make gpu registration a little more robust

2 files changed, 8 insertions, 2 deletions

diff --git a/litmus/Kconfig b/litmus/Kconfig
index 263c3ee49c15..34ce6fb3a22e 100644
--- a/litmus/Kconfig
+++ b/litmus/Kconfig
@@ -298,7 +298,6 @@ config NR_LITMUS_SOFTIRQD
 
 config LITMUS_NVIDIA
           bool "Litmus handling of NVIDIA interrupts."
-          depends on LITMUS_SOFTIRQD || LITMUS_PAI_SOFTIRQD
           default n
           help
             Direct tasklets from NVIDIA devices to Litmus's klitirqd
diff --git a/litmus/nvidia_info.c b/litmus/nvidia_info.c
index 66181515186a..80900035881c 100644
--- a/litmus/nvidia_info.c
+++ b/litmus/nvidia_info.c
@@ -426,7 +426,12 @@ static int __reg_nv_device(int reg_device_id)
         struct task_struct *old_max = NULL;
         unsigned long flags;
         nv_device_registry_t *reg = &NV_DEVICE_REG[reg_device_id];
-        
+
+    if(__test_bit(reg_device_id, &tsk_rt(t)->held_gpus)) {
+                // TODO: check if taks is already registered.
+                return ret;  // assume already registered.
+        }
+                        
         raw_spin_lock_irqsave(&reg->lock, flags);
         
         if(reg->nr_owners < MAX_NR_OWNERS) {
@@ -478,6 +483,8 @@ static int __clear_reg_nv_device(int de_reg_device_id)
     struct task_struct* klitirqd_th = get_klitirqd(de_reg_device_id);
 #endif
         
+        WARN_ON(!__test_bit(de_reg_device_id, &tsk_rt(t)->held_gpus));
+
         raw_spin_lock_irqsave(&reg->lock, flags);
         
         for(i = 0; i < reg->nr_owners; ++i) {