/* Stop the current URB transfer */
void usb_stor_stop_transport(struct us_data *us)
{
US_DEBUGP("%s called\n", __func__);
/* If the state machine is blocked waiting for an URB,
* let's wake it up. The test_and_clear_bit() call
* guarantees that if a URB has just been submitted,
* it won't be cancelled more than once. */
if (test_and_clear_bit(US_FLIDX_URB_ACTIVE, &us->dflags)) {
US_DEBUGP("-- cancelling URB\n");
usb_unlink_urb(us->current_urb);
}
/* If we are waiting for a scatter-gather operation, cancel it. */
if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
US_DEBUGP("-- cancelling sg request\n");
usb_sg_cancel(&us->current_sg);
}
}
/*
* Transfer a scatter-gather list via bulk transfer
*
* This function does basically the same thing as usb_stor_bulk_transfer_buf()
* above, but it uses the usbcore scatter-gather library.
*/
static int usb_stor_bulk_transfer_sglist(struct us_data *us, unsigned int pipe,
struct scatterlist *sg, int num_sg, unsigned int length,
unsigned int *act_len)
{
int result;
/* don't submit s-g requests during abort processing */
if (test_bit(US_FLIDX_ABORTING, &us->dflags))
return USB_STOR_XFER_ERROR;
/* initialize the scatter-gather request block */
usb_stor_dbg(us, "xfer %u bytes, %d entries\n", length, num_sg);
result = usb_sg_init(&us->current_sg, us->pusb_dev, pipe, 0,
sg, num_sg, length, GFP_NOIO);
if (result) {
usb_stor_dbg(us, "usb_sg_init returned %d\n", result);
return USB_STOR_XFER_ERROR;
}
/* since the block has been initialized successfully, it's now
* okay to cancel it */
set_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
/* did an abort occur during the submission? */
if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
/* cancel the request, if it hasn't been cancelled already */
if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
usb_stor_dbg(us, "-- cancelling sg request\n");
usb_sg_cancel(&us->current_sg);
}
}
/* wait for the completion of the transfer */
usb_sg_wait(&us->current_sg);
clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
result = us->current_sg.status;
if (act_len)
*act_len = us->current_sg.bytes;
return interpret_urb_result(us, pipe, length, result,
us->current_sg.bytes);
}
static int usb_stor_bulk_transfer_sglist(struct us_data *us, unsigned int pipe,
struct scatterlist *sg, int num_sg, unsigned int length,
unsigned int *act_len)
{
int result;
if (test_bit(US_FLIDX_ABORTING, &us->dflags))
return USB_STOR_XFER_ERROR;
US_DEBUGP("%s: xfer %u bytes, %d entries\n", __func__,
length, num_sg);
result = usb_sg_init(&us->current_sg, us->pusb_dev, pipe, 0,
sg, num_sg, length, GFP_NOIO);
if (result) {
US_DEBUGP("usb_sg_init returned %d\n", result);
return USB_STOR_XFER_ERROR;
}
set_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
if (test_bit(US_FLIDX_ABORTING, &us->dflags)) {
if (test_and_clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags)) {
US_DEBUGP("-- cancelling sg request\n");
usb_sg_cancel(&us->current_sg);
}
}
usb_sg_wait(&us->current_sg);
clear_bit(US_FLIDX_SG_ACTIVE, &us->dflags);
result = us->current_sg.status;
if (act_len)
*act_len = us->current_sg.bytes;
return interpret_urb_result(us, pipe, length, result,
us->current_sg.bytes);
}
/**
* usb_sg_wait - synchronously execute scatter/gather request
* @io: request block handle, as initialized with usb_sg_init().
* some fields become accessible when this call returns.
* Context: !in_interrupt ()
*
* This function blocks until the specified I/O operation completes. It
* leverages the grouping of the related I/O requests to get good transfer
* rates, by queueing the requests. At higher speeds, such queuing can
* significantly improve USB throughput.
*
* There are three kinds of completion for this function.
* (1) success, where io->status is zero. The number of io->bytes
* transferred is as requested.
* (2) error, where io->status is a negative errno value. The number
* of io->bytes transferred before the error is usually less
* than requested, and can be nonzero.
* (3) cancelation, a type of error with status -ECONNRESET that
* is initiated by usb_sg_cancel().
*
* When this function returns, all memory allocated through usb_sg_init() or
* this call will have been freed. The request block parameter may still be
* passed to usb_sg_cancel(), or it may be freed. It could also be
* reinitialized and then reused.
*
* Data Transfer Rates:
*
* Bulk transfers are valid for full or high speed endpoints.
* The best full speed data rate is 19 packets of 64 bytes each
* per frame, or 1216 bytes per millisecond.
* The best high speed data rate is 13 packets of 512 bytes each
* per microframe, or 52 KBytes per millisecond.
*
* The reason to use interrupt transfers through this API would most likely
* be to reserve high speed bandwidth, where up to 24 KBytes per millisecond
* could be transferred. That capability is less useful for low or full
* speed interrupt endpoints, which allow at most one packet per millisecond,
* of at most 8 or 64 bytes (respectively).
*/
void usb_sg_wait (struct usb_sg_request *io)
{
int i, entries = io->entries;
/* queue the urbs. */
spin_lock_irq (&io->lock);
for (i = 0; i < entries && !io->status; i++) {
int retval;
io->urbs [i]->dev = io->dev;
retval = usb_submit_urb (io->urbs [i], SLAB_ATOMIC);
/* after we submit, let completions or cancelations fire;
* we handshake using io->status.
*/
spin_unlock_irq (&io->lock);
switch (retval) {
/* maybe we retrying will recover */
case -ENXIO: // hc didn't queue this one
case -EAGAIN:
case -ENOMEM:
io->urbs[i]->dev = NULL;
retval = 0;
i--;
yield ();
break;
/* no error? continue immediately.
*
* NOTE: to work better with UHCI (4K I/O buffer may
* need 3K of TDs) it may be good to limit how many
* URBs are queued at once; N milliseconds?
*/
case 0:
cpu_relax ();
break;
/* fail any uncompleted urbs */
default:
spin_lock_irq (&io->lock);
io->count -= entries - i;
if (io->status == -EINPROGRESS)
io->status = retval;
if (io->count == 0)
complete (&io->complete);
spin_unlock_irq (&io->lock);
io->urbs[i]->dev = NULL;
io->urbs [i]->status = retval;
dev_dbg (&io->dev->dev, "%s, submit --> %d\n",
__FUNCTION__, retval);
usb_sg_cancel (io);
}
spin_lock_irq (&io->lock);
if (retval && io->status == -ECONNRESET)
io->status = retval;
}
spin_unlock_irq (&io->lock);
/* OK, yes, this could be packaged as non-blocking.
* So could the submit loop above ... but it's easier to
* solve neither problem than to solve both!
*/
wait_for_completion (&io->complete);
sg_clean (io);
}