[PATCH 4/4] fnic: make interrupt mode configurable

[Hannes Reinecke <hare@kernel.org>]

In some environments (eg kdump) not all CPUs are online, so the MQ
mapping might be resulting in an invalid layout. So make the interrupt
mode settable via an 'fnic_intr_mode' module parameter and switch
to INTx if the 'reset_devices' kernel parameter is specified.

Signed-off-by: Hannes Reinecke <hare@kernel.org>
---
 drivers/scsi/fnic/fnic.h      |  2 +-
 drivers/scsi/fnic/fnic_isr.c  | 13 +++++++++----
 drivers/scsi/fnic/fnic_main.c | 10 +++++++++-
 3 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/fnic/fnic.h b/drivers/scsi/fnic/fnic.h
index 1199d701c3f5..c679283955e9 100644
--- a/drivers/scsi/fnic/fnic.h
+++ b/drivers/scsi/fnic/fnic.h
@@ -484,7 +484,7 @@ extern struct workqueue_struct *fnic_fip_queue;
 extern const struct attribute_group *fnic_host_groups[];
 
 void fnic_clear_intr_mode(struct fnic *fnic);
-int fnic_set_intr_mode(struct fnic *fnic);
+int fnic_set_intr_mode(struct fnic *fnic, unsigned int mode);
 int fnic_set_intr_mode_msix(struct fnic *fnic);
 void fnic_free_intr(struct fnic *fnic);
 int fnic_request_intr(struct fnic *fnic);
diff --git a/drivers/scsi/fnic/fnic_isr.c b/drivers/scsi/fnic/fnic_isr.c
index e16b76d537e8..b6594ad064ca 100644
--- a/drivers/scsi/fnic/fnic_isr.c
+++ b/drivers/scsi/fnic/fnic_isr.c
@@ -319,20 +319,25 @@ int fnic_set_intr_mode_msix(struct fnic *fnic)
 	return 1;
 }
 
-int fnic_set_intr_mode(struct fnic *fnic)
+int fnic_set_intr_mode(struct fnic *fnic, unsigned int intr_mode)
 {
 	int ret_status = 0;
 
 	/*
 	 * Set interrupt mode (INTx, MSI, MSI-X) depending
 	 * system capabilities.
-	 *
+	 */
+	if (intr_mode != VNIC_DEV_INTR_MODE_MSIX)
+		goto try_msi;
+	/*
 	 * Try MSI-X first
 	 */
 	ret_status = fnic_set_intr_mode_msix(fnic);
 	if (ret_status == 0)
 		return ret_status;
-
+try_msi:
+	if (intr_mode != VNIC_DEV_INTR_MODE_MSI)
+		goto try_intx;
 	/*
 	 * Next try MSI
 	 * We need 1 RQ, 1 WQ, 1 WQ_COPY, 3 CQs, and 1 INTR
@@ -358,7 +363,7 @@ int fnic_set_intr_mode(struct fnic *fnic)
 
 		return 0;
 	}
-
+try_intx:
 	/*
 	 * Next try INTx
 	 * We need 1 RQ, 1 WQ, 1 WQ_COPY, 3 CQs, and 3 INTRs
diff --git a/drivers/scsi/fnic/fnic_main.c b/drivers/scsi/fnic/fnic_main.c
index 870b265be41a..4bdd55958f59 100644
--- a/drivers/scsi/fnic/fnic_main.c
+++ b/drivers/scsi/fnic/fnic_main.c
@@ -97,6 +97,10 @@ module_param(pc_rscn_handling_feature_flag, uint, 0644);
 MODULE_PARM_DESC(pc_rscn_handling_feature_flag,
 		 "PCRSCN handling (0 for none. 1 to handle PCRSCN (default))");
 
+static unsigned int fnic_intr_mode = VNIC_DEV_INTR_MODE_MSIX;
+module_param(fnic_intr_mode, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(fnic_intr_mode, "Interrupt mode, 1 = INTx, 2 = MSI, 3 = MSIx (default: 3)");
+
 struct workqueue_struct *reset_fnic_work_queue;
 struct workqueue_struct *fnic_fip_queue;
 
@@ -869,7 +873,11 @@ static int fnic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	fnic_get_res_counts(fnic);
 
-	err = fnic_set_intr_mode(fnic);
+	/* Override interrupt selection during kdump */
+	if (reset_devices)
+		fnic_intr_mode = VNIC_DEV_INTR_MODE_INTX;
+
+	err = fnic_set_intr_mode(fnic, fnic_intr_mode);
 	if (err) {
 		dev_err(&fnic->pdev->dev, "Failed to set intr mode, "
 			     "aborting.\n");
-- 
2.43.0