diff mbox series

[v4,16/21] dma-buf: Move dma_buf_attach() to dynamic locking specification

Message ID 20220831153757.97381-17-dmitry.osipenko@collabora.com (mailing list archive)
State New, archived
Headers show
Series Move all drivers to a common dma-buf locking convention | expand

Commit Message

Dmitry Osipenko Aug. 31, 2022, 3:37 p.m. UTC 
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.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 drivers/dma-buf/dma-buf.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)
diff mbox series

Patch

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);