gpu: nvgpu: Fix return value in pmu mutex release

Bug 1495617

Change-Id: I689ed4303bb3959bb24bf79d52891de28431fc67
Signed-off-by: Arto Merilainen <amerilainen@nvidia.com>
Reviewed-on: http://git-master/r/394904
(cherry-picked from commit a04c51430b186d23953960965ce3ab229968d1f7)
Reviewed-on: http://git-master/r/399565
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c b/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c
index 0f1af8ab..234255ce 100644
--- a/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/pmu_gk20a.c
@@ -1244,18 +1244,19 @@ int pmu_mutex_release(struct pmu_gk20a *pmu, u32 id, u32 *token)
                 return -EINVAL;
         }
 
-        if (--mutex->ref_cnt == 0) {
-                gk20a_writel(g, pwr_pmu_mutex_r(mutex->index),
-                        pwr_pmu_mutex_value_initial_lock_f());
+        if (--mutex->ref_cnt > 0)
+                return -EBUSY;
 
-                data = gk20a_readl(g, pwr_pmu_mutex_id_release_r());
-                data = set_field(data, pwr_pmu_mutex_id_release_value_m(),
-                        pwr_pmu_mutex_id_release_value_f(owner));
-                gk20a_writel(g, pwr_pmu_mutex_id_release_r(), data);
+        gk20a_writel(g, pwr_pmu_mutex_r(mutex->index),
+                pwr_pmu_mutex_value_initial_lock_f());
 
-                gk20a_dbg_pmu("mutex released: id=%d, token=0x%x",
-                        mutex->index, *token);
-        }
+        data = gk20a_readl(g, pwr_pmu_mutex_id_release_r());
+        data = set_field(data, pwr_pmu_mutex_id_release_value_m(),
+                pwr_pmu_mutex_id_release_value_f(owner));
+        gk20a_writel(g, pwr_pmu_mutex_id_release_r(), data);
+
+        gk20a_dbg_pmu("mutex released: id=%d, token=0x%x",
+                mutex->index, *token);
 
         return 0;
 }