Commit 3daa4107 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

scsi: revert change to scsi_req_cancel_async and add assertions 



Fam Zheng noticed that the change in commit 36896bff ("scsi: always call
notifier on async cancellation", 2015-12-16) could cause a leak of
the request; scsi_req_cancel_async now calls scsi_req_ref
multiple times for multiple cancellations, but there is only
one call to scsi_req_cancel_complete.

So revert the patch and instead assert that the problematic case (a call
to scsi_req_cancel_async after the aiocb has been completed) cannot
happen.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 5a57acb6

hw/scsi/scsi-bus.c

+11 −0
Original line number Diff line number Diff line
@@ -1759,6 +1759,15 @@ void scsi_req_cancel_async(SCSIRequest *req, Notifier *notifier) 
    if (notifier) {

        notifier_list_add(&req->cancel_notifiers, notifier);

    }

    if (req->io_canceled) {

        /* A blk_aio_cancel_async is pending; when it finishes,

         * scsi_req_cancel_complete will be called and will

         * call the notifier we just added.  Just wait for that.

         */

        assert(req->aiocb);

        return;

    }

    /* Dropped in scsi_req_cancel_complete.  */

    scsi_req_ref(req);

    scsi_req_dequeue(req);

    req->io_canceled = true;
@@ -1775,6 +1784,8 @@ void scsi_req_cancel(SCSIRequest *req) 
    if (!req->enqueued) {

        return;

    }

    assert(!req->io_canceled);

    /* Dropped in scsi_req_cancel_complete.  */

    scsi_req_ref(req);

    scsi_req_dequeue(req);

    req->io_canceled = true;