USB: remove uses of URB_NO_SETUP_DMA_MAP

This patch (as1350) removes all usages of coherent buffers for USB
control-request setup-packet buffers.  There's no good reason to
reserve coherent memory for these things; control requests are hardly
ever used in large quantity (the major exception is firmware
transfers, and they aren't time-critical).  Furthermore, only seven
drivers used it.  We might as well always use streaming DMA mappings
for setup-packet buffers, and remove some extra complexity from
usbcore.

The DMA-mapping portion of hcd.c is currently in flux.  A separate
patch will be submitted to remove support for URB_NO_SETUP_DMA_MAP
after everything else settles down.  The removal should go smoothly,
as by then nobody will be using it.

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
2010-03-05 15:10:17 -05:00
committed by Greg Kroah-Hartman
parent 749da5f82f
commit 0ede76fcec
13 changed files with 27 additions and 75 deletions

View File

@@ -147,11 +147,9 @@ static int usb_stor_msg_common(struct us_data *us, int timeout)
* hasn't been mapped for DMA. Yes, this is clunky, but it's
* easier than always having the caller tell us whether the
* transfer buffer has already been mapped. */
us->current_urb->transfer_flags = URB_NO_SETUP_DMA_MAP;
if (us->current_urb->transfer_buffer == us->iobuf)
us->current_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
us->current_urb->transfer_dma = us->iobuf_dma;
us->current_urb->setup_dma = us->cr_dma;
/* submit the URB */
status = usb_submit_urb(us->current_urb, GFP_NOIO);