This way we always call the the map/unmap callbacks with the reservation
object held if pin/unpin is also implemented.
For static dma-buf exporters we still have the fallback of using cached sgt.
v2: reordered
v3: rebased on sgt caching
v4: use the cached sgt when possible
v5: cleanup further
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
---
drivers/dma-buf/dma-buf.c | 10 +++++-----
include/linux/dma-buf.h | 3 +++
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index a18d10c4425a..0aa97bb05636 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -691,13 +691,15 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
reservation_object_lock(attach->dmabuf->resv, NULL);
r = dma_buf_pin(attach->dmabuf);
- reservation_object_unlock(attach->dmabuf->resv);
- if (r)
+ if (r) {
+ reservation_object_unlock(attach->dmabuf->resv);
return ERR_PTR(r);
+ }
sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
if (!sg_table)
sg_table = ERR_PTR(-ENOMEM);
+ reservation_object_unlock(attach->dmabuf->resv);
return sg_table;
}
@@ -725,10 +727,8 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
if (attach->sgt == sg_table)
return;
- attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
- direction);
-
reservation_object_lock(attach->dmabuf->resv, NULL);
+ attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction);
dma_buf_unpin(attach->dmabuf);
reservation_object_unlock(attach->dmabuf->resv);
}
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index b9d0719581cd..425a771d229c 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -144,6 +144,9 @@ struct dma_buf_ops {
* any other kind of sharing that the exporter might wish to make
* available to buffer-users.
*
+ * This is always called with the dmabuf->resv object locked when
+ * the pin/unpin callbacks are implemented.
+ *
* Returns:
*
* A &sg_table scatter list of or the backing storage of the DMA buffer,
--
2.17.1
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