usb: use iovecs in USBPacket

Zap data pointer from USBPacket, add a QEMUIOVector instead.
Add a bunch of helper functions to manage USBPacket data.
Switch over users to the new interface.

Note that USBPacket->len was used for two purposes:  First to
pass in the buffer size and second to return the number of
transfered bytes or the status code on async transfers.  There
is a new result variable for the latter.  A new status code
was added to catch uninitialized result.

Nobody creates iovecs with more than one element (yet).
Some users are (temporarely) limited to iovecs with a single
element to keep the patch size as small as possible.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/usb-bsd.c b/usb-bsd.c
index ab8e3b7..ab84d93 100644
--- a/usb-bsd.c
+++ b/usb-bsd.c
@@ -253,9 +253,9 @@ static int usb_host_handle_data(USBDevice *dev, USBPacket *p)
     }
 
     if (p->pid == USB_TOKEN_IN)
-        ret = read(fd, p->data, p->len);
+        ret = readv(fd, p->iov.iov, p->iov.niov);
     else
-        ret = write(fd, p->data, p->len);
+        ret = writev(fd, p->iov.iov, p->iov.niov);
 
     sigprocmask(SIG_SETMASK, &old_mask, NULL);