s390/airq: simplify adapter interrupt code

There are three users of adapter interrupts: AP, QDIO and PCI. Each
registers a single adapter interrupt with independent ISCs. Define
a "struct airq" with the interrupt handler, a pointer and a mask for
the local summary indicator and the ISC for the adapter interrupt
source. Convert the indicator array with its fixed number of adapter
interrupt sources per ISE to an array of hlists. This removes the
limitation to 32 adapter interrupts per ISC and allows for arbitrary
memory locations for the local summary indicator.

Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/airq.h

···
 #ifndef _ASM_S390_AIRQ_H
 #define _ASM_S390_AIRQ_H
 
-typedef void (*adapter_int_handler_t)(void *, void *);
+struct airq_struct {
+	struct hlist_node list;		/* Handler queueing. */
+	void (*handler)(struct airq_struct *);	/* Thin-interrupt handler */
+	u8 *lsi_ptr;			/* Local-Summary-Indicator pointer */
+	u8 lsi_mask;			/* Local-Summary-Indicator mask */
+	u8 isc;				/* Interrupt-subclass */
+	u8 flags;
+};
 
-void *s390_register_adapter_interrupt(adapter_int_handler_t, void *, u8);
-void s390_unregister_adapter_interrupt(void *, u8);
+#define AIRQ_PTR_ALLOCATED	0x01
+
+int register_adapter_interrupt(struct airq_struct *airq);
+void unregister_adapter_interrupt(struct airq_struct *airq);
 
 #endif /* _ASM_S390_AIRQ_H */

arch/s390/pci/pci.c

···
 
 static struct intr_bucket *bucket;
 
-/* Adapter local summary indicator */
-static u8 *zpci_irq_si;
+/* Adapter interrupt definitions */
+static void zpci_irq_handler(struct airq_struct *airq);
+
+static struct airq_struct zpci_airq = {
+	.handler = zpci_irq_handler,
+	.isc = PCI_ISC,
+};
 
 /* I/O Map */
 static DEFINE_SPINLOCK(zpci_iomap_lock);
···
 /* store the last handled bit to implement fair scheduling of devices */
 static DEFINE_PER_CPU(unsigned long, next_sbit);
 
-static void zpci_irq_handler(void *dont, void *need)
+static void zpci_irq_handler(struct airq_struct *airq)
 {
 	unsigned long sbit, mbit, last = 0, start = __get_cpu_var(next_sbit);
 	int rescan = 0, max = aisb_max;
···
 		goto out_alloc;
 	}
 
-	isc_register(PCI_ISC);
-	zpci_irq_si = s390_register_adapter_interrupt(&zpci_irq_handler, NULL, PCI_ISC);
-	if (IS_ERR(zpci_irq_si)) {
-		rc = PTR_ERR(zpci_irq_si);
-		zpci_irq_si = NULL;
+	rc = register_adapter_interrupt(&zpci_airq);
+	if (rc)
 		goto out_ai;
-	}
+	/* Set summary to 1 to be called every time for the ISC. */
+	*zpci_airq.lsi_ptr = 1;
 
 	for_each_online_cpu(cpu)
 		per_cpu(next_sbit, cpu) = 0;
 
 	spin_lock_init(&bucket->lock);
-	/* set summary to 1 to be called every time for the ISC */
-	*zpci_irq_si = 1;
 	set_irq_ctrl(SIC_IRQ_MODE_SINGLE, NULL, PCI_ISC);
 	return 0;
 
 out_ai:
-	isc_unregister(PCI_ISC);
 	free_page((unsigned long) bucket->alloc);
 out_alloc:
 	free_page((unsigned long) bucket->aisb);
···
 {
 	free_page((unsigned long) bucket->alloc);
 	free_page((unsigned long) bucket->aisb);
-	s390_unregister_adapter_interrupt(zpci_irq_si, PCI_ISC);
-	isc_unregister(PCI_ISC);
+	unregister_adapter_interrupt(&zpci_airq);
 	kfree(bucket);
 }
 

drivers/s390/cio/airq.c

···
  */
 
 #include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/kernel_stat.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/rculist.h>
 #include <linux/slab.h>
-#include <linux/rcupdate.h>
 
