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The strict > locking convention prevents deadlock situations for dma-buf importers and > exporters. > > Signed-off-by: Dmitry Osipenko Reviewed-by: Christian König > --- > 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 ceea4839c641..073942bf5ae9 100644 > --- a/drivers/dma-buf/dma-buf.c > +++ b/drivers/dma-buf/dma-buf.c > @@ -858,8 +858,8 @@ 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; > @@ -872,8 +872,7 @@ 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; > } > @@ -889,8 +888,7 @@ 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_resv_unlock(attach->dmabuf->resv); > > dma_buf_detach(dmabuf, attach); > return ERR_PTR(ret); > @@ -936,21 +934,19 @@ 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); >