usb storage: handle long responses

The scsi layer may return us more data than the guests wants to have.
Handle this by just ignoring the extra bytes and calling the
{read,write}_data callback to finish the request.

Seen happening in real life with some extended inquiry command.
With this patch applied the linux kernel stops reseting the device
once at boot.

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

diff --git a/hw/usb-msd.c b/hw/usb-msd.c
index 28c12dd632e497666ccb04f33a057ca97a0c53a7..729d96ccc3e562166d0187fce7103a4e44d2624c 100644 (file)
--- a/hw/usb-msd.c
+++ b/hw/usb-msd.c
@@ -187,7 +187,7 @@ static void usb_msd_copy_data(MSDState *s)
     s->usb_buf += len;
     s->scsi_buf += len;
     s->data_len -= len;
-    if (s->scsi_len == 0) {
+    if (s->scsi_len == 0 || s->data_len == 0) {
         if (s->mode == USB_MSDM_DATAIN) {
             s->scsi_dev->info->read_data(s->scsi_dev, s->tag);
         } else if (s->mode == USB_MSDM_DATAOUT) {
@@ -434,7 +434,7 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             break;
 
         case USB_MSDM_DATAIN:
-            DPRINTF("Data in %d/%d\n", len, s->data_len);
+            DPRINTF("Data in %d/%d, scsi_len %d\n", len, s->data_len, s->scsi_len);
             if (len > s->data_len)
                 len = s->data_len;
             s->usb_buf = data;