struct kref ref;
};
+struct nvmet_fc_defer_fcp_req {
+ struct list_head req_list;
+ struct nvmefc_tgt_fcp_req *fcp_req;
+};
+
struct nvmet_fc_tgt_queue {
bool ninetypercent;
u16 qid;
struct nvmet_fc_tgt_assoc *assoc;
struct nvmet_fc_fcp_iod *fod; /* array of fcp_iods */
struct list_head fod_list;
+ struct list_head pending_cmd_list;
+ struct list_head avail_defer_list;
struct workqueue_struct *work_q;
struct kref ref;
} __aligned(sizeof(unsigned long long));
static int nvmet_fc_tgt_q_get(struct nvmet_fc_tgt_queue *queue);
static void nvmet_fc_tgtport_put(struct nvmet_fc_tgtport *tgtport);
static int nvmet_fc_tgtport_get(struct nvmet_fc_tgtport *tgtport);
+static void nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
+ struct nvmet_fc_fcp_iod *fod);
/* *********************** FC-NVME DMA Handling **************************** */
nvmet_fc_alloc_fcp_iod(struct nvmet_fc_tgt_queue *queue)
{
static struct nvmet_fc_fcp_iod *fod;
- unsigned long flags;
- spin_lock_irqsave(&queue->qlock, flags);
+ lockdep_assert_held(&queue->qlock);
+
fod = list_first_entry_or_null(&queue->fod_list,
struct nvmet_fc_fcp_iod, fcp_list);
if (fod) {
* will "inherit" that reference.
*/
}
- spin_unlock_irqrestore(&queue->qlock, flags);
return fod;
}
+static void
+nvmet_fc_queue_fcp_req(struct nvmet_fc_tgtport *tgtport,
+ struct nvmet_fc_tgt_queue *queue,
+ struct nvmefc_tgt_fcp_req *fcpreq)
+{
+ struct nvmet_fc_fcp_iod *fod = fcpreq->nvmet_fc_private;
+
+ /*
+ * put all admin cmds on hw queue id 0. All io commands go to
+ * the respective hw queue based on a modulo basis
+ */
+ fcpreq->hwqid = queue->qid ?
+ ((queue->qid - 1) % tgtport->ops->max_hw_queues) : 0;
+
+ if (tgtport->ops->target_features & NVMET_FCTGTFEAT_CMD_IN_ISR)
+ queue_work_on(queue->cpu, queue->work_q, &fod->work);
+ else
+ nvmet_fc_handle_fcp_rqst(tgtport, fod);
+}
+
static void
nvmet_fc_free_fcp_iod(struct nvmet_fc_tgt_queue *queue,
struct nvmet_fc_fcp_iod *fod)
{
struct nvmefc_tgt_fcp_req *fcpreq = fod->fcpreq;
struct nvmet_fc_tgtport *tgtport = fod->tgtport;
+ struct nvmet_fc_defer_fcp_req *deferfcp;
unsigned long flags;
fc_dma_sync_single_for_cpu(tgtport->dev, fod->rspdma,
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;
+
+ tgtport->ops->fcp_req_release(&tgtport->fc_target_port, fcpreq);
+
+ spin_lock_irqsave(&queue->qlock, flags);
+ deferfcp = list_first_entry_or_null(&queue->pending_cmd_list,
+ struct nvmet_fc_defer_fcp_req, req_list);
+ if (!deferfcp) {
+ list_add_tail(&fod->fcp_list, &fod->queue->fod_list);
+ spin_unlock_irqrestore(&queue->qlock, flags);
+
+ /* Release reference taken at queue lookup and fod allocation */
+ nvmet_fc_tgt_q_put(queue);
+ return;
+ }
+
+ /* Re-use the fod for the next pending cmd that was deferred */
+ list_del(&deferfcp->req_list);
+
+ fcpreq = deferfcp->fcp_req;
+
+ /* deferfcp can be reused for another IO at a later date */
+ list_add_tail(&deferfcp->req_list, &queue->avail_defer_list);
+
spin_unlock_irqrestore(&queue->qlock, flags);
+ /* Save NVME CMD IO in fod */
+ memcpy(&fod->cmdiubuf, fcpreq->rspaddr, fcpreq->rsplen);
+
+ /* Setup new fcpreq to be processed */
+ fcpreq->rspaddr = NULL;
+ fcpreq->rsplen = 0;
+ fcpreq->nvmet_fc_private = fod;
+ fod->fcpreq = fcpreq;
+ fod->active = true;
+
+ /* inform LLDD IO is now being processed */
+ tgtport->ops->defer_rcv(&tgtport->fc_target_port, fcpreq);
+
+ /* Submit deferred IO for processing */
+ nvmet_fc_queue_fcp_req(tgtport, queue, fcpreq);
+
/*
- * release the reference taken at queue lookup and fod allocation
+ * Leave the queue lookup get reference taken when
+ * fod was originally allocated.
