On Tue, 19 Jul 2016, Eric Auger wrote:

+
+#include <linux/slab.h>
+#include <linux/irq.h>
+#include <linux/msi-doorbell.h>
+
+struct irqchip_doorbell {
+	struct irq_chip_msi_doorbell_info info;
+	struct list_head next;

Again, please align the struct members.

+};
+
+static LIST_HEAD(irqchip_doorbell_list);
+static DEFINE_MUTEX(irqchip_doorbell_mutex);
+
+struct irq_chip_msi_doorbell_info *
+msi_doorbell_register_global(phys_addr_t base, size_t size,
+			     int prot, bool irq_remapping)
+{
+	struct irqchip_doorbell *db;
+
+	db = kmalloc(sizeof(*db), GFP_KERNEL);
+	if (!db)
+		return ERR_PTR(-ENOMEM);
+
+	db->info.doorbell_is_percpu = false;

Please use kzalloc and get rid of zero initialization. If you add stuff to the
struct then initialization will be automatically 0.

+void msi_doorbell_unregister_global(struct irq_chip_msi_doorbell_info *dbinfo)
+{
+	struct irqchip_doorbell *db, *tmp;
+
+	mutex_lock(&irqchip_doorbell_mutex);
+	list_for_each_entry_safe(db, tmp, &irqchip_doorbell_list, next) {

Why do you need that iterator? 

    db = container_of(dbinfo, struct ....., info);

Hmm?

+		if (dbinfo == &db->info) {
+			list_del(&db->next);
+			kfree(db);

Please move the kfree() outside of the lock region. It does not matter much
here, but we really should stop doing random crap in locked regions.

Thanks,

	tglx