From 809d9c72c2f83ef7225379908e125eb4b662232c Mon Sep 17 00:00:00 2001 From: Dmitry Osipenko Date: Mon, 17 Oct 2022 20:22:24 +0300 Subject: [PATCH] dma-buf: Move dma_buf_attach() to dynamic locking specification MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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: Sumit Semwal Reviewed-by: Christian König Signed-off-by: Dmitry Osipenko Link: https://patchwork.freedesktop.org/patch/msgid/20221017172229.42269-17-dmitry.osipenko@collabora.com --- drivers/dma-buf/dma-buf.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 2c4381b..d685a5a 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -859,8 +859,8 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, dma_buf_is_dynamic(dmabuf)) { struct sg_table *sgt; + dma_resv_lock(attach->dmabuf->resv, NULL); if (dma_buf_is_dynamic(attach->dmabuf)) { - dma_resv_lock(attach->dmabuf->resv, NULL); ret = dmabuf->ops->pin(attach); if (ret) goto err_unlock; @@ -873,8 +873,7 @@ 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); + dma_resv_unlock(attach->dmabuf->resv); attach->sgt = sgt; attach->dir = DMA_BIDIRECTIONAL; } @@ -890,8 +889,7 @@ err_unpin: dmabuf->ops->unpin(attach); err_unlock: - if (dma_buf_is_dynamic(attach->dmabuf)) - dma_resv_unlock(attach->dmabuf->resv); + dma_resv_unlock(attach->dmabuf->resv); dma_buf_detach(dmabuf, attach); return ERR_PTR(ret); @@ -937,21 +935,19 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) if (WARN_ON(!dmabuf || !attach)) return; + dma_resv_lock(attach->dmabuf->resv, NULL); + if (attach->sgt) { - if (dma_buf_is_dynamic(attach->dmabuf)) - dma_resv_lock(attach->dmabuf->resv, NULL); __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); -- 2.7.4