[PATCH 01/13] drm/i915: Refactor shmem pread setup

bradley.d.volkin
2014-02-18T18:19:50Z

From: Brad Volkin <bradley.d.volkin@intel.com>

The command parser is going to need the same synchronization and
setup logic, so factor it out for reuse.

v2: Add a check that the object is backed by shmem

Signed-off-by: Brad Volkin <bradley.d.volkin@intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 3 +++
drivers/gpu/drm/i915/i915_gem.c | 51 ++++++++++++++++++++++++++++++-----------
2 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 8c64831..582035b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2097,6 +2097,9 @@ void i915_gem_release_all_mmaps(struct drm_i915_private *dev_priv);
void i915_gem_release_mmap(struct drm_i915_gem_object *obj);
void i915_gem_lastclose(struct drm_device *dev);

+int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj,
+ int *needs_clflush);
+
int __must_check i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
static inline struct page *i915_gem_object_get_page(struct drm_i915_gem_object *obj, int n)
{
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 3618bb0..83990cb 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -326,6 +326,42 @@ __copy_from_user_swizzled(char *gpu_vaddr, int gpu_offset,
return 0;
}

+/*
+ * Pins the specified object's pages and synchronizes the object with
+ * GPU accesses. Sets needs_clflush to non-zero if the caller should
+ * flush the object from the CPU cache.
+ */
+int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj,
+ int *needs_clflush)
+{
+ int ret;
+
+ *needs_clflush = 0;
+
+ if (!obj->base.filp)
+ return -EINVAL;
+
+ if (!(obj->base.read_domains & I915_GEM_DOMAIN_CPU)) {
+ /* If we're not in the cpu read domain, set ourself into the gtt
+ * read domain and manually flush cachelines (if required). This
+ * optimizes for the case when the gpu will dirty the data
+ * anyway again before the next pread happens. */
+ *needs_clflush = !cpu_cache_is_coherent(obj->base.dev,
+ obj->cache_level);
+ ret = i915_gem_object_wait_rendering(obj, true);
+ if (ret)
+ return ret;
+ }
+
+ ret = i915_gem_object_get_pages(obj);
+ if (ret)
+ return ret;
+
+ i915_gem_object_pin_pages(obj);
+
+ return ret;
+}
+
/* Per-page copy function for the shmem pread fastpath.
* Flushes invalid cachelines before reading the target if
* needs_clflush is set. */
@@ -423,23 +459,10 @@ i915_gem_shmem_pread(struct drm_device *dev,

obj_do_bit17_swizzling = i915_gem_object_needs_bit17_swizzle(obj);

- if (!(obj->base.read_domains & I915_GEM_DOMAIN_CPU)) {
- /* If we're not in the cpu read domain, set ourself into the gtt
- * read domain and manually flush cachelines (if required). This
- * optimizes for the case when the gpu will dirty the data
- * anyway again before the next pread happens. */
- needs_clflush = !cpu_cache_is_coherent(dev, obj->cache_level);
- ret = i915_gem_object_wait_rendering(obj, true);
- if (ret)
- return ret;
- }
-
- ret = i915_gem_object_get_pages(obj);
+ ret = i915_gem_obj_prepare_shmem_read(obj, &needs_clflush);
if (ret)
return ret;

- i915_gem_object_pin_pages(obj);
-
offset = args->offset;

for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents,
--
1.8.3.2