drm/amdgpu: fix num_ibs check

Specifying no IBs on command submission is invalid, stop crashing
badly when somebody tries it.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucer@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 5 insertions, 11 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index e7e384264202..55179efccfcf 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -211,6 +211,10 @@ int amdgpu_cs_parser_init(struct amdgpu_cs_parser *p, void *data)
                 }
         }
 
+        if (p->num_ibs == 0) {
+                ret = -EINVAL;
+                goto free_all_kdata;
+        }
 
         p->ibs = kcalloc(p->num_ibs, sizeof(struct amdgpu_ib), GFP_KERNEL);
         if (!p->ibs) {
@@ -551,9 +555,6 @@ static int amdgpu_cs_ib_vm_chunk(struct amdgpu_device *adev,
         struct amdgpu_ring *ring;
         int i, r;
 
-        if (parser->num_ibs == 0)
-                return 0;
-
         /* Only for UVD/VCE VM emulation */
         for (i = 0; i < parser->num_ibs; i++) {
                 ring = parser->ibs[i].ring;
@@ -660,9 +661,6 @@ static int amdgpu_cs_ib_fill(struct amdgpu_device *adev,
                 j++;
         }
 
-        if (!parser->num_ibs)
-                return 0;
-
         /* add GDS resources to first IB */
         if (parser->bo_list) {
                 struct amdgpu_bo *gds = parser->bo_list->gds_obj;
@@ -705,9 +703,6 @@ static int amdgpu_cs_dependencies(struct amdgpu_device *adev,
         struct amdgpu_ib *ib;
         int i, j, r;
 
-        if (!p->num_ibs)
-                return 0;
-
         /* Add dependencies to first IB */
         ib = &p->ibs[0];
         for (i = 0; i < p->nchunks; ++i) {
@@ -866,8 +861,7 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp)
         if (r)
                 goto out;
 
-        if (parser.num_ibs)
-                r = amdgpu_cs_submit(&parser, cs);
+        r = amdgpu_cs_submit(&parser, cs);
 
 out:
         amdgpu_cs_parser_fini(&parser, r, reserved_buffers);