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scsi: do not call transfer_data after canceling a request

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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 <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Paolo Bonzini 2011-10-25 12:53:33 +02:00 committed by Kevin Wolf
parent 63db0f0eee
commit e88c591d63
3 changed files with 21 additions and 4 deletions
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23
hw/scsi-bus.c
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@ -1107,8 +1107,12 @@ void scsi_req_continue(SCSIRequest *req)
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_complete(SCSIRequest *req, int status)
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_cancel(SCSIRequest *req)
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)

1
hw/scsi.h
View File

@ -51,6 +51,7 @@ struct SCSIRequest {
uint8_t sense[SCSI_SENSE_BUF_SIZE];
uint32_t sense_len;
bool enqueued;
bool io_canceled;
void *hba_private;
QTAILQ_ENTRY(SCSIRequest) next;
};

1
trace-events
View File

@ -278,6 +278,7 @@ usb_host_claim_port(int bus, int hub, int port) "bus %d, hub addr %d, port %d"
# 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"