[Qemu-devel] [PATCH 15/35] scsi: remove devs array from SCSIBus

[Paolo Bonzini <pbonzini@redhat.com>]

Change the devs array into a linked list, and add a scsi_device_find
function to navigate the children list instead.  This lets the SCSI
bus use more complex addressing.

scsi_device_find may return another LUN on the same target if none is
found that matches exactly.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/esp.c         |    5 +++--
 hw/lsi53c895a.c  |   22 +++++++---------------
 hw/qdev.h        |    2 +-
 hw/scsi-bus.c    |   53 ++++++++++++++++++++++++++++++-----------------------
 hw/scsi.h        |    3 +--
 hw/spapr_vscsi.c |   14 ++++++--------
 6 files changed, 48 insertions(+), 51 deletions(-)

diff --git a/hw/esp.c b/hw/esp.c
index d3fb1c6..8e17005 100644
--- a/hw/esp.c
+++ b/hw/esp.c
@@ -217,7 +217,8 @@ static uint32_t get_cmd(ESPState *s, uint8_t *buf)
         s->async_len = 0;
     }
 
-    if (target >= ESP_MAX_DEVS || !s->bus.devs[target]) {
+    s->current_dev = scsi_device_find(&s->bus, target, 0);
+    if (!s->current_dev) {
         // No such drive
         s->rregs[ESP_RSTAT] = 0;
         s->rregs[ESP_RINTR] = INTR_DC;
@@ -225,7 +226,6 @@ static uint32_t get_cmd(ESPState *s, uint8_t *buf)
         esp_raise_irq(s);
         return 0;
     }
-    s->current_dev = s->bus.devs[target];
     return dmalen;
 }
 
@@ -236,6 +236,7 @@ static void do_busid_cmd(ESPState *s, uint8_t *buf, uint8_t busid)
 
     trace_esp_do_busid_cmd(busid);
     lun = busid & 7;
+    s->current_dev = scsi_device_find(&s->bus, s->current_dev->id, lun);
     s->current_req = scsi_req_new(s->current_dev, 0, lun, buf, NULL);
     datalen = scsi_req_enqueue(s->current_req);
     s->ti_size = datalen;
diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
index 4eeb496..c15f167 100644
--- a/hw/lsi53c895a.c
+++ b/hw/lsi53c895a.c
@@ -531,7 +531,7 @@ static void lsi_bad_selection(LSIState *s, uint32_t id)
 /* Initiate a SCSI layer data transfer.  */
 static void lsi_do_dma(LSIState *s, int out)
 {
-    uint32_t count, id;
+    uint32_t count;
     target_phys_addr_t addr;
     SCSIDevice *dev;
 
@@ -542,12 +542,8 @@ static void lsi_do_dma(LSIState *s, int out)
         return;
     }
 
-    id = (s->current->tag >> 8) & 0xf;
-    dev = s->bus.devs[id];
-    if (!dev) {
-        lsi_bad_selection(s, id);
-        return;
-    }
+    dev = s->current->req->dev;
+    assert(dev);
 
     count = s->dbc;
     if (count > s->current->dma_len)
@@ -771,7 +767,7 @@ static void lsi_do_command(LSIState *s)
     s->command_complete = 0;
 
     id = (s->select_tag >> 8) & 0xf;
-    dev = s->bus.devs[id];
+    dev = scsi_device_find(&s->bus, id, s->current_lun);
     if (!dev) {
         lsi_bad_selection(s, id);
         return;
@@ -1202,7 +1198,7 @@ again:
                 }
                 s->sstat0 |= LSI_SSTAT0_WOA;
                 s->scntl1 &= ~LSI_SCNTL1_IARB;
-                if (id >= LSI_MAX_DEVS || !s->bus.devs[id]) {
+                if (!scsi_device_find(&s->bus, id, 0)) {
                     lsi_bad_selection(s, id);
                     break;
                 }
@@ -1684,13 +1680,9 @@ static void lsi_reg_writeb(LSIState *s, int offset, uint8_t val)
         if (val & LSI_SCNTL1_RST) {
             if (!(s->sstat0 & LSI_SSTAT0_RST)) {
                 DeviceState *dev;
-                int id;
 