 #include <asm/airq.h>
 #include <asm/isc.h>
 
 #include "cio.h"
 #include "cio_debug.h"
+#include "ioasm.h"
 
-#define NR_AIRQS		32
-#define NR_AIRQS_PER_WORD	sizeof(unsigned long)
-#define NR_AIRQ_WORDS		(NR_AIRQS / NR_AIRQS_PER_WORD)
-
-union indicator_t {
-	unsigned long word[NR_AIRQ_WORDS];
-	unsigned char byte[NR_AIRQS];
-} __attribute__((packed));
-
-struct airq_t {
-	adapter_int_handler_t handler;
-	void *drv_data;
-};
-
-static union indicator_t indicators[MAX_ISC+1];
-static struct airq_t *airqs[MAX_ISC+1][NR_AIRQS];
-
-static int register_airq(struct airq_t *airq, u8 isc)
-{
-	int i;
-
-	for (i = 0; i < NR_AIRQS; i++)
-		if (!cmpxchg(&airqs[isc][i], NULL, airq))
-			return i;
-	return -ENOMEM;
-}
+static DEFINE_SPINLOCK(airq_lists_lock);
+static struct hlist_head airq_lists[MAX_ISC+1];
 
 /**
- * s390_register_adapter_interrupt() - register adapter interrupt handler
- * @handler: adapter handler to be registered
- * @drv_data: driver data passed with each call to the handler
- * @isc: isc for which the handler should be called
+ * register_adapter_interrupt() - register adapter interrupt handler
+ * @airq: pointer to adapter interrupt descriptor
  *
- * Returns:
- *  Pointer to the indicator to be used on success
- *  ERR_PTR() if registration failed
+ * Returns 0 on success, or -EINVAL.
  */
-void *s390_register_adapter_interrupt(adapter_int_handler_t handler,
-				      void *drv_data, u8 isc)
+int register_adapter_interrupt(struct airq_struct *airq)
 {
-	struct airq_t *airq;
-	char dbf_txt[16];
-	int ret;
+	char dbf_txt[32];
 
-	if (isc > MAX_ISC)
-		return ERR_PTR(-EINVAL);
-	airq = kmalloc(sizeof(struct airq_t), GFP_KERNEL);
-	if (!airq) {
-		ret = -ENOMEM;
-		goto out;
+	if (!airq->handler || airq->isc > MAX_ISC)
+		return -EINVAL;
+	if (!airq->lsi_ptr) {
+		airq->lsi_ptr = kzalloc(1, GFP_KERNEL);
+		if (!airq->lsi_ptr)
+			return -ENOMEM;
+		airq->flags |= AIRQ_PTR_ALLOCATED;
 	}
-	airq->handler = handler;
-	airq->drv_data = drv_data;
-
-	ret = register_airq(airq, isc);
-out:
-	snprintf(dbf_txt, sizeof(dbf_txt), "rairq:%d", ret);
+	if (!airq->lsi_mask)
+		airq->lsi_mask = 0xff;
+	snprintf(dbf_txt, sizeof(dbf_txt), "rairq:%p", airq);
 	CIO_TRACE_EVENT(4, dbf_txt);
-	if (ret < 0) {
-		kfree(airq);
-		return ERR_PTR(ret);
-	} else
-		return &indicators[isc].byte[ret];
+	isc_register(airq->isc);
+	spin_lock(&airq_lists_lock);
+	hlist_add_head_rcu(&airq->list, &airq_lists[airq->isc]);
+	spin_unlock(&airq_lists_lock);
+	return 0;
 }
-EXPORT_SYMBOL(s390_register_adapter_interrupt);
+EXPORT_SYMBOL(register_adapter_interrupt);
 
