... by moving the bo_pin/bo_unpin manipulation of the pin_refcount
under the protection of the ttm reservation lock. pin/unpin seems
to get called from all over the place, so atm this is completely racy.
After this patch there are only a few places in cleanup functions
left which access ->pin_refcount without locking. But I'm hoping that
those are safe and some other code invariant guarantees that this
won't blow up.
In any case, I only need to fix up pin/unpin to make ->pageflip work
safely, so let's keep it at that.
Add a comment to the header to explain the new locking rule.
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
drivers/gpu/drm/nouveau/nouveau_bo.c | 22 +++++++++++-----------
drivers/gpu/drm/nouveau/nouveau_bo.h | 2 ++
2 files changed, 13 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 5614c89..1eb5c77 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -300,17 +300,18 @@ nouveau_bo_pin(struct nouveau_bo *nvbo, uint32_t memtype)
struct ttm_buffer_object *bo = &nvbo->bo;
int ret;
+ ret = ttm_bo_reserve(bo, false, false, false, 0);
+ if (ret)
+ goto out;
+
if (nvbo->pin_refcnt && !(memtype & (1 << bo->mem.mem_type))) {
NV_ERROR(drm, "bo %p pinned elsewhere: 0x%08x vs 0x%08x\n", bo,
1 << bo->mem.mem_type, memtype);
- return -EINVAL;
+ ret = -EINVAL;
+ goto out;
}
if (nvbo->pin_refcnt++)
- return 0;
-
- ret = ttm_bo_reserve(bo, false, false, false, 0);
- if (ret)
goto out;
nouveau_bo_placement_set(nvbo, memtype, 0);
@@ -328,10 +329,8 @@ nouveau_bo_pin(struct nouveau_bo *nvbo, uint32_t memtype)
break;
}
}
- ttm_bo_unreserve(bo);
out:
- if (unlikely(ret))
- nvbo->pin_refcnt--;
+ ttm_bo_unreserve(bo);
return ret;
}
@@ -342,13 +341,13 @@ nouveau_bo_unpin(struct nouveau_bo *nvbo)
struct ttm_buffer_object *bo = &nvbo->bo;
int ret;
- if (--nvbo->pin_refcnt)
- return 0;
-
ret = ttm_bo_reserve(bo, false, false, false, 0);
if (ret)
return ret;
+ if (--nvbo->pin_refcnt)
+ goto out;
+
nouveau_bo_placement_set(nvbo, bo->mem.placement, 0);
ret = nouveau_bo_validate(nvbo, false, false);
@@ -365,6 +364,7 @@ nouveau_bo_unpin(struct nouveau_bo *nvbo)
}
}
+out:
ttm_bo_unreserve(bo);
return ret;
}
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.h b/drivers/gpu/drm/nouveau/nouveau_bo.h
index 25ca379..81d00fe 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.h
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.h
@@ -28,6 +28,8 @@ struct nouveau_bo {
struct nouveau_drm_tile *tile;
struct drm_gem_object *gem;
+
+ /* protect by the ttm reservation lock */
int pin_refcnt;
struct ttm_bo_kmap_obj dma_buf_vmap;
--
1.7.10.4
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