[Qemu-devel] [PATCH 2/2] uas: use scsi req refcounting + free_request callback

[Gerd Hoffmann <kraxel@redhat.com>]

With the new free_request callback for SCSIBusInfo we can use scsi
request refcounting instead of our own for the uas request lifecycle.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/usb/dev-uas.c |   33 ++++++++++-----------------------
 1 files changed, 10 insertions(+), 23 deletions(-)

diff --git a/hw/usb/dev-uas.c b/hw/usb/dev-uas.c
index 21fc80e..9b02ff4 100644
--- a/hw/usb/dev-uas.c
+++ b/hw/usb/dev-uas.c
@@ -123,11 +123,11 @@ struct UASRequest {
     USBPacket    *data;
     bool         data_async;
     bool         active;
+    bool         complete;
     uint32_t     buf_off;
     uint32_t     buf_size;
     uint32_t     data_off;
     uint32_t     data_size;
-    uint32_t     refcount;
     QTAILQ_ENTRY(UASRequest)  next;
 };
 
@@ -381,7 +381,7 @@ static void usb_uas_start_next_transfer(UASDevice *uas)
     UASRequest *req;
 
     QTAILQ_FOREACH(req, &uas->requests, next) {
-        if (req->active) {
+        if (req->active || req->complete) {
             continue;
         }
         if (req->req->cmd.mode == SCSI_XFER_FROM_DEV && uas->datain == NULL) {
@@ -408,12 +408,12 @@ static UASRequest *usb_uas_alloc_request(UASDevice *uas, uas_ui *ui)
     req->tag = be16_to_cpu(ui->hdr.tag);
     req->lun = be64_to_cpu(ui->command.lun);
     req->dev = usb_uas_get_dev(req->uas, req->lun);
-    req->refcount = 1;
     return req;
 }
 
-static void usb_uas_release_request(UASRequest *req)
+static void usb_uas_scsi_free_request(SCSIBus *bus, void *priv)
 {
+    UASRequest *req = priv;
     UASDevice *uas = req->uas;
 
     if (req == uas->datain) {
@@ -438,19 +438,6 @@ static UASRequest *usb_uas_find_request(UASDevice *uas, uint16_t tag)
     return NULL;
 }
 
-static void usb_uas_ref_request(UASRequest *req)
-{
-    req->refcount++;
-}
-
-static void usb_uas_unref_request(UASRequest *req)
-{
-    req->refcount--;
-    if (req->refcount == 0) {
-        usb_uas_release_request(req);
-    }
-}
-
 static void usb_uas_scsi_transfer_data(SCSIRequest *r, uint32_t len)
 {
     UASRequest *req = r->hba_private;
@@ -472,13 +459,12 @@ static void usb_uas_scsi_command_complete(SCSIRequest *r,
     UASDevice *uas = req->uas;
 
     trace_usb_uas_scsi_complete(req->uas->dev.addr, req->tag, status, resid);
+    req->complete = true;
     if (req->data) {
         usb_uas_complete_data_packet(req);
     }
     usb_uas_queue_sense(req, status);
     scsi_req_unref(req->req);
-    req->req = NULL;
-    usb_uas_unref_request(req);
     usb_uas_start_next_transfer(uas);
 }
 
@@ -487,7 +473,7 @@ static void usb_uas_scsi_request_cancelled(SCSIRequest *r)
     UASRequest *req = r->hba_private;
 
     /* FIXME: queue notification to status pipe? */
-    usb_uas_unref_request(req);
+    scsi_req_unref(req->req);
 }
 
 static const struct SCSIBusInfo usb_uas_scsi_info = {
@@ -498,6 +484,7 @@ static const struct SCSIBusInfo usb_uas_scsi_info = {
     .transfer_data = usb_uas_scsi_transfer_data,
     .complete = usb_uas_scsi_command_complete,
     .cancel = usb_uas_scsi_request_cancelled,
+    .free_request = usb_uas_scsi_free_request,
 };
 
 /* --------------------------------------------------------------------- */
@@ -706,17 +693,17 @@ static int usb_uas_handle_data(USBDevice *dev, USBPacket *p)
             ret = USB_RET_STALL;
             break;
         }
-        usb_uas_ref_request(req);
+        scsi_req_ref(req->req);
         req->data = p;
         usb_uas_copy_data(req);
-        if (p->result == p->iov.size || req->req == NULL) {
+        if (p->result == p->iov.size || req->complete) {
             req->data = NULL;
             ret = p->result;
         } else {
             req->data_async = true;
             ret = USB_RET_ASYNC;
         }
-        usb_uas_unref_request(req);
+        scsi_req_unref(req->req);
         usb_uas_start_next_transfer(uas);
         break;
     default:
-- 
1.7.1