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, 20 insertions, 31 deletions

diff --git a/hw/usb/dev-storage.c b/hw/usb/dev-storage.c
index e732191a26..50af97109b 100644
--- a/hw/usb/dev-storage.c
+++ b/hw/usb/dev-storage.c
@@ -215,7 +215,7 @@ static const USBDesc desc = {
 static void usb_msd_copy_data(MSDState *s, USBPacket *p)
 {
     uint32_t len;
-    len = p->iov.size - p->result;
+    len = p->iov.size - p->actual_length;
     if (len > s->scsi_len)
         len = s->scsi_len;
     usb_packet_copy(p, scsi_req_get_buf(s->req) + s->scsi_off, len);
@@ -263,7 +263,8 @@ static void usb_msd_transfer_data(SCSIRequest *req, uint32_t len)
     if (p) {
         usb_msd_copy_data(s, p);
         p = s->packet;
-        if (p && p->result == p->iov.size) {
+        if (p && p->actual_length == p->iov.size) {
+            p->status = USB_RET_SUCCESS; /* Clear previous ASYNC status */
             usb_msd_packet_complete(s);
         }
     }
@@ -292,7 +293,7 @@ static void usb_msd_command_complete(SCSIRequest *req, uint32_t status, size_t r
             s->mode = USB_MSDM_CBW;
         } else {
             if (s->data_len) {
-                int len = (p->iov.size - p->result);
+                int len = (p->iov.size - p->actual_length);
                 usb_packet_skip(p, len);
                 s->data_len -= len;
             }
@@ -300,6 +301,7 @@ static void usb_msd_command_complete(SCSIRequest *req, uint32_t status, size_t r
                 s->mode = USB_MSDM_CSW;
             }
         }
+        p->status = USB_RET_SUCCESS; /* Clear previous ASYNC status */
         usb_msd_packet_complete(s);
     } else if (s->data_len == 0) {
         s->mode = USB_MSDM_CSW;
@@ -330,14 +332,14 @@ static void usb_msd_handle_reset(USBDevice *dev)
     assert(s->req == NULL);
 
     if (s->packet) {
-        s->packet->result = USB_RET_STALL;
+        s->packet->status = USB_RET_STALL;
         usb_msd_packet_complete(s);
     }
 
     s->mode = USB_MSDM_CBW;
 }
 
-static int usb_msd_handle_control(USBDevice *dev, USBPacket *p,
+static void usb_msd_handle_control(USBDevice *dev, USBPacket *p,
                int request, int value, int index, int length, uint8_t *data)
 {
     MSDState *s = (MSDState *)dev;
@@ -345,29 +347,25 @@ static int usb_msd_handle_control(USBDevice *dev, USBPacket *p,
 
     ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
-        return ret;
+        return;
     }
 
-    ret = 0;
     switch (request) {
     case EndpointOutRequest | USB_REQ_CLEAR_FEATURE:
-        ret = 0;
         break;
         /* Class specific requests.  */
     case ClassInterfaceOutRequest | MassStorageReset:
         /* Reset state ready for the next CBW.  */
         s->mode = USB_MSDM_CBW;
-        ret = 0;
         break;
     case ClassInterfaceRequest | GetMaxLun:
         data[0] = 0;
-        ret = 1;
+        p->actual_length = 1;
         break;
     default:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-    return ret;
 }
 
 static void usb_msd_cancel_io(USBDevice *dev, USBPacket *p)
@@ -382,11 +380,10 @@ static void usb_msd_cancel_io(USBDevice *dev, USBPacket *p)
     }
 }
 
-static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
+static void usb_msd_handle_data(USBDevice *dev, USBPacket *p)
 {
     MSDState *s = (MSDState *)dev;
     uint32_t tag;
-    int ret = 0;
     struct usb_msd_cbw cbw;
     uint8_t devep = p->ep->nr;
 
@@ -433,7 +430,6 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             if (s->req && s->req->cmd.xfer != SCSI_XFER_NONE) {
                 scsi_req_continue(s->req);
             }
-            ret = p->result;
             break;
 
         case USB_MSDM_DATAOUT:
@@ -446,7 +442,7 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                 usb_msd_copy_data(s, p);
             }
             if (le32_to_cpu(s->csw.residue)) {
-                int len = p->iov.size - p->result;
+                int len = p->iov.size - p->actual_length;
                 if (len) {
                     usb_packet_skip(p, len);
                     s->data_len -= len;
@@ -455,12 +451,10 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                     }
                 }
             }
-            if (p->result < p->iov.size) {
+            if (p->actual_length < p->iov.size) {
                 DPRINTF("Deferring packet %p [wait data-out]\n", p);
                 s->packet = p;
-                ret = USB_RET_ASYNC;
-            } else {
-                ret = p->result;
+                p->status = USB_RET_ASYNC;
             }
             break;
 
@@ -481,7 +475,7 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             }
             /* Waiting for SCSI write to complete.  */
             s->packet = p;
-            ret = USB_RET_ASYNC;
+            p->status = USB_RET_ASYNC;
             break;
 
         case USB_MSDM_CSW:
@@ -493,11 +487,10 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                 /* still in flight */
                 DPRINTF("Deferring packet %p [wait status]\n", p);
                 s->packet = p;
-                ret = USB_RET_ASYNC;
+                p->status = USB_RET_ASYNC;
             } else {
                 usb_msd_send_status(s, p);
                 s->mode = USB_MSDM_CBW;
-                ret = 13;
             }
             break;
 
@@ -508,7 +501,7 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                 usb_msd_copy_data(s, p);
             }
             if (le32_to_cpu(s->csw.residue)) {
-                int len = p->iov.size - p->result;
+                int len = p->iov.size - p->actual_length;
                 if (len) {
                     usb_packet_skip(p, len);
                     s->data_len -= len;
@@ -517,12 +510,10 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                     }
                 }
             }
-            if (p->result < p->iov.size) {
+            if (p->actual_length < p->iov.size) {
                 DPRINTF("Deferring packet %p [wait data-in]\n", p);
                 s->packet = p;
-                ret = USB_RET_ASYNC;
-            } else {
-                ret = p->result;
+                p->status = USB_RET_ASYNC;
             }
             break;
 
@@ -535,11 +526,9 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
     default:
         DPRINTF("Bad token\n");
     fail:
-        ret = USB_RET_STALL;
+        p->status = USB_RET_STALL;
         break;
     }
-
-    return ret;
 }
 
 static void usb_msd_password_cb(void *opaque, int err)