 /**
- * s390_unregister_adapter_interrupt - unregister adapter interrupt handler
- * @ind: indicator for which the handler is to be unregistered
- * @isc: interruption subclass
+ * unregister_adapter_interrupt - unregister adapter interrupt handler
+ * @airq: pointer to adapter interrupt descriptor
  */
-void s390_unregister_adapter_interrupt(void *ind, u8 isc)
+void unregister_adapter_interrupt(struct airq_struct *airq)
 {
-	struct airq_t *airq;
-	char dbf_txt[16];
-	int i;
+	char dbf_txt[32];
 
-	i = (int) ((addr_t) ind) - ((addr_t) &indicators[isc].byte[0]);
-	snprintf(dbf_txt, sizeof(dbf_txt), "urairq:%d", i);
+	if (hlist_unhashed(&airq->list))
+		return;
+	snprintf(dbf_txt, sizeof(dbf_txt), "urairq:%p", airq);
 	CIO_TRACE_EVENT(4, dbf_txt);
-	indicators[isc].byte[i] = 0;
-	airq = xchg(&airqs[isc][i], NULL);
-	/*
-	 * Allow interrupts to complete. This will ensure that the airq handle
-	 * is no longer referenced by any interrupt handler.
-	 */
-	synchronize_sched();
-	kfree(airq);
+	spin_lock(&airq_lists_lock);
+	hlist_del_rcu(&airq->list);
+	spin_unlock(&airq_lists_lock);
+	synchronize_rcu();
+	isc_unregister(airq->isc);
+	if (airq->flags & AIRQ_PTR_ALLOCATED) {
+		kfree(airq->lsi_ptr);
+		airq->lsi_ptr = NULL;
+		airq->flags &= ~AIRQ_PTR_ALLOCATED;
+	}
 }
-EXPORT_SYMBOL(s390_unregister_adapter_interrupt);
-
-#define INDICATOR_MASK	(0xffUL << ((NR_AIRQS_PER_WORD - 1) * 8))
+EXPORT_SYMBOL(unregister_adapter_interrupt);
 
 void do_adapter_IO(u8 isc)
 {
-	int w;
-	int i;
-	unsigned long word;
-	struct airq_t *airq;
+	struct airq_struct *airq;
+	struct hlist_head *head;
 
-	/*
-	 * Access indicator array in word-sized chunks to minimize storage
-	 * fetch operations.
-	 */
-	for (w = 0; w < NR_AIRQ_WORDS; w++) {
-		word = indicators[isc].word[w];
-		i = w * NR_AIRQS_PER_WORD;
-		/*
-		 * Check bytes within word for active indicators.
-		 */
-		while (word) {
-			if (word & INDICATOR_MASK) {
-				airq = airqs[isc][i];
-				/* Make sure gcc reads from airqs only once. */
-				barrier();
-				if (likely(airq))
-					airq->handler(&indicators[isc].byte[i],
-						      airq->drv_data);
-				else
-					/*
-					 * Reset ill-behaved indicator.
-					 */
-					indicators[isc].byte[i] = 0;
-			}
-			word <<= 8;
-			i++;
-		}
-	}
+	head = &airq_lists[isc];
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(airq, head, list)
+		if ((*airq->lsi_ptr & airq->lsi_mask) != 0)
+			airq->handler(airq);
+	rcu_read_unlock();
 }

drivers/s390/cio/qdio_thinint.c

···
 static LIST_HEAD(tiq_list);
 static DEFINE_MUTEX(tiq_list_lock);
 
-/* adapter local summary indicator */
-static u8 *tiqdio_alsi;
+/* Adapter interrupt definitions */
+static void tiqdio_thinint_handler(struct airq_struct *airq);
+
+static struct airq_struct tiqdio_airq = {
+	.handler = tiqdio_thinint_handler,
+	.isc = QDIO_AIRQ_ISC,
+};
 
 static struct indicator_t *q_indicators;
 
