1USB_SG_INIT(9)                   USB Core APIs                  USB_SG_INIT(9)
2
3
4

NAME

6       usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
7

SYNOPSIS

9       int usb_sg_init(struct usb_sg_request * io, struct usb_device * dev,
10                       unsigned pipe, unsigned period,
11                       struct scatterlist * sg, int nents, size_t length,
12                       gfp_t mem_flags);
13

ARGUMENTS

15       io
16           request block being initialized. until usb_sg_wait returns, treat
17           this as a pointer to an opaque block of memory,
18
19       dev
20           the usb device that will send or receive the data
21
22       pipe
23           endpoint “pipe” used to transfer the data
24
25       period
26           polling rate for interrupt endpoints, in frames or (for high speed
27           endpoints) microframes; ignored for bulk
28
29       sg
30           scatterlist entries
31
32       nents
33           how many entries in the scatterlist
34
35       length
36           how many bytes to send from the scatterlist, or zero to send every
37           byte identified in the list.
38
39       mem_flags
40           SLAB_* flags affecting memory allocations in this call
41

DESCRIPTION

43       This initializes a scatter/gather request, allocating resources such as
44       I/O mappings and urb memory (except maybe memory used by USB controller
45       drivers).
46
47       The request must be issued using usb_sg_wait, which waits for the I/O
48       to complete (or to be canceled) and then cleans up all resources
49       allocated by usb_sg_init.
50
51       The request may be canceled with usb_sg_cancel, either before or after
52       usb_sg_wait is called.
53

RETURN

55       Zero for success, else a negative errno value.
56

58Kernel Hackers Manual 3.10         June 2019                    USB_SG_INIT(9)
Impressum