CRIS v32: Avoid work when switching between tasks with shared memory descriptors in mm/tlb.c

There is no need to do all this work if they share memory descriptors.
Also, fix some minor whitespace and long lines.

1 files changed, 28 insertions, 28 deletions

diff --git a/arch/cris/arch-v32/mm/tlb.c b/arch/cris/arch-v32/mm/tlb.c
index a076ef6e9389..eda5ebcaea54 100644
--- a/arch/cris/arch-v32/mm/tlb.c
+++ b/arch/cris/arch-v32/mm/tlb.c
@@ -13,8 +13,8 @@
 #include <asm/arch/hwregs/supp_reg.h>
 
 #define UPDATE_TLB_SEL_IDX(val)                                 \
-do {                                                            \
-        unsigned long tlb_sel;                                  \
+do {                                                            \
+        unsigned long tlb_sel;                                  \
                                                                 \
         tlb_sel = REG_FIELD(mmu, rw_mm_tlb_sel, idx, val);      \
         SUPP_REG_WR(RW_MM_TLB_SEL, tlb_sel);                    \
@@ -30,8 +30,8 @@ do {						\
  * The TLB can host up to 256 different mm contexts at the same time. The running
  * context is found in the PID register. Each TLB entry contains a page_id that
  * has to match the PID register to give a hit. page_id_map keeps track of which
- * mm is assigned to which page_id, making sure it's known when to invalidate TLB
- * entries.
+ * mm's is assigned to which page_id's, making sure it's known when to
+ * invalidate TLB entries.
  *
  * The last page_id is never running, it is used as an invalid page_id so that
  * it's possible to make TLB entries that will nerver match.
@@ -179,29 +179,29 @@ void
 switch_mm(struct mm_struct *prev, struct mm_struct *next,
           struct task_struct *tsk)
 {
-        int cpu = smp_processor_id();
-
-        /* Make sure there is a MMU context. */
-        spin_lock(&mmu_context_lock);
-        get_mmu_context(next);
-        cpu_set(cpu, next->cpu_vm_mask);
-        spin_unlock(&mmu_context_lock);
-
-        /*
-         * Remember the pgd for the fault handlers. Keep a separate copy of it
-         * because current and active_mm might be invalid at points where
-         * there's still a need to derefer the pgd.
-         */
-        per_cpu(current_pgd, cpu) = next->pgd;
-
-        /* Switch context in the MMU. */
-        if (tsk && task_thread_info(tsk))
-        {
-          SPEC_REG_WR(SPEC_REG_PID, next->context.page_id | task_thread_info(tsk)->tls);
-        }
-        else
-        {
-          SPEC_REG_WR(SPEC_REG_PID, next->context.page_id);
-        }
+        if (prev != next) {
+                int cpu = smp_processor_id();
+
+                /* Make sure there is a MMU context. */
+                spin_lock(&mmu_context_lock);
+                get_mmu_context(next);
+                cpu_set(cpu, next->cpu_vm_mask);
+                spin_unlock(&mmu_context_lock);
+
+                /*
+                 * Remember the pgd for the fault handlers. Keep a seperate
+                 * copy of it because current and active_mm might be invalid
+                 * at points where * there's still a need to derefer the pgd.
+                 */
+                per_cpu(current_pgd, cpu) = next->pgd;
+
+                /* Switch context in the MMU. */
+                if (tsk && task_thread_info(tsk)) {
+                        SPEC_REG_WR(SPEC_REG_PID, next->context.page_id |
+                                task_thread_info(tsk)->tls);
+                } else {
+                        SPEC_REG_WR(SPEC_REG_PID, next->context.page_id);
+                }
+        }
 }