nvmet_fc: Rework target side abort handling

target transport:
----------------------
There are cases when there is a need to abort in-progress target
operations (writedata) so that controller termination or errors can
clean up. That can't happen currently as the abort is another target
op type, so it can't be used till the running one finishes (and it may
not).  Solve by removing the abort op type and creating a separate
downcall from the transport to the lldd to request an io to be aborted.

The transport will abort ios on queue teardown or io errors. In general
the transport tries to call the lldd abort only when the io state is
idle. Meaning: ops that transmit data (readdata or rsp) will always
finish their transmit (or the lldd will see a state on the
link or initiator port that fails the transmit) and the done call for
the operation will occur. The transport will wait for the op done
upcall before calling the abort function, and as the io is idle, the
io can be cleaned up immediately after the abort call; Similarly, ios
that are not waiting for data or transmitting data must be in the nvmet
layer being processed. The transport will wait for the nvmet layer
completion before calling the abort function, and as the io is idle,
the io can be cleaned up immediately after the abort call; As for ops
that are waiting for data (writedata), they may be outstanding
indefinitely if the lldd doesn't see a condition where the initiatior
port or link is bad. In those cases, the transport will call the abort
function and wait for the lldd's op done upcall for the operation, where
it will then clean up the io.

Additionally, if a lldd receives an ABTS and matches it to an outstanding
request in the transport, A new new transport upcall was created to abort
the outstanding request in the transport. The transport expects any
outstanding op call (readdata or writedata) will completed by the lldd and
the operation upcall made. The transport doesn't act on the reported
abort (e.g. clean up the io) until an op done upcall occurs, a new op is
attempted, or the nvmet layer completes the io processing.

fcloop:
----------------------
Updated to support the new target apis.
On fcp io aborts from the initiator, the loopback context is updated to
NULL out the half that has completed. The initiator side is immediately
called after the abort request with an io completion (abort status).
On fcp io aborts from the target, the io is stopped and the initiator side
sees it as an aborted io. Target side ops, perhaps in progress while the
initiator side is done, continue but noop the data movement as there's no
structure on the initiator side to reference.

patch also contains:
----------------------
Revised lpfc to support the new abort api

commonized rsp buffer syncing and nulling of private data based on
calling paths.

errors in op done calls don't take action on the fod. They're bad
operations which implies the fod may be bad.

Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

1 files changed, 151 insertions, 54 deletions

diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index d7068f039904..e5d30bbb1b10 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -82,6 +82,8 @@ struct nvmet_fc_fcp_iod {
 	enum nvmet_fcp_datadir		io_dir;
 	bool				active;
 	bool				abort;
+	bool				aborted;
+	bool				writedataactive;
 	spinlock_t			flock;
 
 	struct nvmet_req		req;
@@ -420,6 +422,9 @@ nvmet_fc_prep_fcp_iodlist(struct nvmet_fc_tgtport *tgtport,
 		fod->tgtport = tgtport;
 		fod->queue = queue;
 		fod->active = false;
+		fod->abort = false;
+		fod->aborted = false;
+		fod->fcpreq = NULL;
 		list_add_tail(&fod->fcp_list, &queue->fod_list);
 		spin_lock_init(&fod->flock);
 
@@ -466,7 +471,6 @@ nvmet_fc_alloc_fcp_iod(struct nvmet_fc_tgt_queue *queue)
 	if (fod) {
 		list_del(&fod->fcp_list);
 		fod->active = true;
-		fod->abort = false;
 		/*
 		 * no queue reference is taken, as it was taken by the
 		 * queue lookup just prior to the allocation. The iod
@@ -486,9 +490,18 @@ nvmet_fc_free_fcp_iod(struct nvmet_fc_tgt_queue *queue,
 	struct nvmet_fc_tgtport *tgtport = fod->tgtport;
 	unsigned long flags;
 
+	fc_dma_sync_single_for_cpu(tgtport->dev, fod->rspdma,
+				sizeof(fod->rspiubuf), DMA_TO_DEVICE);
+
+	fcpreq->nvmet_fc_private = NULL;
+
 	spin_lock_irqsave(&queue->qlock, flags);
 	list_add_tail(&fod->fcp_list, &fod->queue->fod_list);
 	fod->active = false;
+	fod->abort = false;
+	fod->aborted = false;
+	fod->writedataactive = false;
+	fod->fcpreq = NULL;
 	spin_unlock_irqrestore(&queue->qlock, flags);
 
