[SPARC64]: Bulletproof MMU context locking.

1) Always spin_lock_init() in init_context().  The caller essentially
   clears it out, or copies the mm info from the parent.  In both
   cases we need to explicitly initialize the spinlock.

2) Always do explicit IRQ disabling while taking mm->context.lock
   and ctx_alloc_lock.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/include/asm-sparc64/mmu_context.h b/include/asm-sparc64/mmu_context.h
index 4be40c58e3c1..ca36ea96f64b 100644
--- a/include/asm-sparc64/mmu_context.h
+++ b/include/asm-sparc64/mmu_context.h
@@ -67,14 +67,14 @@ extern void __flush_tlb_mm(unsigned long, unsigned long);
 /* Switch the current MM context.  Interrupts are disabled.  */
 static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk)
 {
-        unsigned long ctx_valid;
+        unsigned long ctx_valid, flags;
         int cpu;
 
-        spin_lock(&mm->context.lock);
+        spin_lock_irqsave(&mm->context.lock, flags);
         ctx_valid = CTX_VALID(mm->context);
         if (!ctx_valid)
                 get_new_mmu_context(mm);
-        spin_unlock(&mm->context.lock);
+        spin_unlock_irqrestore(&mm->context.lock, flags);
 
         if (!ctx_valid || (old_mm != mm)) {
                 load_secondary_context(mm);