[PATCH v4 08/14] nvme-pci: implement dma_token backed requests

[Christoph Hellwig]

> +static int nvme_init_dma_buf_io_ctx(struct block_device *bdev,
> +				    struct dma_buf_io_ctx *ctx)

Please stick to two-tab indents for function declaration continuation
for the nvme code to keep the code easy to maintain.

> +#if defined(CONFIG_DMA_SHARED_BUFFER)

This should be good old #ifdef.  Same in a few other places over
the series.

Modulo these minor nits the patch looks good.