scsi: introduce SCSIBusOps

There are more operations than a SCSI bus can handle, besides completing
commands.  One example, which this series will introduce, is cleaning up
after a request is cancelled.

More long term, a "SCSI bus" can represent the LUNs attached to a
target; in this case, while all commands will ultimately reach a logical
unit, it is the target who is in charge of answering REPORT LUNs.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>

hw/esp.c

@@ -714,6 +714,10 @@ void esp_init(target_phys_addr_t espaddr, int it_shift,
     *dma_enable = qdev_get_gpio_in(dev, 1);
 }
 
+static const struct SCSIBusOps esp_scsi_ops = {
+    .complete = esp_command_complete
+};
+
 static int esp_init1(SysBusDevice *dev)
 {
     ESPState *s = FROM_SYSBUS(ESPState, dev);
@@ -728,7 +732,7 @@ static int esp_init1(SysBusDevice *dev)
 
     qdev_init_gpio_in(&dev->qdev, esp_gpio_demux, 2);
 
-    scsi_bus_new(&s->bus, &dev->qdev, 0, ESP_MAX_DEVS, esp_command_complete);
+    scsi_bus_new(&s->bus, &dev->qdev, 0, ESP_MAX_DEVS, &esp_scsi_ops);
     return scsi_bus_legacy_handle_cmdline(&s->bus);
 }
 

hw/lsi53c895a.c

@@ -2205,6 +2205,10 @@ static int lsi_scsi_uninit(PCIDevice *d)
     return 0;
 }
 
+static const struct SCSIBusOps lsi_scsi_ops = {
+    .complete = lsi_command_complete
+};
+
 static int lsi_scsi_init(PCIDevice *dev)
 {
     LSIState *s = DO_UPCAST(LSIState, dev, dev);
@@ -2241,7 +2245,7 @@ static int lsi_scsi_init(PCIDevice *dev)
                            PCI_BASE_ADDRESS_SPACE_MEMORY, lsi_ram_mapfunc);
     QTAILQ_INIT(&s->queue);
 
-    scsi_bus_new(&s->bus, &dev->qdev, 1, LSI_MAX_DEVS, lsi_command_complete);
+    scsi_bus_new(&s->bus, &dev->qdev, 1, LSI_MAX_DEVS, &lsi_scsi_ops);
     if (!dev->qdev.hotplugged) {
         return scsi_bus_legacy_handle_cmdline(&s->bus);
     }

hw/scsi-bus.c

@@ -21,13 +21,13 @@ static int next_scsi_bus;
 
 /* Create a scsi bus, and attach devices to it.  */
 void scsi_bus_new(SCSIBus *bus, DeviceState *host, int tcq, int ndev,
-                  scsi_completionfn complete)
+                  const SCSIBusOps *ops)
 {
     qbus_create_inplace(&bus->qbus, &scsi_bus_info, host, NULL);
     bus->busnr = next_scsi_bus++;
     bus->tcq = tcq;
     bus->ndev = ndev;
-    bus->complete = complete;
+    bus->ops = ops;
     bus->qbus.allow_hotplug = 1;
 }
 
@@ -503,7 +503,7 @@ static const char *scsi_command_name(uint8_t cmd)
 void scsi_req_data(SCSIRequest *req, int len)
 {
     trace_scsi_req_data(req->dev->id, req->lun, req->tag, len);
-    req->bus->complete(req->bus, SCSI_REASON_DATA, req->tag, len);
+    req->bus->ops->complete(req->bus, SCSI_REASON_DATA, req->tag, len);
 }
 
 void scsi_req_print(SCSIRequest *req)
@@ -538,9 +538,9 @@ void scsi_req_complete(SCSIRequest *req)
 {
     assert(req->status != -1);
     scsi_req_dequeue(req);
-    req->bus->complete(req->bus, SCSI_REASON_DONE,
-                       req->tag,
-                       req->status);
+    req->bus->ops->complete(req->bus, SCSI_REASON_DONE,
+                            req->tag,
+                            req->status);
 }
 
 static char *scsibus_get_fw_dev_path(DeviceState *dev)

