1USB_SG_INIT(9)                   USB Core APIs                  USB_SG_INIT(9)
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NAME

6       usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request
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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);
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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,
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19       dev
20           the usb device that will send or receive the data
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22       pipe
23           endpoint “pipe” used to transfer the data
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25       period
26           polling rate for interrupt endpoints, in frames or (for high speed
27           endpoints) microframes; ignored for bulk
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29       sg
30           scatterlist entries
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32       nents
33           how many entries in the scatterlist
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35       length
36           how many bytes to send from the scatterlist, or zero to send every
37           byte identified in the list.
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39       mem_flags
40           SLAB_* flags affecting memory allocations in this call
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DESCRIPTION

43       Returns zero for success, else a negative errno value. This initializes
44       a scatter/gather request, allocating resources such as I/O mappings and
45       urb memory (except maybe memory used by USB controller drivers).
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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.
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51       The request may be canceled with usb_sg_cancel, either before or after
52       usb_sg_wait is called.
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55Kernel Hackers Manual 2.6.         June 2019                    USB_SG_INIT(9)
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