On Fri, Jan 22, 2021 at 06:56:19PM +0200, Lauri Kasanen wrote: > > What alignment does the hardware require? > > It requires 8-byte alignment, but the buffer must also be physically > contiguous. If you want a single contiguous buffer you must use the blk_queue_max_segments() API to ask for a single contiguous segment. > I grepped around, but apparently no driver under drivers/block does > direct DMA to the bio buffer. They all use their own buffer and memcpy, > like this patch. ps3vram, ps3disk, amiflop, etc etc. > > If all existing drivers use their own buffer, why is a different > approach required for new drivers? That selections is a bunch of weirdo legacy drivers. If you want to look at something reasonably modern but still simple take a look at drivers/block/virtio_blk.c.
