Synchronize dma and cpu view of scatterlist buffer(s)
void usb_buffer_dmasync_sg(const struct usb_device * dev, int is_in, struct scatterlist * sg, int n_hw_ents);
dev
device to which the scatterlist will be mapped
is_in
mapping transfer direction
sg
the scatterlist to synchronize
n_hw_ents
the positive return value from usb_buffer_map_sg
Use this when you are re-using a scatterlist's data buffers for another USB request.