From: Dave Marquardt <[email protected]> Add ibmvfc_interrupt_async_subq(), an IRQ handler dedicated to asynchronous sub-CRQ events from the adapter. The handler disables the sub-CRQ IRQ and then calls ibmvfc_drain_async_subq() to consume all pending entries before re-enabling interrupts.
Add ibmvfc_next_async_scrq() to traverse the async sub-CRQ ring directly via msgs.async_scrq[], returning a typed struct ibmvfc_async_sub_crq * without the cast that would be needed when going through ibmvfc_next_scrq(). ibmvfc_drain_async_subq() separates ring drain from event dispatch. With host_lock and q_lock both held, it loops over available entries via ibmvfc_next_async_scrq() and passes each one to ibmvfc_queue_async_subq_entry(). That helper allocates a struct ibmvfc_async_drain_entry node with kzalloc_obj(..., GFP_ATOMIC), copies the event into it, and appends it to a local doneq list. The node is zero-allocated because struct ibmvfc_async_crq_event is a union and the copied sub-CRQ is smaller than the main CRQ member; the remaining bytes are later copied wholesale into the FPIN work item. The valid bit is cleared and a write barrier issued regardless of whether the allocation succeeded. If the GFP_ATOMIC allocation fails, a ratelimited error is logged and that event is dropped; it is not retried. After draining the inner loop, both locks are still held while the sub-CRQ IRQ is re-enabled and one final ring check is performed to close the race between the last drain and IRQ re-enable; any newly arrived entry is collected the same way. Only after both locks are released does ibmvfc_drain_async_subq() walk doneq, re-taking host_lock around each ibmvfc_handle_async() call before freeing the node. Signed-off-by: Dave Marquardt <[email protected]> Signed-off-by: Tyrel Datwyler <[email protected]> --- drivers/scsi/ibmvscsi/ibmvfc-core.c | 100 ++++++++++++++++++++++++++++++++++++ 1 file changed, 100 insertions(+) diff --git a/drivers/scsi/ibmvscsi/ibmvfc-core.c b/drivers/scsi/ibmvscsi/ibmvfc-core.c index 7406e7182777..5dba084086d5 100644 --- a/drivers/scsi/ibmvscsi/ibmvfc-core.c +++ b/drivers/scsi/ibmvscsi/ibmvfc-core.c @@ -4456,6 +4456,106 @@ static struct ibmvfc_crq *ibmvfc_next_scrq(struct ibmvfc_queue *scrq) return crq; } +static struct ibmvfc_async_sub_crq *ibmvfc_next_async_scrq(struct ibmvfc_queue *scrq) +{ + struct ibmvfc_async_sub_crq *crq; + + crq = &scrq->msgs.async_scrq[scrq->cur]; + if (crq->valid & 0x80) { + if (++scrq->cur == scrq->size) + scrq->cur = 0; + rmb(); + } else + crq = NULL; + + return crq; +} + +struct ibmvfc_async_drain_entry { + struct ibmvfc_async_crq_event event; + struct list_head list; +}; + +/** + * ibmvfc_queue_async_subq_entry - Copy an async sub-CRQ entry to a deferred list + * @vhost: ibmvfc host struct + * @crq: async sub-CRQ entry to consume + * @doneq: list on which to queue the copied event for later dispatch + * + * Copies @crq into a newly allocated ibmvfc_async_drain_entry and appends it + * to @doneq. If the allocation fails, a ratelimited error is logged and the + * event is dropped. In either case the entry is returned to the adapter by + * clearing its valid bit. + **/ +static void ibmvfc_queue_async_subq_entry(struct ibmvfc_host *vhost, + struct ibmvfc_async_sub_crq *crq, + struct list_head *doneq) +{ + struct ibmvfc_async_drain_entry *entry; + + entry = kzalloc_obj(*entry, GFP_ATOMIC); + if (entry) { + entry->event.type = IBMVFC_ASYNC_CRQ_SUB; + entry->event.subq = *crq; + list_add_tail(&entry->list, doneq); + } else + dev_err_ratelimited(vhost->dev, + "Couldn't allocate async drain entry\n"); + crq->valid = 0; + wmb(); /* complete write */ +} + +static void ibmvfc_drain_async_subq(struct ibmvfc_queue *scrq) +{ + struct ibmvfc_host *vhost = scrq->vhost; + struct ibmvfc_async_drain_entry *entry, *temp; + struct ibmvfc_async_sub_crq *crq; + LIST_HEAD(doneq); + unsigned long flags; + int done = 0; + + spin_lock_irqsave(&vhost->host->host_lock, flags); + spin_lock(scrq->q_lock); + while (!done) { + while ((crq = ibmvfc_next_async_scrq(scrq)) != NULL) + ibmvfc_queue_async_subq_entry(vhost, crq, &doneq); + + ibmvfc_toggle_scrq_irq(scrq, 1); + crq = ibmvfc_next_async_scrq(scrq); + if (crq != NULL) { + ibmvfc_toggle_scrq_irq(scrq, 0); + ibmvfc_queue_async_subq_entry(vhost, crq, &doneq); + } else + done = 1; + } + spin_unlock(scrq->q_lock); + spin_unlock_irqrestore(&vhost->host->host_lock, flags); + + list_for_each_entry_safe(entry, temp, &doneq, list) { + list_del(&entry->list); + spin_lock_irqsave(&vhost->host->host_lock, flags); + ibmvfc_handle_async(&entry->event, vhost); + spin_unlock_irqrestore(&vhost->host->host_lock, flags); + kfree(entry); + } +} + +/** + * ibmvfc_interrupt_async_subq - Handle an async event from the adapter + * @irq: interrupt request + * @scrq_instance: async subq + * + **/ +static irqreturn_t __maybe_unused ibmvfc_interrupt_async_subq(int irq, void *scrq_instance) +{ + struct ibmvfc_queue *scrq = (struct ibmvfc_queue *)scrq_instance; + + ibmvfc_toggle_scrq_irq(scrq, 0); + ibmvfc_drain_async_subq(scrq); + + return IRQ_HANDLED; +} + static void ibmvfc_drain_sub_crq(struct ibmvfc_queue *scrq) { struct ibmvfc_crq *crq; -- 2.56.0
