scsi: prepare migration code for usb-storage support

usb-storage can't handle requests in one go as the data transfer can be
splitted into lots of usb packets.  Because of that there can be
normal in-flight requests at savevm time and we need to handle that.
With other scsi hba's this happens only in case i/o is stopped due to
errors and there are pending requests which need to be restarted
(req->retry = true).

So, first we need to save req->retry and then handle the req->retry =
false case.  Write requests are handled fine already.  For read requests
we have to save the buffer as we will not restart the request (and thus
not refill the buffer) on the target host.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
master
Gerd Hoffmann 2012-05-16 14:20:03 +02:00
parent 973002c114
commit 18eef3bc4e
2 changed files with 18 additions and 6 deletions

View File

@ -1507,10 +1507,9 @@ static void put_scsi_requests(QEMUFile *f, void *pv, size_t size)
QTAILQ_FOREACH(req, &s->requests, next) {
assert(!req->io_canceled);
assert(req->status == -1);
assert(req->retry);
assert(req->enqueued);
qemu_put_sbyte(f, 1);
qemu_put_sbyte(f, req->retry ? 1 : 2);
qemu_put_buffer(f, req->cmd.buf, sizeof(req->cmd.buf));
qemu_put_be32s(f, &req->tag);
qemu_put_be32s(f, &req->lun);
@ -1528,8 +1527,9 @@ static int get_scsi_requests(QEMUFile *f, void *pv, size_t size)
{
SCSIDevice *s = pv;
SCSIBus *bus = DO_UPCAST(SCSIBus, qbus, s->qdev.parent_bus);
int8_t sbyte;
while (qemu_get_sbyte(f)) {
while ((sbyte = qemu_get_sbyte(f)) > 0) {
uint8_t buf[SCSI_CMD_BUF_SIZE];
uint32_t tag;
uint32_t lun;
@ -1539,6 +1539,7 @@ static int get_scsi_requests(QEMUFile *f, void *pv, size_t size)
qemu_get_be32s(f, &tag);
qemu_get_be32s(f, &lun);
req = scsi_req_new(s, tag, lun, buf, NULL);
req->retry = (sbyte == 1);
if (bus->info->load_request) {
req->hba_private = bus->info->load_request(f, req);
}
@ -1547,7 +1548,6 @@ static int get_scsi_requests(QEMUFile *f, void *pv, size_t size)
}
/* Just restart it later. */
req->retry = true;
scsi_req_enqueue_internal(req);
/* At this point, the request will be kept alive by the reference

View File

@ -132,8 +132,14 @@ static void scsi_disk_save_request(QEMUFile *f, SCSIRequest *req)
qemu_put_be64s(f, &r->sector);
qemu_put_be32s(f, &r->sector_count);
qemu_put_be32s(f, &r->buflen);
if (r->buflen && r->req.cmd.mode == SCSI_XFER_TO_DEV) {
qemu_put_buffer(f, r->iov.iov_base, r->iov.iov_len);
if (r->buflen) {
if (r->req.cmd.mode == SCSI_XFER_TO_DEV) {
qemu_put_buffer(f, r->iov.iov_base, r->iov.iov_len);
} else if (!req->retry) {
uint32_t len = r->iov.iov_len;
qemu_put_be32s(f, &len);
qemu_put_buffer(f, r->iov.iov_base, r->iov.iov_len);
}
}
}
@ -148,6 +154,12 @@ static void scsi_disk_load_request(QEMUFile *f, SCSIRequest *req)
scsi_init_iovec(r, r->buflen);
if (r->req.cmd.mode == SCSI_XFER_TO_DEV) {
qemu_get_buffer(f, r->iov.iov_base, r->iov.iov_len);
} else if (!r->req.retry) {
uint32_t len;
qemu_get_be32s(f, &len);
r->iov.iov_len = len;
assert(r->iov.iov_len <= r->buflen);
qemu_get_buffer(f, r->iov.iov_base, r->iov.iov_len);
}
}