dma-buf: Add unlocked variant of attachment-mapping functions

[ Upstream commit 19d6634d8789573a9212ce78dbb4348ffd4f7f78 ]

Add unlocked variant of dma_buf_map/unmap_attachment() that will
be used by drivers that don't take the reservation lock explicitly.

Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221017172229.42269-3-dmitry.osipenko@collabora.com
Stable-dep-of: a2cb9cd6a394 ("misc: fastrpc: Fix incorrect DMA mapping unmap request")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index eb6b59363c4f589a1100a5301bd99d4458793acb..3d58514d04826b7b072338dcd769af09c8353b3d 100644 (file)
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -1105,6 +1105,34 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_map_attachment, DMA_BUF);
 
+/**
+ * dma_buf_map_attachment_unlocked - Returns the scatterlist table of the attachment;
+ * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the
+ * dma_buf_ops.
+ * @attach:    [in]    attachment whose scatterlist is to be returned
+ * @direction: [in]    direction of DMA transfer
+ *
+ * Unlocked variant of dma_buf_map_attachment().
+ */
+struct sg_table *
+dma_buf_map_attachment_unlocked(struct dma_buf_attachment *attach,
+                               enum dma_data_direction direction)
+{
+       struct sg_table *sg_table;
+
+       might_sleep();
+
+       if (WARN_ON(!attach || !attach->dmabuf))
+               return ERR_PTR(-EINVAL);
+
+       dma_resv_lock(attach->dmabuf->resv, NULL);
+       sg_table = dma_buf_map_attachment(attach, direction);
+       dma_resv_unlock(attach->dmabuf->resv);
+
+       return sg_table;
+}
+EXPORT_SYMBOL_NS_GPL(dma_buf_map_attachment_unlocked, DMA_BUF);
+
 /**
  * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might
  * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
@@ -1141,6 +1169,31 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
 }
 EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_attachment, DMA_BUF);
 
+/**
+ * dma_buf_unmap_attachment_unlocked - unmaps and decreases usecount of the buffer;might
+ * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of
+ * dma_buf_ops.
+ * @attach:    [in]    attachment to unmap buffer from
+ * @sg_table:  [in]    scatterlist info of the buffer to unmap
+ * @direction: [in]    direction of DMA transfer
+ *
+ * Unlocked variant of dma_buf_unmap_attachment().
+ */
+void dma_buf_unmap_attachment_unlocked(struct dma_buf_attachment *attach,
+                                      struct sg_table *sg_table,
+                                      enum dma_data_direction direction)
+{
+       might_sleep();
+
+       if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
+               return;
+
+       dma_resv_lock(attach->dmabuf->resv, NULL);
+       dma_buf_unmap_attachment(attach, sg_table, direction);
+       dma_resv_unlock(attach->dmabuf->resv);
+}
+EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_attachment_unlocked, DMA_BUF);
+
 /**
  * dma_buf_move_notify - notify attachments that DMA-buf is moving
  *

diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 71731796c8c3a8d41c4507ce66baefe4f8b0d5f6..9c31f1f430d8ec67855a3e2f7f465c5ff28dc16a 100644 (file)
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -627,6 +627,12 @@ int dma_buf_begin_cpu_access(struct dma_buf *dma_buf,
                             enum dma_data_direction dir);
 int dma_buf_end_cpu_access(struct dma_buf *dma_buf,
                           enum dma_data_direction dir);
+struct sg_table *
+dma_buf_map_attachment_unlocked(struct dma_buf_attachment *attach,
+                               enum dma_data_direction direction);
+void dma_buf_unmap_attachment_unlocked(struct dma_buf_attachment *attach,
+                                      struct sg_table *sg_table,
+                                      enum dma_data_direction direction);
 
 int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
                 unsigned long);