[PATCH 2/3] wd719x: use per-command private data

Add the SCB onto the scsi command allocation and use dma streaming mappings for it only when in use. This avoid possibly calling dma_alloc_coherent under a lock or even in irq context, while also making the code simpler. Thanks to Ondrej Zary for testing and various bug fixes. Signed-off-by:

[PATCH 2/3] wd719x: use per-command private data

Add the SCB onto the scsi command allocation and use dma streaming mappings for it only when in use. This avoid possibly calling dma_alloc_coherent under a lock or even in irq context, while also making the code simpler. Signed-off-by: Christoph Hellwig --- drivers/scsi/wd719x.c | 95