-                for (id = 0; id < LSI_MAX_DEVS; id++) {
-                    if (s->bus.devs[id]) {
-                        dev = &s->bus.devs[id]->qdev;
-                        dev->info->reset(dev);
-                    }
+                QTAILQ_FOREACH(dev, &s->bus.qbus.children, sibling) {
+                    dev->info->reset(dev);
                 }
                 s->sstat0 |= LSI_SSTAT0_RST;
                 lsi_script_scsi_interrupt(s, LSI_SIST0_RST, 0);
diff --git a/hw/qdev.h b/hw/qdev.h
index ff524cb..e5ad781 100644
--- a/hw/qdev.h
+++ b/hw/qdev.h
@@ -73,7 +73,7 @@ struct BusState {
     const char *name;
     int allow_hotplug;
     int qdev_allocated;
-    QTAILQ_HEAD(, DeviceState) children;
+    QTAILQ_HEAD(ChildrenHead, DeviceState) children;
     QLIST_ENTRY(BusState) sibling;
 };
 
diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
index d9d4e18..7104e98 100644
--- a/hw/scsi-bus.c
+++ b/hw/scsi-bus.c
@@ -37,12 +37,16 @@ static int scsi_qdev_init(DeviceState *qdev, DeviceInfo *base)
     SCSIDevice *dev = DO_UPCAST(SCSIDevice, qdev, qdev);
     SCSIDeviceInfo *info = DO_UPCAST(SCSIDeviceInfo, qdev, base);
     SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);
+    SCSIDevice *olddev;
     int rc = -1;
 
     if (dev->id == -1) {
-        for (dev->id = 0; dev->id < bus->info->ndev; dev->id++) {
-            if (bus->devs[dev->id] == NULL)
+        int id;
+        for (id = 0; id < bus->info->ndev; id++) {
+            if (!scsi_device_find(bus, id, 0)) {
+                dev->id = id;
                 break;
+            }
         }
     }
     if (dev->id >= bus->info->ndev) {
@@ -50,17 +54,14 @@ static int scsi_qdev_init(DeviceState *qdev, DeviceInfo *base)
         goto err;
     }
 
-    if (bus->devs[dev->id]) {
-        qdev_free(&bus->devs[dev->id]->qdev);
+    olddev = scsi_device_find(bus, dev->id, dev->lun);
+    if (olddev && dev->lun == olddev->lun) {
+        qdev_free(&olddev->qdev);
     }
-    bus->devs[dev->id] = dev;
 
     dev->info = info;
     QTAILQ_INIT(&dev->requests);
     rc = dev->info->init(dev);
-    if (rc != 0) {
-        bus->devs[dev->id] = NULL;
-    }
 
 err:
     return rc;
@@ -69,13 +70,10 @@ err:
 static int scsi_qdev_exit(DeviceState *qdev)
 {
     SCSIDevice *dev = DO_UPCAST(SCSIDevice, qdev, qdev);
-    SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, dev->qdev.parent_bus);
 
-    assert(bus->devs[dev->id] != NULL);
-    if (bus->devs[dev->id]->info->destroy) {
-        bus->devs[dev->id]->info->destroy(bus->devs[dev->id]);
+    if (dev->info->destroy) {
+        dev->info->destroy(dev);
     }
-    bus->devs[dev->id] = NULL;
     return 0;
 }
 
@@ -1157,19 +1155,28 @@ void scsi_device_purge_requests(SCSIDevice *sdev, SCSISense sense)
 static char *scsibus_get_fw_dev_path(DeviceState *dev)
 {
     SCSIDevice *d = DO_UPCAST(SCSIDevice, qdev, dev);
-    SCSIBus *bus = scsi_bus_from_device(d);
     char path[100];
-    int i;
 
