[PATCH v6 5/8] scsi: ibmvfc: add interrupt routine for asynchronous sub CRQ
From: Dave Marquardt via B4 Relay <devnull+davemarq.linux.ibm.com@kernel.org>
Date: 2026-08-17 20:28:01
Also in:
b4-sent, linux-scsi, lkml
Subsystem:
ibm power virtual fc device drivers, linux for powerpc (32-bit and 64-bit), scsi subsystem, the rest · Maintainers:
Tyrel Datwyler, Madhavan Srinivasan, "James E.J. Bottomley", "Martin K. Petersen", Linus Torvalds
From: Dave Marquardt <redacted> 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. ibmvfc_drain_async_subq() holds both the host lock and the per-queue q_lock while processing. It loops over available CRQ entries via ibmvfc_next_scrq(), dispatching each to ibmvfc_handle_async() with the async flag set, then clears the valid bit and issues a write barrier. After draining, it re-enables the sub-CRQ IRQ and performs one final check for a newly arrived entry to close the IRQ-enable race; if one is found it is processed before exiting the loop. --- drivers/scsi/ibmvscsi/ibmvfc-core.c | 46 +++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+)
diff --git a/drivers/scsi/ibmvscsi/ibmvfc-core.c b/drivers/scsi/ibmvscsi/ibmvfc-core.c
index 37ee8f00322a..23c1a4cb40d9 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc-core.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc-core.c@@ -4337,6 +4337,52 @@ static struct ibmvfc_crq *ibmvfc_next_scrq(struct ibmvfc_queue *scrq) return crq; } +static void ibmvfc_drain_async_subq(struct ibmvfc_queue *scrq) +{ + struct ibmvfc_host *vhost = scrq->vhost; + struct ibmvfc_crq *crq; + 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_scrq(scrq)) != NULL) { + ibmvfc_handle_async(crq, scrq->vhost, true); + crq->valid = 0; + wmb(); /* complete write */ + } + + ibmvfc_toggle_scrq_irq(scrq, 1); + crq = ibmvfc_next_scrq(scrq); + if (crq != NULL) { + ibmvfc_toggle_scrq_irq(scrq, 0); + ibmvfc_handle_async(crq, scrq->vhost, true); + crq->valid = 0; + wmb(); /* complete write */ + } else + done = 1; + } + spin_unlock(scrq->q_lock); + spin_unlock_irqrestore(vhost->host->host_lock, flags); +} + +/** + * ibmvfc_interrupt_async_subq - Handle an async event from the adapter + * @irq: interrupt request + * @scrq_instance: async subq + * + **/ +static irqreturn_t 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;
--
2.55.0