scsi: qedi: Complete TMF works before disconnect

We need to make sure that abort and reset completion work has completed
before ep_disconnect returns. After ep_disconnect we can't manipulate
cmds because libiscsi will call conn_stop and take onwership.

We are trying to make sure abort work and reset completion work has
completed before we do the cmd clean up in ep_disconnect. The problem is
that:

 1. the work function sets the QEDI_CONN_FW_CLEANUP bit, so if the work was
    still pending we would not see the bit set. We need to do this before
    the work is queued.

 2. If we had multiple works queued then we could break from the loop in
    qedi_ep_disconnect early because when abort work 1 completes it could
    clear QEDI_CONN_FW_CLEANUP. qedi_ep_disconnect could then see that
    before work 2 has run.

 3. A TMF reset completion work could run after ep_disconnect starts
    cleaning up cmds via qedi_clearsq. ep_disconnect's call to qedi_clearsq
    -> qedi_cleanup_all_io would might think it's done cleaning up cmds,
    but the reset completion work could still be running. We then return
    from ep_disconnect while still doing cleanup.

This replaces the bit with a counter to track the number of queued TMF
works, and adds a bool to prevent new works from starting from the
completion path once a ep_disconnect starts.

Link: https://lore.kernel.org/r/20210525181821.7617-28-michael.christie@oracle.com


Reviewed-by: Manish Rangankar <mrangankar@marvell.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>