Difference b/w xfer_len and len fields

[Ian Lepore]

On Sat, 2015-05-30 at 11:26 +0530, Pratik Singhal wrote:
> What is the difference b/w the xfer_len and the len fields in the struct
> mmc_data in file sys/dev/mmc/mmcreg.h  ?
> 
> AFAIK , len is the length of the data present in mmc_data , what is
> xfer_len ?
> 

The xfer_len field has historically been unused, until recently.  When
the dwc mmc driver was added, it uses xfer_len as a driver-internal
variable to track how much of the overal work is done as the IO
proceeds.

-- Ian