The stall timer worker checks periodically if there is a stalled i/o
transaction. The issue with the current implementation is that the timer
is ticking also when there is no pending i/o transaction.
This patch provides a simple change that prevents rescheduling
of the delayed work when there is no pending i/o.

Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The FW supports only one pending read per host client, in order to
support  issuing of consecutive reads the driver  queues read requests
internally and send them to the firmware after pending one has
completed.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The read callback is always prepared with MTU-sized buffer and the FW
can't send more than the MTU in one message.
Checking for buffer existence and krealloc to increase receive buffer
size are redundant and may be safely discarded.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The Fixed address clients do not work with the flow control, and the
packet RX callback was allocated upon TX with anticipation of a
following RX. This won't work if the clients with unsolicited Rx. Rather
than preparing read callback upon a write we allocate one directly on
the reciev path if one doesn't exists.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Store the file associated with a client in the host client structure,
this enables dropping the special amthif client file pointer from struct
mei_device, and this is also a preparation for changing the way rx
packet allocation for fixed_address clients

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Move read cb to the completion queue if a read finds out that client
is not connected. This expedite user space reader wake on error
condition.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iamthif_current_cb was used in request cancel in amthif code.
Now a canceled request is discarded only at the end of the processing
and the variable lost its purpose and can be safely removed.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently, all requests cancelled by the user are immediately removed
from the queues. Such removal can cause unexpected behavior in the case
when a request is partially written or a  reply is received after the
request is cancelled.  To resolve this a request is always fully
processed and the result is discarded in case the request was canceled.
This completes the partial fix in commit:
9d04ee1 ("mei: amthif: discard not read messages")

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When a message is received and amthif client is not in reading state
the message is ignored and left dangling in the queue. This may happen
after one of the amthif host connections is closed w/o completing the
reading. Another client will pick up a wrong message on next read
attempt which will lead to link reset.
To prevent this the driver has to properly discard the message when
amthif client is not in reading state.

Cc: <stable@vger.kernel.org> #4.2+
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In the case when disconnection is initiated from the FW
the driver is flushing items from the write control list while
iterating over it:

mei_irq_write_handler()
    list_for_each_entry_safe(ctrl_wr_list)         <-- outer loop
         mei_cl_irq_disconnect_rsp()
             mei_cl_set_disconnected()
                 mei_io_list_flush(ctrl_wr_list)   <-- destorying list

We move the list flushing to the completion routine.

Cc: <stable@vger.kernel.org> #4.2+
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>