 	/*
@@ -623,32 +636,12 @@ nvmet_fc_tgt_q_get(struct nvmet_fc_tgt_queue *queue)
 
 
 static void
-nvmet_fc_abort_op(struct nvmet_fc_tgtport *tgtport,
-				struct nvmefc_tgt_fcp_req *fcpreq)
-{
-	int ret;
-
-	fcpreq->op = NVMET_FCOP_ABORT;
-	fcpreq->offset = 0;
-	fcpreq->timeout = 0;
-	fcpreq->transfer_length = 0;
-	fcpreq->transferred_length = 0;
-	fcpreq->fcp_error = 0;
-	fcpreq->sg_cnt = 0;
-
-	ret = tgtport->ops->fcp_op(&tgtport->fc_target_port, fcpreq);
-	if (ret)
-		/* should never reach here !! */
-		WARN_ON(1);
-}
-
-
-static void
 nvmet_fc_delete_target_queue(struct nvmet_fc_tgt_queue *queue)
 {
+	struct nvmet_fc_tgtport *tgtport = queue->assoc->tgtport;
 	struct nvmet_fc_fcp_iod *fod = queue->fod;
 	unsigned long flags;
-	int i;
+	int i, writedataactive;
 	bool disconnect;
 
 	disconnect = atomic_xchg(&queue->connected, 0);
@@ -659,7 +652,20 @@ nvmet_fc_delete_target_queue(struct nvmet_fc_tgt_queue *queue)
 		if (fod->active) {
 			spin_lock(&fod->flock);
 			fod->abort = true;
+			writedataactive = fod->writedataactive;
 			spin_unlock(&fod->flock);
+			/*
+			 * only call lldd abort routine if waiting for
+			 * writedata. other outstanding ops should finish
+			 * on their own.
+			 */
+			if (writedataactive) {
+				spin_lock(&fod->flock);
+				fod->aborted = true;
+				spin_unlock(&fod->flock);
+				tgtport->ops->fcp_abort(
+					&tgtport->fc_target_port, fod->fcpreq);
+			}
 		}
 	}
 	spin_unlock_irqrestore(&queue->qlock, flags);
@@ -853,6 +859,7 @@ nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
 	int ret, idx;
 
 	if (!template->xmt_ls_rsp || !template->fcp_op ||
+	    !template->fcp_abort ||
 	    !template->fcp_req_release || !template->targetport_delete ||
 	    !template->max_hw_queues || !template->max_sgl_segments ||
 	    !template->max_dif_sgl_segments || !template->dma_boundary) {
@@ -1718,6 +1725,26 @@ nvmet_fc_prep_fcp_rsp(struct nvmet_fc_tgtport *tgtport,
 static void nvmet_fc_xmt_fcp_op_done(struct nvmefc_tgt_fcp_req *fcpreq);
 
 static void
+nvmet_fc_abort_op(struct nvmet_fc_tgtport *tgtport,
+				struct nvmet_fc_fcp_iod *fod)
+{
+	struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
+
+	/* data no longer needed */
+	nvmet_fc_free_tgt_pgs(fod);
+
+	/*
+	 * if an ABTS was received or we issued the fcp_abort early
+	 * don't call abort routine again.
+	 */
+	/* no need to take lock - lock was taken earlier to get here */
+	if (!fod->aborted)
+		tgtport->ops->fcp_abort(&tgtport->fc_target_port, fcpreq);
+
+	nvmet_fc_free_fcp_iod(fod->queue, fod);
+}
+
+static void
 nvmet_fc_xmt_fcp_rsp(struct nvmet_fc_tgtport *tgtport,
 				struct nvmet_fc_fcp_iod *fod)
 {
@@ -1730,7 +1757,7 @@ nvmet_fc_xmt_fcp_rsp(struct nvmet_fc_tgtport *tgtport,
 
 	ret = tgtport->ops->fcp_op(&tgtport->fc_target_port, fod->fcpreq);
 	if (ret)
-		nvmet_fc_abort_op(tgtport, fod->fcpreq);
+		nvmet_fc_abort_op(tgtport, fod);
 }
 
 static void
@@ -1739,6 +1766,7 @@ nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport,
 {
 	struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
 	struct scatterlist *sg, *datasg;
+	unsigned long flags;
 	u32 tlen, sg_off;
 	int ret;
 
@@ -1803,10 +1831,13 @@ nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport,
 		 */
 		fod->abort = true;
 
