[PATCH] drm/amdgpu:resolv deadlock between reset and cs_ioctl

[Monk Liu]

need to unreserve ttm bo before "cs_add_fence" and "entity_push_job"
otherwise there will be deadlock between "recover_vram_from_shadow"
and previous two routines on the ttm bo's resv lock.

Change-Id: I9c18b677e474ce5b45a9cc24da3fa255d77b3d44
Signed-off-by: Monk Liu <monk....@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 35 ++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index c1f1ae9..823ac12 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -736,26 +736,12 @@ static int amdgpu_cs_sync_rings(struct amdgpu_cs_parser 
*p)
 /**
  * cs_parser_fini() - clean parser states
  * @parser:    parser structure holding parsing context.
- * @error:     error number
- *
- * If error is set than unvalidate buffer, otherwise just free memory
- * used by parsing context.
  **/
-static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser, int error, 
bool backoff)
+static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser)
 {
        struct amdgpu_fpriv *fpriv = parser->filp->driver_priv;
        unsigned i;
 
-       if (!error) {
-               amdgpu_vm_move_pt_bos_in_lru(parser->adev, &fpriv->vm);
-
-               ttm_eu_fence_buffer_objects(&parser->ticket,
-                                           &parser->validated,
-                                           parser->fence);
-       } else if (backoff) {
-               ttm_eu_backoff_reservation(&parser->ticket,
-                                          &parser->validated);
-       }
        fence_put(parser->fence);
 
        if (parser->ctx)
@@ -1075,6 +1061,16 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
        job->owner = p->filp;
        job->fence_ctx = entity->fence_context;
        p->fence = fence_get(&job->base.s_fence->finished);
+
+       /* hook sched fence to all BOs' reservation in validated list
+        * and unreserve them.
+        *
+        * we unreserve at here is because otherwise
+        * there'll be deadlock between ctx_add_fence/sched_entity_push_job
+        * and gpu_reset routine's recover_bo_from_shadow on PD/PTEs' ttm bo 
lock
+        */
+       ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence);
+
        r = amdgpu_ctx_add_fence(p->ctx, ring, p->fence, &seq);
        if (r) {
                fence_put(p->fence);
@@ -1095,6 +1091,7 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, 
struct drm_file *filp)
 {
        struct amdgpu_device *adev = dev->dev_private;
        union drm_amdgpu_cs *cs = data;
+       struct amdgpu_fpriv *fpriv;
        struct amdgpu_cs_parser parser = {};
        bool reserved_buffers = false;
        int i, r;
@@ -1104,6 +1101,7 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, 
struct drm_file *filp)
 
        parser.adev = adev;
        parser.filp = filp;
+       fpriv = filp->driver_priv;
 
        r = amdgpu_cs_parser_init(&parser, data);
        if (r) {
@@ -1141,7 +1139,12 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, 
struct drm_file *filp)
        r = amdgpu_cs_submit(&parser, cs);
 
 out:
-       amdgpu_cs_parser_fini(&parser, r, reserved_buffers);
+       if (!r)
+               amdgpu_vm_move_pt_bos_in_lru(parser.adev, &fpriv->vm);
+       else if (reserved_buffers)
+               ttm_eu_backoff_reservation(&parser.ticket, &parser.validated);
+
+       amdgpu_cs_parser_fini(&parser);
        return r;
 }
 
-- 
2.7.4

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