AHCI: Make distinct names for ports in /proc/interrupts

Currently all interrupts assigned to AHCI ports show up in
'/proc/interrupts' as 'ahci'. This fix adds port numbers as
suffixes and hence makes the descriptions distinct.
Reported-by: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/ata/ahci.c

@@ -1142,9 +1142,11 @@ int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis)
 		return rc;
 
 	for (i = 0; i < host->n_ports; i++) {
+		struct ahci_port_priv *pp = host->ports[i]->private_data;
+
 		rc = devm_request_threaded_irq(host->dev,
 			irq + i, ahci_hw_interrupt, ahci_thread_fn, IRQF_SHARED,
-			dev_driver_string(host->dev), host->ports[i]);
+			pp->irq_desc, host->ports[i]);
 		if (rc)
 			goto out_free_irqs;
 	}

drivers/ata/ahci.h

@@ -306,6 +306,7 @@ struct ahci_port_priv {
 	int			fbs_last_dev;	/* save FBS.DEV of last FIS */
 	/* enclosure management info per PM slot */
 	struct ahci_em_priv	em_priv[EM_MAX_SLOTS];
+	char			*irq_desc;	/* desc in /proc/interrupts */
 };
 
 struct ahci_host_priv {

drivers/ata/libahci.c

@@ -2234,6 +2234,16 @@ static int ahci_port_start(struct ata_port *ap)
 	if (!pp)
 		return -ENOMEM;
 
+	if (ap->host->n_ports > 1) {
+		pp->irq_desc = devm_kzalloc(dev, 8, GFP_KERNEL);
+		if (!pp->irq_desc) {
+			devm_kfree(dev, pp);
+			return -ENOMEM;
+		}
+		snprintf(pp->irq_desc, 8,
+			 "%s%d", dev_driver_string(dev), ap->port_no);
+	}
+
 	/* check FBS capability */
 	if ((hpriv->cap & HOST_CAP_FBS) && sata_pmp_supported(ap)) {
 		void __iomem *port_mmio = ahci_port_base(ap);