[PATCH 01/13] drm/i915: fall through pwrite_gtt_slow to the shmem slow path

Daniel Vetter
2011-11-06T19:13:48Z

The gtt_pwrite slowpath grabs the userspace memory with
get_user_pages. This will not work for non-page backed memory, like a
gtt mmapped gem object. Hence fall throuh to the shmem paths if we hit
-EFAULT in the gtt paths.

Now the shmem paths have exactly the same problem, but this way we
only need to rearrange the code in one write path.

v2: v1 accidentaly falls back to shmem pwrite for phys objects. Fixed.

Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/i915/i915_gem.c | 31 +++++++++++++++++++------------
1 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a838597..6fa24bc 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -996,10 +996,11 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
* pread/pwrite currently are reading and writing from the CPU
* perspective, requiring manual detiling by the client.
*/
- if (obj->phys_obj)
+ if (obj->phys_obj) {
ret = i915_gem_phys_pwrite(dev, obj, args, file);
- else if (obj->gtt_space &&
- obj->base.write_domain != I915_GEM_DOMAIN_CPU) {
+ goto out;
+ } else if (obj->gtt_space &&
+ obj->base.write_domain != I915_GEM_DOMAIN_CPU) {
ret = i915_gem_object_pin(obj, 0, true);
if (ret)
goto out;
@@ -1018,18 +1019,24 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,

out_unpin:
i915_gem_object_unpin(obj);
- } else {
- ret = i915_gem_object_set_to_cpu_domain(obj, 1);
- if (ret)
- goto out;

- ret = -EFAULT;
- if (!i915_gem_object_needs_bit17_swizzle(obj))
- ret = i915_gem_shmem_pwrite_fast(dev, obj, args, file);
- if (ret == -EFAULT)
- ret = i915_gem_shmem_pwrite_slow(dev, obj, args, file);
+ if (ret != -EFAULT)
+ goto out;
+ /* Fall through to the shmfs paths because the gtt paths might
+ * fail with non-page-backed user pointers (e.g. gtt mappings
+ * when moving data between textures). */
}

+ ret = i915_gem_object_set_to_cpu_domain(obj, 1);
+ if (ret)
+ goto out;
+
+ ret = -EFAULT;
+ if (!i915_gem_object_needs_bit17_swizzle(obj))
+ ret = i915_gem_shmem_pwrite_fast(dev, obj, args, file);
+ if (ret == -EFAULT)
+ ret = i915_gem_shmem_pwrite_slow(dev, obj, args, file);
+
out:
drm_gem_object_unreference(&obj->base);
unlock:
--
1.7.6.4