drm/amd/amdgpu: add missing mutex lock to amdgpu_get_xgmi_hive() (v3)

v2: Move locks around in other functions so that this
function can stand on its own.  Also only hold the hive
specific lock for add/remove device instead of the driver
global lock so you can't add/remove devices in parallel from
one hive.

v3: add reset_lock

Acked-by:  Shaoyun.liu < Shaoyun.liu@amd.com>
Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 26 insertions, 14 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
index ac57a8767283..dac187454b33 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xgmi.c
@@ -40,26 +40,40 @@ void *amdgpu_xgmi_hive_try_lock(struct amdgpu_hive_info *hive)
         return &hive->device_list;
 }
 
-struct amdgpu_hive_info *amdgpu_get_xgmi_hive(struct amdgpu_device *adev)
+struct amdgpu_hive_info *amdgpu_get_xgmi_hive(struct amdgpu_device *adev, int lock)
 {
         int i;
         struct amdgpu_hive_info *tmp;
 
         if (!adev->gmc.xgmi.hive_id)
                 return NULL;
+
+        mutex_lock(&xgmi_mutex);
+
         for (i = 0 ; i < hive_count; ++i) {
                 tmp = &xgmi_hives[i];
-                if (tmp->hive_id == adev->gmc.xgmi.hive_id)
+                if (tmp->hive_id == adev->gmc.xgmi.hive_id) {
+                        if (lock)
+                                mutex_lock(&tmp->hive_lock);
+                        mutex_unlock(&xgmi_mutex);
                         return tmp;
+                }
         }
-        if (i >= AMDGPU_MAX_XGMI_HIVE)
+        if (i >= AMDGPU_MAX_XGMI_HIVE) {
+                mutex_unlock(&xgmi_mutex);
                 return NULL;
+        }
 
         /* initialize new hive if not exist */
         tmp = &xgmi_hives[hive_count++];
         tmp->hive_id = adev->gmc.xgmi.hive_id;
         INIT_LIST_HEAD(&tmp->device_list);
         mutex_init(&tmp->hive_lock);
+        mutex_init(&tmp->reset_lock);
+        if (lock)
+                mutex_lock(&tmp->hive_lock);
+
+        mutex_unlock(&xgmi_mutex);
 
         return tmp;
 }
@@ -111,8 +125,7 @@ int amdgpu_xgmi_add_device(struct amdgpu_device *adev)
                 return ret;
         }
 
-        mutex_lock(&xgmi_mutex);
-        hive = amdgpu_get_xgmi_hive(adev);
+        hive = amdgpu_get_xgmi_hive(adev, 1);
         if (!hive) {
                 ret = -EINVAL;
                 dev_err(adev->dev,
@@ -147,8 +160,8 @@ int amdgpu_xgmi_add_device(struct amdgpu_device *adev)
                         break;
         }
 
+        mutex_unlock(&hive->hive_lock);
 exit:
-        mutex_unlock(&xgmi_mutex);
         return ret;
 }
 
@@ -159,15 +172,14 @@ void amdgpu_xgmi_remove_device(struct amdgpu_device *adev)
         if (!adev->gmc.xgmi.supported)
                 return;
 
-        mutex_lock(&xgmi_mutex);
-
-        hive = amdgpu_get_xgmi_hive(adev);
+        hive = amdgpu_get_xgmi_hive(adev, 1);
         if (!hive)
-                goto exit;
+                return;
 
-        if (!(hive->number_devices--))
+        if (!(hive->number_devices--)) {
                 mutex_destroy(&hive->hive_lock);
-
-exit:
-        mutex_unlock(&xgmi_mutex);
+                mutex_destroy(&hive->reset_lock);
+        } else {
+                mutex_unlock(&hive->hive_lock);
+        }
 }