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drm/nouveau: try to protect nbo->pin_refcount 

... 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@ffwll.ch>
This commit is contained in:
Daniel Vetter 2012-12-11 21:52:30 +01:00
parent 59ad146542
commit 0ae6d7bc0e
2 changed files with 13 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/gpu/drm/nouveau/nouveau_bo.c
View File

@ -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;
}

2
drivers/gpu/drm/nouveau/nouveau_bo.h
View File

@ -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;