3 files changed, 62 insertions, 12 deletions

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index b316b301152f..85ef693850e7 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -1142,6 +1142,48 @@ struct r600_vram_scratch {
         u64                             gpu_addr;
 };
 
+
+/*
+ * Mutex which allows recursive locking from the same process.
+ */
+struct radeon_mutex {
+        struct mutex            mutex;
+        struct task_struct      *owner;
+        int                     level;
+};
+
+static inline void radeon_mutex_init(struct radeon_mutex *mutex)
+{
+        mutex_init(&mutex->mutex);
+        mutex->owner = NULL;
+        mutex->level = 0;
+}
+
+static inline void radeon_mutex_lock(struct radeon_mutex *mutex)
+{
+        if (mutex_trylock(&mutex->mutex)) {
+                /* The mutex was unlocked before, so it's ours now */
+                mutex->owner = current;
+        } else if (mutex->owner != current) {
+                /* Another process locked the mutex, take it */
+                mutex_lock(&mutex->mutex);
+                mutex->owner = current;
+        }
+        /* Otherwise the mutex was already locked by this process */
+
+        mutex->level++;
+}
+
+static inline void radeon_mutex_unlock(struct radeon_mutex *mutex)
+{
+        if (--mutex->level > 0)
+                return;
+
+        mutex->owner = NULL;
+        mutex_unlock(&mutex->mutex);
+}
+
+
 /*
  * Core structure, functions and helpers.
  */
@@ -1197,7 +1239,7 @@ struct radeon_device {
         struct radeon_gem               gem;
         struct radeon_pm                pm;
         uint32_t                        bios_scratch[RADEON_BIOS_NUM_SCRATCH];
-        struct mutex                    cs_mutex;
+        struct radeon_mutex             cs_mutex;
         struct radeon_wb                wb;
         struct radeon_dummy_page        dummy_page;
         bool                            gpu_lockup;
diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c
index fae00c0d75aa..ccaa243c1442 100644
--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -222,7 +222,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
         struct radeon_cs_chunk *ib_chunk;
         int r;
 
-        mutex_lock(&rdev->cs_mutex);
+        radeon_mutex_lock(&rdev->cs_mutex);
         /* initialize parser */
         memset(&parser, 0, sizeof(struct radeon_cs_parser));
         parser.filp = filp;
@@ -233,14 +233,14 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
         if (r) {
                 DRM_ERROR("Failed to initialize parser !\n");
                 radeon_cs_parser_fini(&parser, r);
-                mutex_unlock(&rdev->cs_mutex);
+                radeon_mutex_unlock(&rdev->cs_mutex);
                 return r;
         }
         r =  radeon_ib_get(rdev, &parser.ib);
         if (r) {
                 DRM_ERROR("Failed to get ib !\n");
                 radeon_cs_parser_fini(&parser, r);
-                mutex_unlock(&rdev->cs_mutex);
+                radeon_mutex_unlock(&rdev->cs_mutex);
                 return r;
         }
         r = radeon_cs_parser_relocs(&parser);
@@ -248,7 +248,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
                 if (r != -ERESTARTSYS)
                         DRM_ERROR("Failed to parse relocation %d!\n", r);
                 radeon_cs_parser_fini(&parser, r);
-                mutex_unlock(&rdev->cs_mutex);
+                radeon_mutex_unlock(&rdev->cs_mutex);
                 return r;
         }
         /* Copy the packet into the IB, the parser will read from the
@@ -260,14 +260,14 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
         if (r || parser.parser_error) {
                 DRM_ERROR("Invalid command stream !\n");
                 radeon_cs_parser_fini(&parser, r);
-                mutex_unlock(&rdev->cs_mutex);
+                radeon_mutex_unlock(&rdev->cs_mutex);
                 return r;
         }
         r = radeon_cs_finish_pages(&parser);
         if (r) {
                 DRM_ERROR("Invalid command stream !\n");
                 radeon_cs_parser_fini(&parser, r);
-                mutex_unlock(&rdev->cs_mutex);
+                radeon_mutex_unlock(&rdev->cs_mutex);
                 return r;
         }
         r = radeon_ib_schedule(rdev, parser.ib);
@@ -275,7 +275,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
                 DRM_ERROR("Failed to schedule IB !\n");
         }
         radeon_cs_parser_fini(&parser, r);
-        mutex_unlock(&rdev->cs_mutex);
+        radeon_mutex_unlock(&rdev->cs_mutex);
         return r;
 }
 
diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index c33bc914d93d..c4d00a171411 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -716,7 +716,7 @@ int radeon_device_init(struct radeon_device *rdev,
 
         /* mutex initialization are all done here so we
          * can recall function without having locking issues */
-        mutex_init(&rdev->cs_mutex);
+        radeon_mutex_init(&rdev->cs_mutex);
         mutex_init(&rdev->ib_pool.mutex);
         mutex_init(&rdev->cp.mutex);
         mutex_init(&rdev->dc_hw_i2c_mutex);
@@ -955,6 +955,9 @@ int radeon_gpu_reset(struct radeon_device *rdev)
         int r;
         int resched;
 
+        /* Prevent CS ioctl from interfering */
+        radeon_mutex_lock(&rdev->cs_mutex);
+
         radeon_save_bios_scratch_regs(rdev);
         /* block TTM */
         resched = ttm_bo_lock_delayed_workqueue(&rdev->mman.bdev);
@@ -967,10 +970,15 @@ int radeon_gpu_reset(struct radeon_device *rdev)
                 radeon_restore_bios_scratch_regs(rdev);
                 drm_helper_resume_force_mode(rdev->ddev);
                 ttm_bo_unlock_delayed_workqueue(&rdev->mman.bdev, resched);
-                return 0;
         }
-        /* bad news, how to tell it to userspace ? */
-        dev_info(rdev->dev, "GPU reset failed\n");
+
+        radeon_mutex_unlock(&rdev->cs_mutex);
+
+        if (r) {
+                /* bad news, how to tell it to userspace ? */
+                dev_info(rdev->dev, "GPU reset failed\n");
+        }
+
         return r;
 }