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| author | Ming Lei <ming.lei@canonical.com> | 2013-08-08 21:48:22 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-12 11:56:16 -0700 |
| commit | bcc48f1a7a0d40ae2e5a26aff72c2b674fd8b596 (patch) | |
| tree | 887e24d1dc2f7701dae13ec2d071ee71cdddccdc /drivers/usb/core | |
| parent | 428aac8a81058e2303677a8fbf26670229e51d3a (diff) | |
| download | linux-bcc48f1a7a0d40ae2e5a26aff72c2b674fd8b596.tar.gz linux-bcc48f1a7a0d40ae2e5a26aff72c2b674fd8b596.tar.bz2 linux-bcc48f1a7a0d40ae2e5a26aff72c2b674fd8b596.zip | |
USB: introduce usb_device_no_sg_constraint() helper
Some host controllers(such as xHCI) can support building
packet from discontinuous buffers, so introduce one flag
and helper for this kind of host controllers, then the
feature can help some applications(such as usbnet) by
supporting arbitrary length of sg buffers.
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core')
| -rw-r--r-- | drivers/usb/core/urb.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c index 4e7a311ff6d7..c12bc790a6a7 100644 --- a/drivers/usb/core/urb.c +++ b/drivers/usb/core/urb.c @@ -416,7 +416,8 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) urb->iso_frame_desc[n].status = -EXDEV; urb->iso_frame_desc[n].actual_length = 0; } - } else if (dev->speed != USB_SPEED_WIRELESS && urb->num_sgs) { + } else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint && + dev->speed != USB_SPEED_WIRELESS) { struct scatterlist *sg; int i; |