*/
- nvmet_fc_tgt_q_put(queue);
-
- tgtport->ops->fcp_req_release(&tgtport->fc_target_port, fcpreq);
}
static int
queue->port = assoc->tgtport->port;
queue->cpu = nvmet_fc_queue_to_cpu(assoc->tgtport, qid);
INIT_LIST_HEAD(&queue->fod_list);
+ INIT_LIST_HEAD(&queue->avail_defer_list);
+ INIT_LIST_HEAD(&queue->pending_cmd_list);
atomic_set(&queue->connected, 0);
atomic_set(&queue->sqtail, 0);
atomic_set(&queue->rsn, 1);
{
struct nvmet_fc_tgtport *tgtport = queue->assoc->tgtport;
struct nvmet_fc_fcp_iod *fod = queue->fod;
+ struct nvmet_fc_defer_fcp_req *deferfcp;
unsigned long flags;
int i, writedataactive;
bool disconnect;
}
}
}
+
+ /* Cleanup defer'ed IOs in queue */
+ list_for_each_entry(deferfcp, &queue->avail_defer_list, req_list) {
+ list_del(&deferfcp->req_list);
+ kfree(deferfcp);
+ }
+
+ for (;;) {
+ deferfcp = list_first_entry_or_null(&queue->pending_cmd_list,
+ struct nvmet_fc_defer_fcp_req, req_list);
+ if (!deferfcp)
+ break;
+
+ list_del(&deferfcp->req_list);
+ spin_unlock_irqrestore(&queue->qlock, flags);
+
+ tgtport->ops->defer_rcv(&tgtport->fc_target_port,
+ deferfcp->fcp_req);
+
+ tgtport->ops->fcp_abort(&tgtport->fc_target_port,
+ deferfcp->fcp_req);
+
+ tgtport->ops->fcp_req_release(&tgtport->fc_target_port,
+ deferfcp->fcp_req);
+
+ kfree(deferfcp);
+
+ spin_lock_irqsave(&queue->qlock, flags);
+ }
spin_unlock_irqrestore(&queue->qlock, flags);
flush_workqueue(queue->work_q);
* Pass a FC-NVME FCP CMD IU received from the FC link to the nvmet-fc
* layer for processing.
*
- * The nvmet-fc layer will copy cmd payload to an internal structure for
- * processing. As such, upon completion of the routine, the LLDD may
- * immediately free/reuse the CMD IU buffer passed in the call.
+ * The nvmet_fc layer allocates a local job structure (struct
+ * nvmet_fc_fcp_iod) from the queue for the io and copies the
+ * CMD IU buffer to the job structure. As such, on a successful
+ * completion (returns 0), the LLDD may immediately free/reuse
+ * the CMD IU buffer passed in the call.
+ *
+ * However, in some circumstances, due to the packetized nature of FC
+ * and the api of the FC LLDD which may issue a hw command to send the
+ * response, but the LLDD may not get the hw completion for that command
+ * and upcall the nvmet_fc layer before a new command may be
+ * asynchronously received - its possible for a command to be received
+ * before the LLDD and nvmet_fc have recycled the job structure. It gives
+ * the appearance of more commands received than fits in the sq.
+ * To alleviate this scenario, a temporary queue is maintained in the
+ * transport for pending LLDD requests waiting for a queue job structure.
+ * In these "overrun" cases, a temporary queue element is allocated
+ * the LLDD request and CMD iu buffer information remembered, and the
+ * routine returns a -EOVERFLOW status. Subsequently, when a queue job
+ * structure is freed, it is immediately reallocated for anything on the
+ * pending request list. The LLDDs defer_rcv() callback is called,
+ * informing the LLDD that it may reuse the CMD IU buffer, and the io
+ * is then started normally with the transport.
