gpu: nvgpu: Remove user_mapped from mapped_buf

Remove the always true field 'user_mapped' from the mapped_buf
struct. All mapped_bufs are mapped by a user request since they
always originate from a dma_buf (for Linux, that is). As such
there is a fair amount of logic that could be deleted.

Linux specific: the own_mem_ref field was also be deleted. The
logic of only storing a dma_buf ref when the buffer is mapped
for the first time by a user is easy: when the mapped buffer is
found in the map cache release the outstanding dma_buf ref taken
earlier on in the map path. If the map cache does not have the
buffer simply let the higher level map code keep the dma_buf ref.

The dma_buf ref is released when the nvgpu_vm_unmap_system()
call-back is called by the unmap path.

JIRA NVGPU-30
JIRA NVGPU-71

Change-Id: I229d136713812a7332bdadd5ebacd85d983bbbf0
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1583983
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 3 insertions, 5 deletions

diff --git a/drivers/gpu/nvgpu/common/mm/vm.c b/drivers/gpu/nvgpu/common/mm/vm.c
index 3d10ff48..2ce62e75 100644
--- a/drivers/gpu/nvgpu/common/mm/vm.c
+++ b/drivers/gpu/nvgpu/common/mm/vm.c
@@ -672,11 +672,9 @@ int nvgpu_vm_get_buffers(struct vm_gk20a *vm,
         nvgpu_rbtree_enum_start(0, &node, vm->mapped_buffers);
         while (node) {
                 mapped_buffer = mapped_buffer_from_rbtree_node(node);
-                if (mapped_buffer->user_mapped) {
-                        buffer_list[i] = mapped_buffer;
-                        nvgpu_ref_get(&mapped_buffer->ref);
-                        i++;
-                }
+                buffer_list[i] = mapped_buffer;
+                nvgpu_ref_get(&mapped_buffer->ref);
+                i++;
                 nvgpu_rbtree_enum_next(&node, node);
         }