usb_sg_init — initializes scatterlist-based bulk/interrupt I/O request
|struct usb_sg_request * io,|
|struct usb_device * dev,|
|struct scatterlist * sg,|
request block being initialized. until
treat this as a pointer to an opaque block of memory,
the usb device that will send or receive the data
endpoint “pipe” used to transfer the data
polling rate for interrupt endpoints, in frames or (for high speed endpoints) microframes; ignored for bulk
how many entries in the scatterlist
how many bytes to send from the scatterlist, or zero to send every byte identified in the list.
SLAB_* flags affecting memory allocations in this call
This initializes a scatter/gather request, allocating resources such as I/O mappings and urb memory (except maybe memory used by USB controller drivers).