Most device models have a simple lifecycle for the hba_private field
and they can free it when a request is completed or cancelled.
However, in some cases it may be simpler to tie the lifetime
of hba_private to that of the included SCSIRequest. This patch
adds a free_request callback to SCSIBusInfo that lets an HBA
device model do exactly that.
Normally, device models use req->hba_private == NULL to flag requests
that have been completed already. Device models that use free_request
will still need to track this using a flag. This is the reason why
"converting" existing HBAs to use free_request adds complexity and
makes little sense. It is simply an additional convenience that is
provided by the SCSI layer. USB-attached storage will be the first
user.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
SCSIRequest *scsi_req_ref(SCSIRequest *req)
{
+ assert(req->refcount > 0);
req->refcount++;
return req;
}
{
assert(req->refcount > 0);
if (--req->refcount == 0) {
+ SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, req->dev->qdev.parent_bus);
+ if (bus->info->free_request && req->hba_private) {
+ bus->info->free_request(bus, req->hba_private);
+ }
if (req->ops->free_req) {
req->ops->free_req(req);
}
void (*save_request)(QEMUFile *f, SCSIRequest *req);
void *(*load_request)(QEMUFile *f, SCSIRequest *req);
+ void (*free_request)(SCSIBus *bus, void *priv);
};
#define TYPE_SCSI_BUS "SCSI"