-		if (op == NVMET_FCOP_WRITEDATA)
+		if (op == NVMET_FCOP_WRITEDATA) {
+			spin_lock_irqsave(&fod->flock, flags);
+			fod->writedataactive = false;
+			spin_unlock_irqrestore(&fod->flock, flags);
 			nvmet_req_complete(&fod->req,
 					NVME_SC_FC_TRANSPORT_ERROR);
-		else /* NVMET_FCOP_READDATA or NVMET_FCOP_READDATA_RSP */ {
+		} else /* NVMET_FCOP_READDATA or NVMET_FCOP_READDATA_RSP */ {
 			fcpreq->fcp_error = ret;
 			fcpreq->transferred_length = 0;
 			nvmet_fc_xmt_fcp_op_done(fod->fcpreq);
@@ -1814,6 +1845,27 @@ nvmet_fc_transfer_fcp_data(struct nvmet_fc_tgtport *tgtport,
 	}
 }
 
+static inline bool
+__nvmet_fc_fod_op_abort(struct nvmet_fc_fcp_iod *fod, bool abort)
+{
+	struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
+	struct nvmet_fc_tgtport *tgtport = fod->tgtport;
+
+	/* if in the middle of an io and we need to tear down */
+	if (abort) {
+		if (fcpreq->op == NVMET_FCOP_WRITEDATA) {
+			nvmet_req_complete(&fod->req,
+					NVME_SC_FC_TRANSPORT_ERROR);
+			return true;
+		}
+
+		nvmet_fc_abort_op(tgtport, fod);
+		return true;
+	}
+
+	return false;
+}
+
 /*
  * actual done handler for FCP operations when completed by the lldd
  */
@@ -1827,22 +1879,20 @@ nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
 
 	spin_lock_irqsave(&fod->flock, flags);
 	abort = fod->abort;
+	fod->writedataactive = false;
 	spin_unlock_irqrestore(&fod->flock, flags);
 
-	/* if in the middle of an io and we need to tear down */
-	if (abort && fcpreq->op != NVMET_FCOP_ABORT) {
-		/* data no longer needed */
-		nvmet_fc_free_tgt_pgs(fod);
-
-		nvmet_req_complete(&fod->req, fcpreq->fcp_error);
-		return;
-	}
-
 	switch (fcpreq->op) {
 
 	case NVMET_FCOP_WRITEDATA:
+		if (__nvmet_fc_fod_op_abort(fod, abort))
+			return;
 		if (fcpreq->fcp_error ||
 		    fcpreq->transferred_length != fcpreq->transfer_length) {
+			spin_lock(&fod->flock);
+			fod->abort = true;
+			spin_unlock(&fod->flock);
+
 			nvmet_req_complete(&fod->req,
 					NVME_SC_FC_TRANSPORT_ERROR);
 			return;
@@ -1850,6 +1900,10 @@ nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
 
 		fod->offset += fcpreq->transferred_length;
 		if (fod->offset != fod->total_length) {
+			spin_lock_irqsave(&fod->flock, flags);
+			fod->writedataactive = true;
+			spin_unlock_irqrestore(&fod->flock, flags);
+
 			/* transfer the next chunk */
 			nvmet_fc_transfer_fcp_data(tgtport, fod,
 						NVMET_FCOP_WRITEDATA);
@@ -1864,12 +1918,11 @@ nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
 
 	case NVMET_FCOP_READDATA:
 	case NVMET_FCOP_READDATA_RSP:
+		if (__nvmet_fc_fod_op_abort(fod, abort))
+			return;
 		if (fcpreq->fcp_error ||
 		    fcpreq->transferred_length != fcpreq->transfer_length) {
-			/* data no longer needed */
-			nvmet_fc_free_tgt_pgs(fod);
-
-			nvmet_fc_abort_op(tgtport, fod->fcpreq);
+			nvmet_fc_abort_op(tgtport, fod);
 			return;
 		}
 
@@ -1878,8 +1931,6 @@ nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
 		if (fcpreq->op == NVMET_FCOP_READDATA_RSP) {
 			/* data no longer needed */
 			nvmet_fc_free_tgt_pgs(fod);
-			fc_dma_sync_single_for_cpu(tgtport->dev, fod->rspdma,
-					sizeof(fod->rspiubuf), DMA_TO_DEVICE);
 			nvmet_fc_free_fcp_iod(fod->queue, fod);
 			return;
 		}
@@ -1902,15 +1953,12 @@ nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
 		break;
 
 	case NVMET_FCOP_RSP:
-	case NVMET_FCOP_ABORT:
-		fc_dma_sync_single_for_cpu(tgtport->dev, fod->rspdma,
-				sizeof(fod->rspiubuf), DMA_TO_DEVICE);
+		if (__nvmet_fc_fod_op_abort(fod, abort))
+			return;
 		nvmet_fc_free_fcp_iod(fod->queue, fod);
 		break;
 
