu.h
+++ b/arch/x86/xen/mmu.h
@@ -18,9 +18,6 @@ void xen_activate_mm(struct mm_struct *prev, struct mm_struct *next);
 void xen_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm);
 void xen_exit_mmap(struct mm_struct *mm);
 
-void xen_pgd_pin(pgd_t *pgd);
-//void xen_pgd_unpin(pgd_t *pgd);
-
 pteval_t xen_pte_val(pte_t);
 pmdval_t xen_pmd_val(pmd_t);
 pgdval_t xen_pgd_val(pgd_t);