[PATCH 52/88] drm/amdgpu: remove unsafe context releasing

[Alex Deucher]

From: Marek Olšák <marek.ol...@amd.com>

If ctx was released between put and get, then "get" would crash.

Signed-off-by: Marek Olšák <marek.olsak at amd.com>
Reviewed-by: Christian König <christian.koenig at amd.com>
Reviewed-by: Jammy Zhou <Jammy.Zhou at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index 235010a..ffb13a6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -69,7 +69,6 @@ int amdgpu_ctx_alloc(struct amdgpu_device *adev, struct 
amdgpu_fpriv *fpriv, uin

 int amdgpu_ctx_free(struct amdgpu_device *adev, struct amdgpu_fpriv *fpriv, 
uint32_t id)
 {
-       int r;
        struct amdgpu_ctx *ctx;
        struct amdgpu_ctx_mgr *mgr = &fpriv->ctx_mgr;

@@ -77,15 +76,8 @@ int amdgpu_ctx_free(struct amdgpu_device *adev, struct 
amdgpu_fpriv *fpriv, uint
        ctx = idr_find(&mgr->ctx_handles, id);
        rcu_read_unlock();
        if (ctx) {
-               /* if no task is pending on this context, free it */
-               r = kref_put(&ctx->refcount, amdgpu_ctx_do_release);
-               if (r == 1)
-                       return 0;//context is removed successfully
-               else {
-                       /* context is still in using */
-                       kref_get(&ctx->refcount);
-                       return -ERESTARTSYS;
-               }
+               kref_put(&ctx->refcount, amdgpu_ctx_do_release);
+               return 0;
        }
        return -EINVAL;
 }
-- 
1.8.3.1