scsi: Increase the number of possible devices

The SCSI parallel interface has a limit of 8 devices, but
not the SCSI stack in general. So we should be removing the
hard-coded limit and use MAX_SCSI_DEVS instead.
And we only need to scan those devices which are allocated
by the bus.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

blockdev.h

@@ -32,7 +32,7 @@ struct DriveInfo {
 };
 
 #define MAX_IDE_DEVS	2
-#define MAX_SCSI_DEVS	7
+#define MAX_SCSI_DEVS	255
 
 DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit);
 int drive_get_max_bus(BlockInterfaceType type);

hw/scsi-bus.c

@@ -108,7 +108,7 @@ int scsi_bus_legacy_handle_cmdline(SCSIBus *bus)
     int res = 0, unit;
 
     loc_push_none(&loc);
-    for (unit = 0; unit < MAX_SCSI_DEVS; unit++) {
+    for (unit = 0; unit < bus->ndev; unit++) {
         dinfo = drive_get(IF_SCSI, bus->busnr, unit);
         if (dinfo == NULL) {
             continue;

hw/scsi.h

@@ -3,6 +3,7 @@
 
 #include "qdev.h"
 #include "block.h"
+#include "blockdev.h"
 #include "block_int.h"
 
 #define SCSI_CMD_BUF_SIZE     16
@@ -86,7 +87,7 @@ struct SCSIBus {
     int tcq, ndev;
     scsi_completionfn complete;
 
-    SCSIDevice *devs[8];
+    SCSIDevice *devs[MAX_SCSI_DEVS];
 };
 
 void scsi_bus_new(SCSIBus *bus, DeviceState *host, int tcq, int ndev,