drm/i915/gem: Allow backends to override pread implementation

As there are more and more complicated interactions between the different
backing stores and userspace, push the control into the backends rather
than accumulate them all inside the ioctl handlers.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20201105154934.16022-1-chris@chris-wilson.co.uk
(cherry picked from commit 0049b688459b846f819b6e51c24cd0781fcfde41)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index b5c1555..d6711ca 100644 (file)
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -56,6 +56,8 @@ struct drm_i915_gem_object_ops {
        void (*truncate)(struct drm_i915_gem_object *obj);
        void (*writeback)(struct drm_i915_gem_object *obj);
 
+       int (*pread)(struct drm_i915_gem_object *obj,
+                    const struct drm_i915_gem_pread *arg);
        int (*pwrite)(struct drm_i915_gem_object *obj,
                      const struct drm_i915_gem_pwrite *arg);
 

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index bb0c129..d58fe1d 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -527,6 +527,12 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data,
 
        trace_i915_gem_object_pread(obj, args->offset, args->size);
 
+       ret = -ENODEV;
+       if (obj->ops->pread)
+               ret = obj->ops->pread(obj, args);
+       if (ret != -ENODEV)
+               goto out;
+
        ret = i915_gem_object_wait(obj,
                                   I915_WAIT_INTERRUPTIBLE,
                                   MAX_SCHEDULE_TIMEOUT);