scsi: do not call transfer_data after canceling a request
Otherwise, if cancellation is "faked" by the AIO layer and goes
through qemu_aio_flush, the whole request is completed synchronously
during scsi_req_cancel.
Using the enqueued flag would work here, but not in the next patches,
so I'm introducing a new io_canceled flag. That's because scsi_req_data
is a synchronous callback and the enqueued flag might be reset by the
time it returns. scsi-disk cannot unref the request until after calling
scsi_req_data.
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>
diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
index 3cf571e..dfce5fb 100644
--- a/hw/scsi-bus.c
+++ b/hw/scsi-bus.c
@@ -1107,8 +1107,12 @@
Once it completes, calling scsi_req_continue will restart I/O. */
void scsi_req_data(SCSIRequest *req, int len)
{
- trace_scsi_req_data(req->dev->id, req->lun, req->tag, len);
- req->bus->info->transfer_data(req, len);
+ if (req->io_canceled) {
+ trace_scsi_req_data_canceled(req->dev->id, req->lun, req->tag, len);
+ } else {
+ trace_scsi_req_data(req->dev->id, req->lun, req->tag, len);
+ req->bus->info->transfer_data(req, len);
+ }
}
void scsi_req_print(SCSIRequest *req)
@@ -1173,11 +1177,15 @@
void scsi_req_cancel(SCSIRequest *req)
{
- if (req->ops->cancel_io) {
- req->ops->cancel_io(req);
+ if (!req->enqueued) {
+ return;
}
scsi_req_ref(req);
scsi_req_dequeue(req);
+ req->io_canceled = true;
+ if (req->ops->cancel_io) {
+ req->ops->cancel_io(req);
+ }
if (req->bus->info->cancel) {
req->bus->info->cancel(req);
}
@@ -1186,10 +1194,17 @@
void scsi_req_abort(SCSIRequest *req, int status)
{
+ if (!req->enqueued) {
+ return;
+ }
+ scsi_req_ref(req);
+ scsi_req_dequeue(req);
+ req->io_canceled = true;
if (req->ops->cancel_io) {
req->ops->cancel_io(req);
}
scsi_req_complete(req, status);
+ scsi_req_unref(req);
}
void scsi_device_purge_requests(SCSIDevice *sdev, SCSISense sense)
diff --git a/hw/scsi.h b/hw/scsi.h
index 8ea744a..fcc3455 100644
--- a/hw/scsi.h
+++ b/hw/scsi.h
@@ -51,6 +51,7 @@
uint8_t sense[SCSI_SENSE_BUF_SIZE];
uint32_t sense_len;
bool enqueued;
+ bool io_canceled;
void *hba_private;
QTAILQ_ENTRY(SCSIRequest) next;
};
diff --git a/trace-events b/trace-events
index a888055..56443af 100644
--- a/trace-events
+++ b/trace-events
@@ -278,6 +278,7 @@
# hw/scsi-bus.c
scsi_req_alloc(int target, int lun, int tag) "target %d lun %d tag %d"
scsi_req_data(int target, int lun, int tag, int len) "target %d lun %d tag %d len %d"
+scsi_req_data_canceled(int target, int lun, int tag, int len) "target %d lun %d tag %d len %d"
scsi_req_dequeue(int target, int lun, int tag) "target %d lun %d tag %d"
scsi_req_continue(int target, int lun, int tag) "target %d lun %d tag %d"
scsi_req_parsed(int target, int lun, int tag, int cmd, int mode, int xfer) "target %d lun %d tag %d command %d dir %d length %d"