*
- * If this routine returns error, the lldd should abort the exchange.
+ * The LLDD, when receiving an -EOVERFLOW completion status, is to treat
+ * the completion as successful but must not reuse the CMD IU buffer
+ * until the LLDD's defer_rcv() callback has been called for the
+ * corresponding struct nvmefc_tgt_fcp_req pointer.
+ *
+ * If there is any other condition in which an error occurs, the
+ * transport will return a non-zero status indicating the error.
+ * In all cases other than -EOVERFLOW, the transport has not accepted the
+ * request and the LLDD should abort the exchange.
*
* @target_port: pointer to the (registered) target port the FCP CMD IU
* was received on.
struct nvme_fc_cmd_iu *cmdiu = cmdiubuf;
struct nvmet_fc_tgt_queue *queue;
struct nvmet_fc_fcp_iod *fod;
+ struct nvmet_fc_defer_fcp_req *deferfcp;
+ unsigned long flags;
/* validate iu, so the connection id can be used to find the queue */
if ((cmdiubuf_len != sizeof(*cmdiu)) ||
* when the fod is freed.
*/
+ spin_lock_irqsave(&queue->qlock, flags);
+
fod = nvmet_fc_alloc_fcp_iod(queue);
- if (!fod) {
+ if (fod) {
+ spin_unlock_irqrestore(&queue->qlock, flags);
+
+ fcpreq->nvmet_fc_private = fod;
+ fod->fcpreq = fcpreq;
+
+ memcpy(&fod->cmdiubuf, cmdiubuf, cmdiubuf_len);
+
+ nvmet_fc_queue_fcp_req(tgtport, queue, fcpreq);
+
+ return 0;
+ }
+
+ if (!tgtport->ops->defer_rcv) {
+ spin_unlock_irqrestore(&queue->qlock, flags);
/* release the queue lookup reference */
nvmet_fc_tgt_q_put(queue);
return -ENOENT;
}
- fcpreq->nvmet_fc_private = fod;
- fod->fcpreq = fcpreq;
- /*
- * put all admin cmds on hw queue id 0. All io commands go to
- * the respective hw queue based on a modulo basis
- */
- fcpreq->hwqid = queue->qid ?
- ((queue->qid - 1) % tgtport->ops->max_hw_queues) : 0;
- memcpy(&fod->cmdiubuf, cmdiubuf, cmdiubuf_len);
+ deferfcp = list_first_entry_or_null(&queue->avail_defer_list,
+ struct nvmet_fc_defer_fcp_req, req_list);
+ if (deferfcp) {
+ /* Just re-use one that was previously allocated */
+ list_del(&deferfcp->req_list);
+ } else {
+ spin_unlock_irqrestore(&queue->qlock, flags);
- if (tgtport->ops->target_features & NVMET_FCTGTFEAT_CMD_IN_ISR)
- queue_work_on(queue->cpu, queue->work_q, &fod->work);
- else
- nvmet_fc_handle_fcp_rqst(tgtport, fod);
+ /* Now we need to dynamically allocate one */
+ deferfcp = kmalloc(sizeof(*deferfcp), GFP_KERNEL);
+ if (!deferfcp) {
+ /* release the queue lookup reference */
+ nvmet_fc_tgt_q_put(queue);
+ return -ENOMEM;
+ }
+ spin_lock_irqsave(&queue->qlock, flags);
+ }
- return 0;
+ /* For now, use rspaddr / rsplen to save payload information */
+ fcpreq->rspaddr = cmdiubuf;
+ fcpreq->rsplen = cmdiubuf_len;
+ deferfcp->fcp_req = fcpreq;
+
+ /* defer processing till a fod becomes available */
+ list_add_tail(&deferfcp->req_list, &queue->pending_cmd_list);
+
+ /* NOTE: the queue lookup reference is still valid */
+
+ spin_unlock_irqrestore(&queue->qlock, flags);
+
+ return -EOVERFLOW;
}
EXPORT_SYMBOL_GPL(nvmet_fc_rcv_fcp_req);
projects / kernel.git / commitdiff