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authorChris Wilson <chris@chris-wilson.co.uk>2016-08-15 16:42:18 +0100
committerSumit Semwal <sumit.semwal@linaro.org>2016-08-16 12:31:35 +0530
commitae4e46b14bd7a12fb7908425846be7ceb0853bbc (patch)
treed34ce6b16f6e83e97b7041874c97f17a5b167428 /drivers/dma-buf
parent90844f00049e9f42573fd31d7c32e8fd31d3fd07 (diff)
downloadlinux-ae4e46b14bd7a12fb7908425846be7ceb0853bbc.tar.bz2
dma-buf: Wait on the reservation object when sync'ing before CPU access
Rendering operations to the dma-buf are tracked implicitly via the reservation_object (dmabuf->resv). This is used to allow poll() to wait upon outstanding rendering (or just query the current status of rendering). The dma-buf sync ioctl allows userspace to prepare the dma-buf for CPU access, which should include waiting upon rendering. (Some drivers may need to do more work to ensure that the dma-buf mmap is coherent as well as complete.) v2: Always wait upon the reservation object implicitly. We choose to do it after the native handler in case it can do so more efficiently. Testcase: igt/prime_vgem Testcase: igt/gem_concurrent_blit # *vgem* Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Eric Anholt <eric@anholt.net> Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org> Link: http://patchwork.freedesktop.org/patch/msgid/1471275738-31994-1-git-send-email-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/dma-buf')
-rw-r--r--drivers/dma-buf/dma-buf.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index ddaee60ae52a..cf04d249a6a4 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -586,6 +586,22 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
}
EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
+static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
+ enum dma_data_direction direction)
+{
+ bool write = (direction == DMA_BIDIRECTIONAL ||
+ direction == DMA_TO_DEVICE);
+ struct reservation_object *resv = dmabuf->resv;
+ long ret;
+
+ /* Wait on any implicit rendering fences */
+ ret = reservation_object_wait_timeout_rcu(resv, write, true,
+ MAX_SCHEDULE_TIMEOUT);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
/**
* dma_buf_begin_cpu_access - Must be called before accessing a dma_buf from the
@@ -608,6 +624,13 @@ int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
if (dmabuf->ops->begin_cpu_access)
ret = dmabuf->ops->begin_cpu_access(dmabuf, direction);
+ /* Ensure that all fences are waited upon - but we first allow
+ * the native handler the chance to do so more efficiently if it
+ * chooses. A double invocation here will be reasonably cheap no-op.
+ */
+ if (ret == 0)
+ ret = __dma_buf_begin_cpu_access(dmabuf, direction);
+
return ret;
}
EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access);