net:mana: Introduce new gic context and refcount for interrupt context

To allow Ethernet EQs share or use MSIx and RDMA EQs on the same MSIx,
introduce gic context and allow driver to create an interrupt context
on an assigned/unassigned MSIx.

Author: longlimsft

drivers/net/ethernet/microsoft/mana/gdma_main.c

@@ -1384,6 +1384,129 @@ static irqreturn_t mana_gd_intr(int irq, void *arg)
 	return IRQ_HANDLED;
 }
 
+void gdma_put_gic(struct gdma_context *gc, bool use_bitmap, int msi)
+{
+	struct pci_dev *dev = to_pci_dev(gc->dev);
+	struct msi_map irq_map;
+	struct gdma_irq_context *gic;
+	int irq;
+
+	mutex_lock(&gc->gic_mutex);
+
+	gic = xa_load(&gc->irq_contexts, msi);
+	if (WARN_ON(!gic)) {
+		mutex_unlock(&gc->gic_mutex);
+		return;
+	}
+
+	if (!refcount_dec_and_test(&gic->refcount))
+		goto clear_bitmap;
+
+	irq = pci_irq_vector(dev, msi);
+
+	irq_update_affinity_hint(irq, NULL);
+	free_irq(irq, gic);
+
+	irq_map.virq = irq;
+	irq_map.index = msi;
+	pci_msix_free_irq(dev, irq_map);
+
+	xa_erase(&gc->irq_contexts, msi);
+	kfree(gic);
+
+clear_bitmap:
+	if (use_bitmap)
+		clear_bit(msi, gc->msi_bitmap);
+
+	mutex_unlock(&gc->gic_mutex);
+}
+EXPORT_SYMBOL_NS(gdma_put_gic, "NET_MANA");
+
+struct gdma_irq_context *gdma_get_gic(struct gdma_context *gc, bool use_bitmap,
+				      u16 port_index, int queue_index,
+				      int *msi_requested)
+{
+	struct gdma_irq_context *gic;
+	struct pci_dev *dev = to_pci_dev(gc->dev);
+	struct msi_map irq_map;
+	int irq;
+	int msi;
+	int err;
+
+	mutex_lock(&gc->gic_mutex);
+
+	if (use_bitmap) {
+		msi = find_first_zero_bit(gc->msi_bitmap, gc->num_msix_usable);
+		*msi_requested = msi;
+	} else {
+		msi = *msi_requested;
+	}
+
+	gic = xa_load(&gc->irq_contexts, msi);
+	if (gic) {
+		refcount_inc(&gic->refcount);
+		if (use_bitmap)
+			set_bit(msi, gc->msi_bitmap);
+		goto out;
+	}
+
+	irq = pci_irq_vector(dev, msi);
+	if (irq == -EINVAL) {
+		irq_map = pci_msix_alloc_irq_at(dev, msi, NULL);
+		if (!irq_map.virq) {
+			err = irq_map.index;
+			dev_err(gc->dev,
+				"Failed to alloc irq_map msi %d err %d\n",
+				msi, err);
+			gic = NULL;
+			goto out;
+		}
+		irq = irq_map.virq;
+		msi = irq_map.index;
+	}
+
+	gic = kzalloc(sizeof(*gic), GFP_KERNEL);
+	if (!gic) {
+		dev_err(gc->dev, "Failed to allocate gic\n");
+		goto out;
+	}
+	gic->handler = mana_gd_process_eq_events;
+	gic->msi = msi;
+	gic->irq = irq;
+	INIT_LIST_HEAD(&gic->eq_list);
+	spin_lock_init(&gic->lock);
+
+	if (!gic->msi)
+		snprintf(gic->name, MANA_IRQ_NAME_SZ, "mana_hwc@pci:%s",
+			 pci_name(dev));
+	else if (use_bitmap)
+		snprintf(gic->name, MANA_IRQ_NAME_SZ, "mana_p%dq%d@pci:%s",
+			 port_index, queue_index, pci_name(dev));
+	else
+		snprintf(gic->name, MANA_IRQ_NAME_SZ, "mana_q%d@pci:%s",
+			 queue_index, pci_name(dev));
+
+	err = request_irq(irq, mana_gd_intr, 0, gic->name, gic);
+	if (err) {
+		dev_err(gc->dev, "Failed to request irq %d %s\n",
+			irq, gic->name);
+		kfree(gic);
+		gic = NULL;
+		goto out;
+	}
+
+	refcount_set(&gic->refcount, 1);
+	xa_store(&gc->irq_contexts, msi, gic, GFP_KERNEL);
+
+	if (use_bitmap)
+		set_bit(msi, gc->msi_bitmap);
+
+out:
+	mutex_unlock(&gc->gic_mutex);
+	return gic;
+}
+EXPORT_SYMBOL_NS(gdma_get_gic, "NET_MANA");
+
 int mana_gd_alloc_res_map(u32 res_avail, struct gdma_resource *r)
 {
 	r->map = bitmap_zalloc(res_avail, GFP_KERNEL);
@@ -1856,6 +1979,7 @@ static int mana_gd_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto release_region;
 
 	mutex_init(&gc->eq_test_event_mutex);
+	mutex_init(&gc->gic_mutex);
 	pci_set_drvdata(pdev, gc);
 	gc->bar0_pa = pci_resource_start(pdev, 0);
 

include/net/mana/gdma.h

@@ -363,6 +363,9 @@ struct gdma_irq_context {
 	spinlock_t lock;
 	struct list_head eq_list;
 	char name[MANA_IRQ_NAME_SZ];
+	unsigned int msi;
+	unsigned int irq;
+	refcount_t refcount;
 };
 
 struct gdma_context {
@@ -410,6 +413,7 @@ struct gdma_context {
 	/* Azure RDMA adapter */
 	struct gdma_dev		mana_ib;
 
+	struct mutex		gic_mutex;
 	bool msi_sharing;
 	unsigned long *msi_bitmap;
 };
@@ -905,6 +909,10 @@ int mana_gd_destroy_dma_region(struct gdma_context *gc, u64 dma_region_handle);
 void mana_register_debugfs(void);
 void mana_unregister_debugfs(void);
 
+struct gdma_irq_context *gdma_get_gic(struct gdma_context *gc, bool use_bitmap,
+				      u16 port_index, int queue_index,
+				      int *msi_requested);
+void gdma_put_gic(struct gdma_context *gc, bool use_bitmap, int msi);
 int mana_gd_query_device_cfg(struct gdma_context *gc, u32 proto_major_ver,
 			     u32 proto_minor_ver, u32 proto_micro_ver,
 			     u16 *max_num_vports);