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USB: simplify usb_sg_init() 

This patch (as1377) simplifies the code in usb_sg_init(), without
changing its functionality.  It also removes a couple of unused fields
from the usb_sg_request structure.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern 2010-05-05 15:26:17 -04:00 committed by Greg Kroah-Hartman
parent a9914127e8
commit 0ba169aff9
2 changed files with 39 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

95
drivers/usb/core/message.c
View File

@ -371,79 +371,64 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
spin_lock_init(&io->lock);
io->dev = dev;
io->pipe = pipe;
io->sg = sg;
io->nents = nents;
io->entries = nents;
if (dev->bus->sg_tablesize > 0) {
use_sg = true;
io->entries = 1;
} else {
use_sg = false;
io->entries = nents;
}
/* initialize all the urbs we'll use */
if (dev->bus->sg_tablesize > 0) {
io->urbs = kmalloc(sizeof *io->urbs, mem_flags);
use_sg = true;
} else {
io->urbs = kmalloc(io->entries * sizeof *io->urbs, mem_flags);
use_sg = false;
}
io->urbs = kmalloc(io->entries * sizeof *io->urbs, mem_flags);
if (!io->urbs)
goto nomem;
urb_flags = 0;
urb_flags = URB_NO_INTERRUPT;
if (usb_pipein(pipe))
urb_flags |= URB_SHORT_NOT_OK;
if (use_sg) {
io->urbs[0] = usb_alloc_urb(0, mem_flags);
if (!io->urbs[0]) {
io->entries = 0;
for_each_sg(sg, sg, io->entries, i) {
struct urb *urb;
unsigned len;
urb = usb_alloc_urb(0, mem_flags);
if (!urb) {
io->entries = i;
goto nomem;
}
io->urbs[i] = urb;
io->urbs[0]->dev = NULL;
io->urbs[0]->pipe = pipe;
io->urbs[0]->interval = period;
io->urbs[0]->transfer_flags = urb_flags;
urb->dev = NULL;
urb->pipe = pipe;
urb->interval = period;
urb->transfer_flags = urb_flags;
urb->complete = sg_complete;
urb->context = io;
urb->sg = sg;
io->urbs[0]->complete = sg_complete;
io->urbs[0]->context = io;
if (use_sg) {
/* There is no single transfer buffer */
urb->transfer_buffer = NULL;
urb->num_sgs = nents;
/* A length of zero means transfer the whole sg list */
io->urbs[0]->transfer_buffer_length = length;
if (length == 0) {
for_each_sg(sg, sg, io->entries, i) {
io->urbs[0]->transfer_buffer_length +=
sg->length;
/* A length of zero means transfer the whole sg list */
len = length;
if (len == 0) {
for_each_sg(sg, sg, nents, i)
len += sg->length;
}
}
io->urbs[0]->sg = sg;
io->urbs[0]->num_sgs = io->entries;
io->entries = 1;
} else {
urb_flags |= URB_NO_INTERRUPT;
for_each_sg(sg, sg, io->entries, i) {
unsigned len;
io->urbs[i] = usb_alloc_urb(0, mem_flags);
if (!io->urbs[i]) {
io->entries = i;
goto nomem;
}
io->urbs[i]->dev = NULL;
io->urbs[i]->pipe = pipe;
io->urbs[i]->interval = period;
io->urbs[i]->transfer_flags = urb_flags;
io->urbs[i]->complete = sg_complete;
io->urbs[i]->context = io;
} else {
/*
* Some systems can't use DMA; they use PIO instead.
* For their sakes, transfer_buffer is set whenever
* possible.
*/
if (!PageHighMem(sg_page(sg)))
io->urbs[i]->transfer_buffer = sg_virt(sg);
urb->transfer_buffer = sg_virt(sg);
else
io->urbs[i]->transfer_buffer = NULL;
urb->transfer_buffer = NULL;
len = sg->length;
if (length) {
@ -452,12 +437,10 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev,
if (length == 0)
io->entries = i + 1;
}
io->urbs[i]->transfer_buffer_length = len;
io->urbs[i]->sg = sg;
}
io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
urb->transfer_buffer_length = len;
}
io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT;
/* transaction state */
io->count = io->entries;

2
include/linux/usb.h
View File

@ -1469,8 +1469,6 @@ struct usb_sg_request {
struct usb_device *dev;
int pipe;
struct scatterlist *sg;
int nents;
int entries;
struct urb **urbs;