2 files changed, 22 insertions, 3 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
index 56ff4c87..6383b8c8 100644
--- a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
@@ -1779,7 +1779,7 @@ static int gk20a_fifo_update_runlist_locked(struct gk20a *g, u32 runlist_id,
                         if (test_and_set_bit(hw_chid,
                                 runlist->active_channels) == 1)
                                 return 0;
-                        if (tsg && ++tsg->num_active_channels > 0)
+                        if (tsg && ++tsg->num_active_channels)
                                 set_bit(f->channel[hw_chid].tsgid,
                                         runlist->active_tsgs);
                 } else {
diff --git a/drivers/gpu/nvgpu/gk20a/tsg_gk20a.c b/drivers/gpu/nvgpu/gk20a/tsg_gk20a.c
index c84e8d0b..98e1ae2c 100644
--- a/drivers/gpu/nvgpu/gk20a/tsg_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/tsg_gk20a.c
@@ -27,13 +27,26 @@
 
 static void gk20a_tsg_release(struct kref *ref);
 
-static void gk20a_tsg_release(struct kref *ref);
-
 bool gk20a_is_channel_marked_as_tsg(struct channel_gk20a *ch)
 {
         return !(ch->tsgid == NVGPU_INVALID_TSG_ID);
 }
 
+static bool gk20a_is_channel_active(struct gk20a *g, struct channel_gk20a *ch)
+{
+        struct fifo_gk20a *f = &g->fifo;
+        struct fifo_runlist_info_gk20a *runlist;
+        int i;
+
+        for (i = 0; i < f->max_runlists; ++i) {
+                runlist = &f->runlist_info[i];
+                if (test_bit(ch->hw_chid, runlist->active_channels))
+                        return true;
+        }
+
+        return false;
+}
+
 /*
  * API to mark channel as part of TSG
  *
@@ -50,6 +63,12 @@ static int gk20a_tsg_bind_channel(struct tsg_gk20a *tsg, int ch_fd)
                 return -EINVAL;
         }
 
+        /* channel cannot be bound to TSG if it is already active */
+        if (gk20a_is_channel_active(tsg->g, ch)) {
+                fput(f);
+                return -EINVAL;
+        }
+
         ch->tsgid = tsg->tsgid;
 
         mutex_lock(&tsg->ch_list_lock);