 	default:
-		nvmet_fc_free_tgt_pgs(fod);
-		nvmet_fc_abort_op(tgtport, fod->fcpreq);
 		break;
 	}
 }
@@ -1958,10 +2006,7 @@ __nvmet_fc_fcp_nvme_cmd_done(struct nvmet_fc_tgtport *tgtport,
 		fod->queue->sqhd = cqe->sq_head;
 
 	if (abort) {
-		/* data no longer needed */
-		nvmet_fc_free_tgt_pgs(fod);
-
-		nvmet_fc_abort_op(tgtport, fod->fcpreq);
+		nvmet_fc_abort_op(tgtport, fod);
 		return;
 	}
 
@@ -2057,8 +2102,8 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 				&fod->queue->nvme_cq,
 				&fod->queue->nvme_sq,
 				&nvmet_fc_tgt_fcp_ops);
-	if (!ret) {	/* bad SQE content */
-		nvmet_fc_abort_op(tgtport, fod->fcpreq);
+	if (!ret) {	/* bad SQE content or invalid ctrl state */
+		nvmet_fc_abort_op(tgtport, fod);
 		return;
 	}
 
@@ -2098,7 +2143,7 @@ nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
 	return;
 
 transport_error:
-	nvmet_fc_abort_op(tgtport, fod->fcpreq);
+	nvmet_fc_abort_op(tgtport, fod);
 }
 
 /*
@@ -2151,7 +2196,6 @@ nvmet_fc_rcv_fcp_req(struct nvmet_fc_target_port *target_port,
 			(be16_to_cpu(cmdiu->iu_len) != (sizeof(*cmdiu)/4)))
 		return -EIO;
 
-
 	queue = nvmet_fc_find_target_queue(tgtport,
 				be64_to_cpu(cmdiu->connection_id));
 	if (!queue)
@@ -2190,6 +2234,59 @@ nvmet_fc_rcv_fcp_req(struct nvmet_fc_target_port *target_port,
 }
 EXPORT_SYMBOL_GPL(nvmet_fc_rcv_fcp_req);
 
+/**
+ * nvmet_fc_rcv_fcp_abort - transport entry point called by an LLDD
+ *                       upon the reception of an ABTS for a FCP command
+ *
+ * Notify the transport that an ABTS has been received for a FCP command
+ * that had been given to the transport via nvmet_fc_rcv_fcp_req(). The
+ * LLDD believes the command is still being worked on
+ * (template_ops->fcp_req_release() has not been called).
+ *
+ * The transport will wait for any outstanding work (an op to the LLDD,
+ * which the lldd should complete with error due to the ABTS; or the
+ * completion from the nvmet layer of the nvme command), then will
+ * stop processing and call the nvmet_fc_rcv_fcp_req() callback to
+ * return the i/o context to the LLDD.  The LLDD may send the BA_ACC
+ * to the ABTS either after return from this function (assuming any
+ * outstanding op work has been terminated) or upon the callback being
+ * called.
+ *
+ * @target_port: pointer to the (registered) target port the FCP CMD IU
+ *              was received on.
+ * @fcpreq:     pointer to the fcpreq request structure that corresponds
+ *              to the exchange that received the ABTS.
+ */
+void
+nvmet_fc_rcv_fcp_abort(struct nvmet_fc_target_port *target_port,
+			struct nvmefc_tgt_fcp_req *fcpreq)
+{
+	struct nvmet_fc_fcp_iod *fod = fcpreq->nvmet_fc_private;
+	struct nvmet_fc_tgt_queue *queue;
+	unsigned long flags;
+
+	if (!fod || fod->fcpreq != fcpreq)
+		/* job appears to have already completed, ignore abort */
+		return;
+
+	queue = fod->queue;
+
+	spin_lock_irqsave(&queue->qlock, flags);
+	if (fod->active) {
+		/*
+		 * mark as abort. The abort handler, invoked upon completion
+		 * of any work, will detect the aborted status and do the
+		 * callback.
+		 */
+		spin_lock(&fod->flock);
+		fod->abort = true;
+		fod->aborted = true;
+		spin_unlock(&fod->flock);
+	}
+	spin_unlock_irqrestore(&queue->qlock, flags);
+}
+EXPORT_SYMBOL_GPL(nvmet_fc_rcv_fcp_abort);
+
 enum {
 	FCT_TRADDR_ERR		= 0,
 	FCT_TRADDR_WWNN		= 1 << 0,