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, 5 insertions, 3 deletions

diff --git a/hw/usb-hub.c b/hw/usb-hub.c
index b49a2fe..c49c547 100644
--- a/hw/usb-hub.c
+++ b/hw/usb-hub.c
@@ -394,11 +394,12 @@ static int usb_hub_handle_data(USBDevice *dev, USBPacket *p)
         if (p->devep == 1) {
             USBHubPort *port;
             unsigned int status;
+            uint8_t buf[4];
             int i, n;
             n = (NUM_PORTS + 1 + 7) / 8;
-            if (p->len == 1) { /* FreeBSD workaround */
+            if (p->iov.size == 1) { /* FreeBSD workaround */
                 n = 1;
-            } else if (n > p->len) {
+            } else if (n > p->iov.size) {
                 return USB_RET_BABBLE;
             }
             status = 0;
@@ -409,8 +410,9 @@ static int usb_hub_handle_data(USBDevice *dev, USBPacket *p)
             }
             if (status != 0) {
                 for(i = 0; i < n; i++) {
-                    p->data[i] = status >> (8 * i);
+                    buf[i] = status >> (8 * i);
                 }
+                usb_packet_copy(p, buf, n);
                 ret = n;
             } else {
                 ret = USB_RET_NAK; /* usb11 11.13.1 */