2 files changed, 19 insertions, 6 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
index e0beefb1..aeb115ef 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
@@ -985,12 +985,12 @@ unbind:
         ch->vpr = false;
         ch->vm = NULL;
 
-        mutex_lock(&ch->submit_lock);
+        mutex_lock(&ch->last_submit.fence_lock);
         gk20a_fence_put(ch->last_submit.pre_fence);
         gk20a_fence_put(ch->last_submit.post_fence);
         ch->last_submit.pre_fence = NULL;
         ch->last_submit.post_fence = NULL;
-        mutex_unlock(&ch->submit_lock);
+        mutex_unlock(&ch->last_submit.fence_lock);
         WARN_ON(ch->sync);
 
         /* unlink all debug sessions */
@@ -1424,12 +1424,12 @@ int gk20a_alloc_channel_gpfifo(struct channel_gk20a *c,
         ch_vm = c->vm;
 
         c->cmds_pending = false;
-        mutex_lock(&c->submit_lock);
+        mutex_lock(&c->last_submit.fence_lock);
         gk20a_fence_put(c->last_submit.pre_fence);
         gk20a_fence_put(c->last_submit.post_fence);
         c->last_submit.pre_fence = NULL;
         c->last_submit.post_fence = NULL;
-        mutex_unlock(&c->submit_lock);
+        mutex_unlock(&c->last_submit.fence_lock);
 
         c->ramfc.offset = 0;
         c->ramfc.size = ram_in_ramfc_s() / 8;
@@ -1958,11 +1958,13 @@ static void gk20a_channel_clean_up_jobs(struct work_struct *work)
          */
         if (list_empty(&c->jobs)) {
                 mutex_lock(&c->sync_lock);
+                mutex_lock(&c->last_submit.fence_lock);
                 if (c->sync && platform->aggressive_sync_destroy &&
                           gk20a_fence_is_expired(c->last_submit.post_fence)) {
                         c->sync->destroy(c->sync);
                         c->sync = NULL;
                 }
+                mutex_unlock(&c->last_submit.fence_lock);
                 mutex_unlock(&c->sync_lock);
         }
         mutex_unlock(&c->jobs_lock);
@@ -2270,12 +2272,14 @@ int gk20a_submit_channel_gpfifo(struct channel_gk20a *c,
                 incr_cmd->gp_put = c->gpfifo.put;
         }
 
+        mutex_lock(&c->last_submit.fence_lock);
         gk20a_fence_put(c->last_submit.pre_fence);
         gk20a_fence_put(c->last_submit.post_fence);
         c->last_submit.pre_fence = pre_fence;
         c->last_submit.post_fence = post_fence;
         if (fence_out)
                 *fence_out = gk20a_fence_get(post_fence);
+        mutex_unlock(&c->last_submit.fence_lock);
 
         /* TODO! Check for errors... */
         gk20a_channel_add_job(c, pre_fence, post_fence,
@@ -2325,6 +2329,7 @@ int gk20a_init_channel_support(struct gk20a *g, u32 chid)
         mutex_init(&c->ioctl_lock);
         mutex_init(&c->jobs_lock);
         mutex_init(&c->submit_lock);
+        mutex_init(&c->last_submit.fence_lock);
         mutex_init(&c->timeout.lock);
         mutex_init(&c->sync_lock);
         INIT_DELAYED_WORK(&c->timeout.wq, gk20a_channel_timeout_handler);
@@ -2347,11 +2352,19 @@ int gk20a_init_channel_support(struct gk20a *g, u32 chid)
 int gk20a_channel_finish(struct channel_gk20a *ch, unsigned long timeout)
 {
         int err = 0;
-        struct gk20a_fence *fence = ch->last_submit.post_fence;
+        struct gk20a_fence *fence;
 
         if (!ch->cmds_pending)
                 return 0;
 
+        mutex_lock(&ch->last_submit.fence_lock);
+        fence = ch->last_submit.post_fence;
+        if (!fence) {
+                mutex_unlock(&ch->last_submit.fence_lock);
+                return -EINVAL;
+        }
+        mutex_unlock(&ch->last_submit.fence_lock);
+
         /* Do not wait for a timedout channel */
         if (ch->has_timedout)
                 return -ETIMEDOUT;
diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.h b/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
index d8951b94..74c920e4 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.h
@@ -152,9 +152,9 @@ struct channel_gk20a {
 
         bool cmds_pending;
         struct {
-                /* These fences should be accessed with submit_lock held. */
                 struct gk20a_fence *pre_fence;
                 struct gk20a_fence *post_fence;
+                struct mutex fence_lock;
         } last_submit;
 
         void (*remove_support)(struct channel_gk20a *);