[PATCH 2/2] drm/i915/gem: Migrate to system at dma-buf map time

[Thomas Hellström]

Until we support p2p dma or as a complement to that, migrate data
to system memory at dma-buf map time if possible.

v2:
- Rebase on dynamic exporter. Update the igt_dmabuf_import_same_driver
  selftest to migrate if we are LMEM capable.
v3:
- Migrate also in the pin() callback.

Signed-off-by: Thomas Hellström <thomas.hellst...@linux.intel.com>
Reviewed-by: Michael J. Ruhl <michael.j.r...@intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c    | 21 +++++++++++++++++--
 .../drm/i915/gem/selftests/i915_gem_dmabuf.c  |  4 +++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c 
b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index 918c19df7b66..13312d89c2ed 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -34,7 +34,14 @@ static struct sg_table *i915_gem_map_dma_buf(struct 
dma_buf_attachment *attachme
         * Let's pin it here to avoid having to call the move_notify
         * callback, The call of which is not yet implemented.
         */
-       ret = i915_gem_object_pin_pages(obj);
+       if (!i915_gem_object_can_migrate(obj, INTEL_REGION_SMEM))
+               return ERR_PTR(-EOPNOTSUPP);
+
+       ret = i915_gem_object_migrate(obj, NULL, INTEL_REGION_SMEM);
+       if (!ret)
+               ret = i915_gem_object_wait_migration(obj, 0);
+       if (!ret)
+               ret = i915_gem_object_pin_pages(obj);
        if (ret)
                goto err;
 
@@ -180,9 +187,19 @@ static int i915_gem_end_cpu_access(struct dma_buf 
*dma_buf, enum dma_data_direct
 static int i915_gem_dmabuf_pin(struct dma_buf_attachment *attach)
 {
        struct drm_i915_gem_object *obj = dma_buf_to_obj(attach->dmabuf);
+       int ret;
 
        assert_object_held(obj);
-       return i915_gem_object_pin_pages(obj);
+
+       if (!i915_gem_object_can_migrate(obj, INTEL_REGION_SMEM))
+               return -EOPNOTSUPP;
+       ret = i915_gem_object_migrate(obj, NULL, INTEL_REGION_SMEM);
+       if (!ret)
+               ret = i915_gem_object_wait_migration(obj, 0);
+       if (!ret)
+               ret = i915_gem_object_pin_pages(obj);
+
+       return ret;
 }
 
 static void i915_gem_dmabuf_unpin(struct dma_buf_attachment *attach)
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c 
b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
index 868b3469ecbd..b1e87ec08741 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
@@ -106,7 +106,9 @@ static int igt_dmabuf_import_same_driver(void *arg)
        int err;
 
        force_different_devices = true;
-       obj = i915_gem_object_create_shmem(i915, PAGE_SIZE);
+       obj = i915_gem_object_create_lmem(i915, PAGE_SIZE, 0);
+       if (IS_ERR(obj))
+               obj = i915_gem_object_create_shmem(i915, PAGE_SIZE);
        if (IS_ERR(obj))
                goto out_ret;
 
-- 
2.31.1