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Commit 0ba169af authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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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: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent a9914127

drivers/usb/core/message.c

+38 −55
Original line number Diff line number Diff line
@@ -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;



	/* initialize all the urbs we'll use */

	if (dev->bus->sg_tablesize > 0) {

		io->urbs = kmalloc(sizeof *io->urbs, mem_flags);

		use_sg = true;

		io->entries = 1;

	} else {

		io->urbs = kmalloc(io->entries * sizeof *io->urbs, mem_flags);

		use_sg = false;

		io->entries = nents;

	}



	/* initialize all the urbs we'll use */

	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;

			goto nomem;

		}



		io->urbs[0]->dev = NULL;

		io->urbs[0]->pipe = pipe;

		io->urbs[0]->interval = period;

		io->urbs[0]->transfer_flags = urb_flags;



		io->urbs[0]->complete = sg_complete;

		io->urbs[0]->context = io;



		/* 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;

			}

		}

		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) {

		struct urb *urb;

		unsigned len;



			io->urbs[i] = usb_alloc_urb(0, mem_flags);

			if (!io->urbs[i]) {

		urb = usb_alloc_urb(0, mem_flags);

		if (!urb) {

			io->entries = i;

			goto nomem;

		}

		io->urbs[i] = urb;



			io->urbs[i]->dev = NULL;

			io->urbs[i]->pipe = pipe;

			io->urbs[i]->interval = period;

			io->urbs[i]->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[i]->complete = sg_complete;

			io->urbs[i]->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 */

			len = length;

			if (len == 0) {

				for_each_sg(sg, sg, nents, i)

					len += sg->length;

			}

		} 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;

include/linux/usb.h

+0 −2
Original line number Diff line number Diff line
@@ -1469,8 +1469,6 @@ struct usb_sg_request { 


	struct usb_device	*dev;

	int			pipe;

	struct scatterlist	*sg;

	int			nents;



	int			entries;

	struct urb		**urbs;