[PATCH 3/3] drm/i915: rename & update eb_select_ring()

Dave Gordon
2016-07-20T17:16:18Z

'ring' is an old deprecated term for a GPU engine, so we're trying to
phase out all such terminology. eb_select_ring() not only has 'ring'
(meaning engine) in its name, but it has an ugly calling convention
whereby it returns an errno and stores a pointer-to-engine indirectly
through an output parameter. As there is only one error it ever returns
(-EINVAL), we can make it return the pointer directly, and have the
caller pass back the error code -EINVAL if the pointer result is NULL.

Thus we can replace
- ret = eb_select_ring(dev_priv, file, args, &engine);
- if (ret)
- return ret;
with
+ engine = eb_select_engine(dev_priv, file, args);
+ if (!engine)
+ return -EINVAL;
for increased clarity and maybe save a few cycles too.

Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
---
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 32 +++++++++++++++---------------
1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 6482ec2..f8d8ae3 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1380,24 +1380,24 @@ static bool only_mappable_for_reloc(unsigned int flags)
[I915_EXEC_VEBOX] = VECS
};

-static int
-eb_select_ring(struct drm_i915_private *dev_priv,
- struct drm_file *file,
- struct drm_i915_gem_execbuffer2 *args,
- struct intel_engine_cs **ring)
+static struct intel_engine_cs *
+eb_select_engine(struct drm_i915_private *dev_priv,
+ struct drm_file *file,
+ struct drm_i915_gem_execbuffer2 *args)
{
unsigned int user_ring_id = args->flags & I915_EXEC_RING_MASK;
+ struct intel_engine_cs *engine;

if (user_ring_id > I915_USER_RINGS) {
DRM_DEBUG("execbuf with unknown ring: %u\n", user_ring_id);
- return -EINVAL;
+ return NULL;
}

if ((user_ring_id != I915_EXEC_BSD) &&
((args->flags & I915_EXEC_BSD_MASK) != 0)) {
DRM_DEBUG("execbuf with non bsd ring but with invalid "
"bsd dispatch flags: %d\n", (int)(args->flags));
- return -EINVAL;
+ return NULL;
}

if (user_ring_id == I915_EXEC_BSD && HAS_BSD2(dev_priv)) {
@@ -1412,20 +1412,20 @@ static bool only_mappable_for_reloc(unsigned int flags)
} else {
DRM_DEBUG("execbuf with unknown bsd ring: %u\n",
bsd_idx);
- return -EINVAL;
+ return NULL;
}

- *ring = &dev_priv->engine[_VCS(bsd_idx)];
+ engine = &dev_priv->engine[_VCS(bsd_idx)];
} else {
- *ring = &dev_priv->engine[user_ring_map[user_ring_id]];
+ engine = &dev_priv->engine[user_ring_map[user_ring_id]];
}

- if (!intel_engine_initialized(*ring)) {
+ if (!intel_engine_initialized(engine)) {
DRM_DEBUG("execbuf with invalid ring: %u\n", user_ring_id);
- return -EINVAL;
+ return NULL;
}

- return 0;
+ return engine;
}

static int
@@ -1467,9 +1467,9 @@ static bool only_mappable_for_reloc(unsigned int flags)
if (args->flags & I915_EXEC_IS_PINNED)
dispatch_flags |= I915_DISPATCH_PINNED;

- ret = eb_select_ring(dev_priv, file, args, &engine);
- if (ret)
- return ret;
+ engine = eb_select_engine(dev_priv, file, args);
+ if (!engine)
+ return -EINVAL;

if (args->buffer_count < 1) {
DRM_DEBUG("execbuf with %d buffers\n", args->buffer_count);
--
1.9.1