[Intel-gfx] [PATCH 36/61] drm/i915: Add ww locking to dma-buf ops.

Maarten Lankhorst
2020-10-02T13:00:20Z

vmap is using pin_pages, but needs to use ww locking,
add pin_pages_unlocked to correctly lock the mapping.

Also add ww locking to begin/end cpu access.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 60 ++++++++++++----------
1 file changed, 33 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index 131ec53d8521..dfd483147b73 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -82,7 +82,7 @@ static int i915_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct dma_buf_map *map
struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
void *vaddr;

- vaddr = i915_gem_object_pin_map(obj, I915_MAP_WB);
+ vaddr = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WB);
if (IS_ERR(vaddr))
return PTR_ERR(vaddr);

@@ -124,42 +124,48 @@ static int i915_gem_begin_cpu_access(struct dma_buf *dma_buf, enum dma_data_dire
{
struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
bool write = (direction == DMA_BIDIRECTIONAL || direction == DMA_TO_DEVICE);
+ struct i915_gem_ww_ctx ww;
int err;

- err = i915_gem_object_pin_pages(obj);
- if (err)
- return err;
-
- err = i915_gem_object_lock_interruptible(obj, NULL);
- if (err)
- goto out;
-
- err = i915_gem_object_set_to_cpu_domain(obj, write);
- i915_gem_object_unlock(obj);
-
-out:
- i915_gem_object_unpin_pages(obj);
+ i915_gem_ww_ctx_init(&ww, true);
+retry:
+ err = i915_gem_object_lock(obj, &ww);
+ if (!err)
+ err = i915_gem_object_pin_pages(obj);
+ if (!err) {
+ err = i915_gem_object_set_to_cpu_domain(obj, write);
+ i915_gem_object_unpin_pages(obj);
+ }
+ if (err == -EDEADLK) {
+ err = i915_gem_ww_ctx_backoff(&ww);
+ if (!err)
+ goto retry;
+ }
+ i915_gem_ww_ctx_fini(&ww);
return err;
}

static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
{
struct drm_i915_gem_object *obj = dma_buf_to_obj(dma_buf);
+ struct i915_gem_ww_ctx ww;
int err;

- err = i915_gem_object_pin_pages(obj);
- if (err)
- return err;
-
- err = i915_gem_object_lock_interruptible(obj, NULL);
- if (err)
- goto out;
-
- err = i915_gem_object_set_to_gtt_domain(obj, false);
- i915_gem_object_unlock(obj);
-
-out:
- i915_gem_object_unpin_pages(obj);
+ i915_gem_ww_ctx_init(&ww, true);
+retry:
+ err = i915_gem_object_lock(obj, &ww);
+ if (!err)
+ err = i915_gem_object_pin_pages(obj);
+ if (!err) {
+ err = i915_gem_object_set_to_gtt_domain(obj, false);
+ i915_gem_object_unpin_pages(obj);
+ }
+ if (err == -EDEADLK) {
+ err = i915_gem_ww_ctx_backoff(&ww);
+ if (!err)
+ goto retry;
+ }
+ i915_gem_ww_ctx_fini(&ww);
return err;