hw/scsi-generic.c

@@ -335,7 +335,7 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
         s->senselen = 7;
         s->driver_status = SG_ERR_DRIVER_SENSE;
         bus = scsi_bus_from_device(d);
-        bus->complete(bus, SCSI_REASON_DONE, tag, CHECK_CONDITION);
+        bus->ops->complete(bus, SCSI_REASON_DONE, tag, CHECK_CONDITION);
         return 0;
     }
 

hw/scsi.h

@@ -16,10 +16,9 @@ enum scsi_reason {
 };
 
 typedef struct SCSIBus SCSIBus;
+typedef struct SCSIBusOps SCSIBusOps;
 typedef struct SCSIDevice SCSIDevice;
 typedef struct SCSIDeviceInfo SCSIDeviceInfo;
-typedef void (*scsi_completionfn)(SCSIBus *bus, int reason, uint32_t tag,
-                                  uint32_t arg);
 
 enum SCSIXferMode {
     SCSI_XFER_NONE,      /*  TEST_UNIT_READY, ...            */
@@ -74,20 +73,22 @@ struct SCSIDeviceInfo {
     uint8_t *(*get_buf)(SCSIDevice *s, uint32_t tag);
 };
 
-typedef void (*SCSIAttachFn)(DeviceState *host, BlockDriverState *bdrv,
-              int unit);
+struct SCSIBusOps {
+    void (*complete)(SCSIBus *bus, int reason, uint32_t tag, uint32_t arg);
+};
+
 struct SCSIBus {
     BusState qbus;
     int busnr;
 
     int tcq, ndev;
-    scsi_completionfn complete;
+    const SCSIBusOps *ops;
 
     SCSIDevice *devs[MAX_SCSI_DEVS];
 };
 
 void scsi_bus_new(SCSIBus *bus, DeviceState *host, int tcq, int ndev,
-                  scsi_completionfn complete);
+                  const SCSIBusOps *ops);
 void scsi_qdev_register(SCSIDeviceInfo *info);
 
 static inline SCSIBus *scsi_bus_from_device(SCSIDevice *d)

hw/spapr_vscsi.c

@@ -907,6 +907,10 @@ static int vscsi_do_crq(struct VIOsPAPRDevice *dev, uint8_t *crq_data)
     return 0;
 }
 
+static const struct SCSIBusOps vscsi_scsi_ops = {
+    .complete = vscsi_command_complete
+};
+
 static int spapr_vscsi_init(VIOsPAPRDevice *dev)
 {
     VSCSIState *s = DO_UPCAST(VSCSIState, vdev, dev);
@@ -923,7 +927,7 @@ static int spapr_vscsi_init(VIOsPAPRDevice *dev)
     dev->crq.SendFunc = vscsi_do_crq;
 
     scsi_bus_new(&s->bus, &dev->qdev, 1, VSCSI_REQ_LIMIT,
-                 vscsi_command_complete);
+                 &vscsi_scsi_ops);
     if (!dev->qdev.hotplugged) {
         scsi_bus_legacy_handle_cmdline(&s->bus);
     }

hw/usb-msd.c

@@ -487,6 +487,10 @@ static void usb_msd_password_cb(void *opaque, int err)
         qdev_unplug(&s->dev.qdev);
 }
 
+static const struct SCSIBusOps usb_msd_scsi_ops = {
+    .complete = usb_msd_command_complete
+};
+
 static int usb_msd_initfn(USBDevice *dev)
 {
     MSDState *s = DO_UPCAST(MSDState, dev, dev);
@@ -516,7 +520,7 @@ static int usb_msd_initfn(USBDevice *dev)
     }
 
     usb_desc_init(dev);
-    scsi_bus_new(&s->bus, &s->dev.qdev, 0, 1, usb_msd_command_complete);
+    scsi_bus_new(&s->bus, &s->dev.qdev, 0, 1, &usb_msd_scsi_ops);
     s->scsi_dev = scsi_bus_legacy_add_drive(&s->bus, bs, 0, !!s->removable);
     if (!s->scsi_dev) {
         return -1;