Merge branch 'master'

[linux-2.6-omap-h63xx.git] / include / asm-sparc64 / mmu_context.h

diff --git a/include/asm-sparc64/mmu_context.h b/include/asm-sparc64/mmu_context.h
index 87c43c67866e9bb6afbc5cdd8186d3edecdf5816..08ba72d7722c9c4be4fe7d96eb534ceb75d968c4 100644 (file)
--- a/include/asm-sparc64/mmu_context.h
+++ b/include/asm-sparc64/mmu_context.h
@@ -87,37 +87,35 @@ extern void __flush_tlb_mm(unsigned long, unsigned long);
 static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk)
 {
        unsigned long ctx_valid;
+       int cpu;
 
+       /* Note: page_table_lock is used here to serialize switch_mm
+        * and activate_mm, and their calls to get_new_mmu_context.
+        * This use of page_table_lock is unrelated to its other uses.
+        */ 
        spin_lock(&mm->page_table_lock);
-       if (CTX_VALID(mm->context))
-               ctx_valid = 1;
-        else
-               ctx_valid = 0;
+       ctx_valid = CTX_VALID(mm->context);
+       if (!ctx_valid)
+               get_new_mmu_context(mm);
+       spin_unlock(&mm->page_table_lock);
 
        if (!ctx_valid || (old_mm != mm)) {
-               if (!ctx_valid)
-                       get_new_mmu_context(mm);
-
                load_secondary_context(mm);
                reload_tlbmiss_state(tsk, mm);
        }
 
-       {
-               int cpu = smp_processor_id();
-
-               /* Even if (mm == old_mm) we _must_ check
-                * the cpu_vm_mask.  If we do not we could
-                * corrupt the TLB state because of how
-                * smp_flush_tlb_{page,range,mm} on sparc64
-                * and lazy tlb switches work. -DaveM
-                */
-               if (!ctx_valid || !cpu_isset(cpu, mm->cpu_vm_mask)) {
-                       cpu_set(cpu, mm->cpu_vm_mask);
-                       __flush_tlb_mm(CTX_HWBITS(mm->context),
-                                      SECONDARY_CONTEXT);
-               }
+       /* Even if (mm == old_mm) we _must_ check
+        * the cpu_vm_mask.  If we do not we could
+        * corrupt the TLB state because of how
+        * smp_flush_tlb_{page,range,mm} on sparc64
+        * and lazy tlb switches work. -DaveM
+        */
+       cpu = smp_processor_id();
+       if (!ctx_valid || !cpu_isset(cpu, mm->cpu_vm_mask)) {
+               cpu_set(cpu, mm->cpu_vm_mask);
+               __flush_tlb_mm(CTX_HWBITS(mm->context),
+                              SECONDARY_CONTEXT);
        }
-       spin_unlock(&mm->page_table_lock);
 }
 
 #define deactivate_mm(tsk,mm)  do { } while (0)
@@ -127,6 +125,10 @@ static inline void activate_mm(struct mm_struct *active_mm, struct mm_struct *mm
 {
        int cpu;
 
+       /* Note: page_table_lock is used here to serialize switch_mm
+        * and activate_mm, and their calls to get_new_mmu_context.
+        * This use of page_table_lock is unrelated to its other uses.
+        */ 
        spin_lock(&mm->page_table_lock);
        if (!CTX_VALID(mm->context))
                get_new_mmu_context(mm);