tree 3e0e0002e405204bb78dc7e7e9444e0adab56251
parent 1c5b12f76301b86d0e5828c7d11ec7c36ffd0195
author James Smart <jsmart2021@gmail.com> 1492815904 -0700
committer Christoph Hellwig <hch@lst.de> 1493018749 +0200

Update ABORT processing for NVMET.

The driver with nvme had this routine stubbed.

Right now XRI_ABORTED_CQE is not handled and the FC NVMET
Transport has a new API for the driver.

Missing code path, new NVME abort API
Update ABORT processing for NVMET

There are 3 new FC NVMET Transport API/ template routines for NVMET:

lpfc_nvmet_xmt_fcp_release
This NVMET template callback routine called to release context
associated with an IO This routine is ALWAYS called last, even
if the IO was aborted or completed in error.

lpfc_nvmet_xmt_fcp_abort
This NVMET template callback routine called to abort an exchange that
has an IO in progress

nvmet_fc_rcv_fcp_req
When the lpfc driver receives an ABTS, this NVME FC transport layer
callback routine is called. For this case there are 2 paths thru the
driver: the driver either has an outstanding exchange / context for the
XRI to be aborted or not.  If not, a BA_RJT is issued otherwise a BA_ACC

NVMET Driver abort paths:

There are 2 paths for aborting an IO. The first one is we receive an IO and
decide not to process it because of lack of resources. An unsolicated ABTS
is immediately sent back to the initiator as a response.
lpfc_nvmet_unsol_fcp_buffer
            lpfc_nvmet_unsol_issue_abort  (XMIT_SEQUENCE_WQE)

The second one is we sent the IO up to the NVMET transport layer to
process, and for some reason the NVME Transport layer decided to abort the
IO before it completes all its phases. For this case there are 2 paths
thru the driver:
the driver either has an outstanding TSEND/TRECEIVE/TRSP WQE or no
outstanding WQEs are present for the exchange / context.
lpfc_nvmet_xmt_fcp_abort
    if (LPFC_NVMET_IO_INP)
        lpfc_nvmet_sol_fcp_issue_abort  (ABORT_WQE)
                lpfc_nvmet_sol_fcp_abort_cmp
    else
        lpfc_nvmet_unsol_fcp_issue_abort
                lpfc_nvmet_unsol_issue_abort  (XMIT_SEQUENCE_WQE)
                        lpfc_nvmet_unsol_fcp_abort_cmp

Context flags:
LPFC_NVMET_IOP - his flag signifies an IO is in progress on the exchange.
LPFC_NVMET_XBUSY  - this flag indicates the IO completed but the firmware
is still busy with the corresponding exchange. The exchange should not be
reused until after a XRI_ABORTED_CQE is received for that exchange.
LPFC_NVMET_ABORT_OP - this flag signifies an ABORT_WQE was issued on the
exchange.
LPFC_NVMET_CTX_RLS  - this flag signifies a context free was requested,
but we are deferring it due to an XBUSY or ABORT in progress.

A ctxlock is added to the context structure that is used whenever these
flags are set/read  within the context of an IO.
The LPFC_NVMET_CTX_RLS flag is only set in the defer_relase routine when
the transport has resolved all IO associated with the buffer. The flag is
cleared when the CTX is associated with a new IO.

An exchange can has both an LPFC_NVMET_XBUSY and a LPFC_NVMET_ABORT_OP
condition active simultaneously. Both conditions must complete before the
exchange is freed.
When the abort callback (lpfc_nvmet_xmt_fcp_abort) is envoked:
If there is an outstanding IO, the driver will issue an ABORT_WQE. This
should result in 3 completions for the exchange:
1) IO cmpl with XB bit set
2) Abort WQE cmpl
3) XRI_ABORTED_CQE cmpl
For this scenerio, after completion #1, the NVMET Transport IO rsp
callback is called.  After completion #2, no action is taken with respect
to the exchange / context.  After completion #3, the exchange context is
free for re-use on another IO.

If there is no outstanding activity on the exchange, the driver will send a
ABTS to the Initiator. Upon completion of this WQE, the exchange / context
is freed for re-use on another IO.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>