From a5570178c059cec59e9835be20bc8546377fa7b5 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 4 Sep 2012 21:02:54 +0100 Subject: [PATCH] drm/i915: Pin backing pages whilst exporting through a dmabuf vmap We need to refcount our pages in order to prevent reaping them at inopportune times, such as when they currently vmapped or exported to another driver. However, we also wish to keep the lazy deallocation of our pages so we need to take a pin/unpinned approach rather than a simple refcount. Signed-off-by: Chris Wilson Reviewed-by: Ben Widawsky Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_drv.h | 12 ++++++++++++ drivers/gpu/drm/i915/i915_gem.c | 11 +++++++++-- drivers/gpu/drm/i915/i915_gem_dmabuf.c | 8 ++++++-- 3 files changed, 27 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index ada8ea172d05..12a075747dcf 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -1008,6 +1008,7 @@ struct drm_i915_gem_object { unsigned int has_global_gtt_mapping:1; struct page **pages; + int pages_pin_count; /** * DMAR support @@ -1341,6 +1342,17 @@ void i915_gem_release_mmap(struct drm_i915_gem_object *obj); void i915_gem_lastclose(struct drm_device *dev); int __must_check i915_gem_object_get_pages(struct drm_i915_gem_object *obj); +static inline void i915_gem_object_pin_pages(struct drm_i915_gem_object *obj) +{ + BUG_ON(obj->pages == NULL); + obj->pages_pin_count++; +} +static inline void i915_gem_object_unpin_pages(struct drm_i915_gem_object *obj) +{ + BUG_ON(obj->pages_pin_count == 0); + obj->pages_pin_count--; +} + int __must_check i915_mutex_lock_interruptible(struct drm_device *dev); int i915_gem_object_sync(struct drm_i915_gem_object *obj, struct intel_ring_buffer *to); diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 4b2ee7ce8b15..ea3a5e1791e9 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1699,6 +1699,9 @@ i915_gem_object_put_pages(struct drm_i915_gem_object *obj) BUG_ON(obj->gtt_space); + if (obj->pages_pin_count) + return -EBUSY; + ops->put_pages(obj); list_del(&obj->gtt_list); @@ -1837,6 +1840,8 @@ i915_gem_object_get_pages(struct drm_i915_gem_object *obj) if (obj->sg_table || obj->pages) return 0; + BUG_ON(obj->pages_pin_count); + ret = ops->get_pages(obj); if (ret) return ret; @@ -3743,6 +3748,7 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj) dev_priv->mm.interruptible = was_interruptible; } + obj->pages_pin_count = 0; i915_gem_object_put_pages(obj); i915_gem_object_free_mmap_offset(obj); @@ -4402,9 +4408,10 @@ i915_gem_inactive_shrink(struct shrinker *shrinker, struct shrink_control *sc) cnt = 0; list_for_each_entry(obj, &dev_priv->mm.unbound_list, gtt_list) - cnt += obj->base.size >> PAGE_SHIFT; + if (obj->pages_pin_count == 0) + cnt += obj->base.size >> PAGE_SHIFT; list_for_each_entry(obj, &dev_priv->mm.bound_list, gtt_list) - if (obj->pin_count == 0) + if (obj->pin_count == 0 && obj->pages_pin_count == 0) cnt += obj->base.size >> PAGE_SHIFT; mutex_unlock(&dev->struct_mutex); diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c index e4f114198e4d..eca4726f414d 100644 --- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c @@ -50,6 +50,8 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme /* link the pages into an SG then map the sg */ sg = drm_prime_pages_to_sg(obj->pages, npages); nents = dma_map_sg(attachment->dev, sg->sgl, sg->nents, dir); + i915_gem_object_pin_pages(obj); + out: mutex_unlock(&dev->struct_mutex); return sg; @@ -102,6 +104,7 @@ static void *i915_gem_dmabuf_vmap(struct dma_buf *dma_buf) } obj->vmapping_count = 1; + i915_gem_object_pin_pages(obj); out_unlock: mutex_unlock(&dev->struct_mutex); return obj->dma_buf_vmapping; @@ -117,10 +120,11 @@ static void i915_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr) if (ret) return; - --obj->vmapping_count; - if (obj->vmapping_count == 0) { + if (--obj->vmapping_count == 0) { vunmap(obj->dma_buf_vmapping); obj->dma_buf_vmapping = NULL; + + i915_gem_object_unpin_pages(obj); } mutex_unlock(&dev->struct_mutex); }