Commit 809d9c72 authored by Dmitry Osipenko's avatar Dmitry Osipenko
Browse files

dma-buf: Move dma_buf_attach() to dynamic locking specification 



Move dma-buf attachment API functions to the dynamic locking specification
by taking the reservation lock around the mapping operations. The strict
locking convention prevents deadlock situations for dma-buf importers and
exporters.

Acked-by: default avatarSumit Semwal <sumit.semwal@linaro.org>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221017172229.42269-17-dmitry.osipenko@collabora.com
parent 34c7797f

drivers/dma-buf/dma-buf.c

+8 −12
Original line number Diff line number Diff line
@@ -859,8 +859,8 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, 
	    dma_buf_is_dynamic(dmabuf)) {

		struct sg_table *sgt;



		if (dma_buf_is_dynamic(attach->dmabuf)) {

		dma_resv_lock(attach->dmabuf->resv, NULL);

		if (dma_buf_is_dynamic(attach->dmabuf)) {

			ret = dmabuf->ops->pin(attach);

			if (ret)

				goto err_unlock;
@@ -873,7 +873,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, 
			ret = PTR_ERR(sgt);

			goto err_unpin;

		}

		if (dma_buf_is_dynamic(attach->dmabuf))

		dma_resv_unlock(attach->dmabuf->resv);

		attach->sgt = sgt;

		attach->dir = DMA_BIDIRECTIONAL;
@@ -890,7 +889,6 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, 
		dmabuf->ops->unpin(attach);



err_unlock:

	if (dma_buf_is_dynamic(attach->dmabuf))

	dma_resv_unlock(attach->dmabuf->resv);



	dma_buf_detach(dmabuf, attach);
@@ -937,21 +935,19 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) 
	if (WARN_ON(!dmabuf || !attach))

		return;



	if (attach->sgt) {

		if (dma_buf_is_dynamic(attach->dmabuf))

	dma_resv_lock(attach->dmabuf->resv, NULL);



	if (attach->sgt) {



		__unmap_dma_buf(attach, attach->sgt, attach->dir);



		if (dma_buf_is_dynamic(attach->dmabuf)) {

		if (dma_buf_is_dynamic(attach->dmabuf))

			dmabuf->ops->unpin(attach);

			dma_resv_unlock(attach->dmabuf->resv);

		}

	}



	dma_resv_lock(dmabuf->resv, NULL);

	list_del(&attach->node);



	dma_resv_unlock(dmabuf->resv);



	if (dmabuf->ops->detach)

		dmabuf->ops->detach(dmabuf, attach);