-    for (i = 0; i < bus->info->ndev; i++) {
-        if (bus->devs[i] == d) {
-            break;
-        }
-    }
+    snprintf(path, sizeof(path), "%s@%d:%d:%d", qdev_fw_name(dev),
+             0, d->id, d->lun);
 
-    assert(i != bus->info->ndev);
+    return strdup(path);
+}
+
+SCSIDevice *scsi_device_find(SCSIBus *bus, int id, int lun)
+{
+    DeviceState *qdev;
+    SCSIDevice *target_dev = NULL;
 
-    snprintf(path, sizeof(path), "%s@%x", qdev_fw_name(dev), i);
+    QTAILQ_FOREACH_REVERSE(qdev, &bus->qbus.children, ChildrenHead, sibling) {
+        SCSIDevice *dev = DO_UPCAST(SCSIDevice, qdev, qdev);
 
-    return strdup(path);
+        if (dev->id == id) {
+            if (dev->lun == lun) {
+                return dev;
+            }
+            target_dev = dev;
+        }
+    }
+    return target_dev;
 }
diff --git a/hw/scsi.h b/hw/scsi.h
index b76c4ee..add3d2d 100644
--- a/hw/scsi.h
+++ b/hw/scsi.h
@@ -110,8 +110,6 @@ struct SCSIBus {
 
     SCSISense unit_attention;
     const SCSIBusInfo *info;
-
-    SCSIDevice *devs[MAX_SCSI_DEVS];
 };
 
 void scsi_bus_new(SCSIBus *bus, DeviceState *host, const SCSIBusInfo *info);
@@ -195,5 +193,6 @@ void scsi_req_abort(SCSIRequest *req, int status);
 void scsi_req_cancel(SCSIRequest *req);
 void scsi_device_purge_requests(SCSIDevice *sdev, SCSISense sense);
 int scsi_device_get_sense(SCSIDevice *dev, uint8_t *buf, int len, bool fixed);
+SCSIDevice *scsi_device_find(SCSIBus *bus, int target, int lun);
 
 #endif
diff --git a/hw/spapr_vscsi.c b/hw/spapr_vscsi.c
index 6c5faf2..aae845a 100644
--- a/hw/spapr_vscsi.c
+++ b/hw/spapr_vscsi.c
@@ -129,11 +129,12 @@ static void vscsi_put_req(vscsi_req *req)
     req->active = 0;
 }
 
-static void vscsi_decode_id_lun(uint64_t srp_lun, int *id, int *lun)
+static SCSIDevice *vscsi_device_find(SCSIBus *bus, uint64_t srp_lun, int *lun)
 {
     /* XXX Figure that one out properly ! This is crackpot */
-    *id = (srp_lun >> 56) & 0x7f;
+    int id = (srp_lun >> 56) & 0x7f;
     *lun = (srp_lun >> 48) & 0xff;
+    return scsi_device_find (bus, id, *lun);
 }
 
 static int vscsi_send_iu(VSCSIState *s, vscsi_req *req,
@@ -582,14 +583,11 @@ static int vscsi_queue_cmd(VSCSIState *s, vscsi_req *req)
 {
     union srp_iu *srp = &req->iu.srp;
     SCSIDevice *sdev;
-    int n, id, lun;
+    int n, lun;
 
-    vscsi_decode_id_lun(be64_to_cpu(srp->cmd.lun), &id, &lun);
-
-    /* Qemu vs. linux issue with LUNs to be sorted out ... */
-    sdev = (id < 8 && lun < 16) ? s->bus.devs[id] : NULL;
+    sdev = vscsi_device_find(&s->bus, be64_to_cpu(srp->cmd.lun), &lun);
     if (!sdev) {
-        dprintf("VSCSI: Command for id %d with no drive\n", id);
+        dprintf("VSCSI: Command for lun %08" PRIx64 " with no drive\n", be64_to_cpu(srp->cmd.lun));
         if (srp->cmd.cdb[0] == INQUIRY) {
             vscsi_inquiry_no_target(s, req);
         } else {
-- 
1.7.6