[Qemu-devel] [PATCH 33/55] scsi: remove devs array from SCSIBus

[Kevin Wolf <kwolf@redhat.com>]

From: 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, and HBAs can talk to the correct device
when there are multiple LUNs per target.

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>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/esp.c         |    8 +++++---
 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, 50 insertions(+), 52 deletions(-)

diff --git a/hw/esp.c b/hw/esp.c
index d3fb1c6..aad290f 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;
 }
 
@@ -233,10 +233,12 @@ static void do_busid_cmd(ESPState *s, uint8_t *buf, uint8_t busid)
 {
     int32_t datalen;
     int lun;
+    SCSIDevice *current_lun;
 
     trace_esp_do_busid_cmd(busid);
     lun = busid & 7;
-    s->current_req = scsi_req_new(s->current_dev, 0, lun, buf, NULL);
+    current_lun = scsi_device_find(&s->bus, s->current_dev->id, lun);
+    s->current_req = scsi_req_new(current_lun, 0, lun, buf, NULL);
     datalen = scsi_req_enqueue(s->current_req);
     s->ti_size = datalen;
     if (datalen != 0) {
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 a7cc48b..36a4198 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 33ae9b4..ea3bb08 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 {
-- 
1.7.6.4