usb: split packet result into actual_length + status

Since with the ehci and xhci controllers a single packet can be larger
then maxpacketsize, it is possible for the result of a single packet
to be both having transferred some data as well as the transfer to have
an error.

An example would be an input transfer from a bulk endpoint successfully
receiving 1 or more maxpacketsize packets from the device, followed
by a packet signalling halt.

While already touching all the devices and controllers handle_packet /
handle_data / handle_control code, also change the return type of
these functions to void, solely storing the status in the packet. To
make the code paths for regular versus async packet handling more
uniform.

This patch unfortunately is somewhat invasive, since makeing the qemu
usb core deal with this requires changes everywhere. This patch only
prepares the usb core for this, all the hcd / device changes are done
in such a way that there are no functional changes.

This patch has been tested with uhci and ehci hcds, together with usb-audio,
usb-hid and usb-storage devices, as well as with usb-redir redirection
with a wide variety of real devices.

Note that there is usually no need to directly set packet->actual_length
form devices handle_data callback, as that is done by usb_packet_copy()

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 16 insertions, 20 deletions

diff --git a/hw/usb/dev-uas.c b/hw/usb/dev-uas.c
index 4389380e95..a21b2ba627 100644
--- a/hw/usb/dev-uas.c
+++ b/hw/usb/dev-uas.c
@@ -256,10 +256,10 @@ static void usb_uas_send_status_bh(void *opaque)
 
     uas->status = NULL;
     usb_packet_copy(p, &st->status, st->length);
-    p->result = st->length;
     QTAILQ_REMOVE(&uas->results, st, next);
     g_free(st);
 
+    p->status = USB_RET_SUCCESS; /* Clear previous ASYNC status */
     usb_packet_complete(&uas->dev, p);
 }
 
@@ -349,6 +349,7 @@ static void usb_uas_complete_data_packet(UASRequest *req)
     p = req->data;
     req->data = NULL;
     req->data_async = false;
+    p->status = USB_RET_SUCCESS; /* Clear previous ASYNC status */
     usb_packet_complete(&req->uas->dev, p);
 }
 
@@ -357,16 +358,16 @@ static void usb_uas_copy_data(UASRequest *req)
     uint32_t length;
 
     length = MIN(req->buf_size - req->buf_off,
-                 req->data->iov.size - req->data->result);
+                 req->data->iov.size - req->data->actual_length);
     trace_usb_uas_xfer_data(req->uas->dev.addr, req->tag, length,
-                            req->data->result, req->data->iov.size,
+                            req->data->actual_length, req->data->iov.size,
                             req->buf_off, req->buf_size);
     usb_packet_copy(req->data, scsi_req_get_buf(req->req) + req->buf_off,
                     length);
     req->buf_off += length;
     req->data_off += length;
 
-    if (req->data->result == req->data->iov.size) {
+    if (req->data->actual_length == req->data->iov.size) {
         usb_uas_complete_data_packet(req);
     }
     if (req->buf_size && req->buf_off == req->buf_size) {
@@ -504,17 +505,17 @@ static void usb_uas_handle_reset(USBDevice *dev)
     }
 }
 
-static int usb_uas_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_uas_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     int ret;
 
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
     fprintf(stderr, "%s: unhandled control request\n", __func__);
-    return USB_RET_STALL;
+    p->status = USB_RET_STALL;
 }
 
 static void usb_uas_cancel_io(USBDevice *dev, USBPacket *p)
@@ -641,13 +642,13 @@ incorrect_lun:
     usb_uas_queue_response(uas, tag, UAS_RC_INCORRECT_LUN, 0);
 }
 
-static int usb_uas_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_uas_handle_data(USBDevice *dev, USBPacket *p)
 {
     UASDevice *uas = DO_UPCAST(UASDevice, dev, dev);
     uas_ui ui;
     UASStatus *st;
     UASRequest *req;
-    int length, ret = 0;
+    int length;
 
     switch (p->ep->nr) {
     case UAS_PIPE_ID_COMMAND:
@@ -656,16 +657,14 @@ static int usb_uas_handle_data(USBDevice *dev, USBPacket *p)
         switch (ui.hdr.id) {
         case UAS_UI_COMMAND:
             usb_uas_command(uas, &ui);
-            ret = length;
             break;
         case UAS_UI_TASK_MGMT:
             usb_uas_task(uas, &ui);
-            ret = length;
             break;
         default:
             fprintf(stderr, "%s: unknown command ui: id 0x%x\n",
                     __func__, ui.hdr.id);
-            ret = USB_RET_STALL;
+            p->status = USB_RET_STALL;
             break;
         }
         break;
@@ -674,11 +673,10 @@ static int usb_uas_handle_data(USBDevice *dev, USBPacket *p)
         if (st == NULL) {
             assert(uas->status == NULL);
             uas->status = p;
-            ret = USB_RET_ASYNC;
+            p->status = USB_RET_ASYNC;
             break;
         }
         usb_packet_copy(p, &st->status, st->length);
-        ret = st->length;
         QTAILQ_REMOVE(&uas->results, st, next);
         g_free(st);
         break;
@@ -687,28 +685,26 @@ static int usb_uas_handle_data(USBDevice *dev, USBPacket *p)
         req = (p->ep->nr == UAS_PIPE_ID_DATA_IN) ? uas->datain : uas->dataout;
         if (req == NULL) {
             fprintf(stderr, "%s: no inflight request\n", __func__);
-            ret = USB_RET_STALL;
+            p->status = USB_RET_STALL;
             break;
         }
         scsi_req_ref(req->req);
         req->data = p;
         usb_uas_copy_data(req);
-        if (p->result == p->iov.size || req->complete) {
+        if (p->actual_length == p->iov.size || req->complete) {
             req->data = NULL;
-            ret = p->result;
         } else {
             req->data_async = true;
-            ret = USB_RET_ASYNC;
+            p->status = USB_RET_ASYNC;
         }
         scsi_req_unref(req->req);
         usb_uas_start_next_transfer(uas);
         break;
     default:
         fprintf(stderr, "%s: invalid endpoint %d\n", __func__, p->ep->nr);
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
 static void usb_uas_handle_destroy(USBDevice *dev)