···
  * @alsi: pointer to adapter local summary indicator
  * @data: NULL
  */
-static void tiqdio_thinint_handler(void *alsi, void *data)
+static void tiqdio_thinint_handler(struct airq_struct *airq)
 {
 	u32 si_used = clear_shared_ind();
 	struct qdio_q *q;
···
 		summary_indicator_addr = 0;
 		subchannel_indicator_addr = 0;
 	} else {
-		summary_indicator_addr = virt_to_phys(tiqdio_alsi);
+		summary_indicator_addr = virt_to_phys(tiqdio_airq.lsi_ptr);
 		subchannel_indicator_addr = virt_to_phys(irq_ptr->dsci);
 	}
 
···
 
 int __init tiqdio_register_thinints(void)
 {
-	isc_register(QDIO_AIRQ_ISC);
-	tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
-						      NULL, QDIO_AIRQ_ISC);
-	if (IS_ERR(tiqdio_alsi)) {
-		DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
-		tiqdio_alsi = NULL;
-		isc_unregister(QDIO_AIRQ_ISC);
-		return -ENOMEM;
+	int rc;
+
+	rc = register_adapter_interrupt(&tiqdio_airq);
+	if (rc) {
+		DBF_EVENT("RTI:%x", rc);
+		return rc;
 	}
 	return 0;
 }
···
 void __exit tiqdio_unregister_thinints(void)
 {
 	WARN_ON(!list_empty(&tiq_list));
-
-	if (tiqdio_alsi) {
-		s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
-		isc_unregister(QDIO_AIRQ_ISC);
-	}
+	unregister_adapter_interrupt(&tiqdio_airq);
 }

drivers/s390/crypto/ap_bus.c

···
 static int __ap_poll_device(struct ap_device *ap_dev, unsigned long *flags);
 static int ap_device_remove(struct device *dev);
 static int ap_device_probe(struct device *dev);
-static void ap_interrupt_handler(void *unused1, void *unused2);
+static void ap_interrupt_handler(struct airq_struct *airq);
 static void ap_reset(struct ap_device *ap_dev);
 static void ap_config_timeout(unsigned long ptr);
 static int ap_select_domain(void);
···
 static struct task_struct *ap_poll_kthread = NULL;
 static DEFINE_MUTEX(ap_poll_thread_mutex);
 static DEFINE_SPINLOCK(ap_poll_timer_lock);
-static void *ap_interrupt_indicator;
 static struct hrtimer ap_poll_timer;
 /* In LPAR poll with 4kHz frequency. Poll every 250000 nanoseconds.
  * If z/VM change to 1500000 nanoseconds to adjust to z/VM polling.*/
···
 static int user_set_domain = 0;
 static struct bus_type ap_bus_type;
 
+/* Adapter interrupt definitions */
+static int ap_airq_flag;
+
+static struct airq_struct ap_airq = {
+	.handler = ap_interrupt_handler,
+	.isc = AP_ISC,
+};
+
 /**
  * ap_using_interrupts() - Returns non-zero if interrupt support is
  * available.
  */
 static inline int ap_using_interrupts(void)
 {
-	return ap_interrupt_indicator != NULL;
+	return ap_airq_flag;
 }
 
 /**
···
 		}
 	}
 	if (rc == 0 && ap_using_interrupts()) {
-		rc = ap_queue_enable_interruption(qid, ap_interrupt_indicator);
+		rc = ap_queue_enable_interruption(qid, ap_airq.lsi_ptr);
 		/* If interruption mode is supported by the machine,
 		* but an AP can not be enabled for interruption then
 		* the AP will be discarded.    */
···
 
 static int ap_bus_resume(struct device *dev)
 {
-	int rc = 0;
 	struct ap_device *ap_dev = to_ap_dev(dev);
+	int rc;
 
 	if (ap_suspend_flag) {
 		ap_suspend_flag = 0;
-		if (!ap_interrupts_available())
-			ap_interrupt_indicator = NULL;
+		if (ap_interrupts_available()) {
+			if (!ap_using_interrupts()) {
+				rc = register_adapter_interrupt(&ap_airq);
+				ap_airq_flag = (rc == 0);
+			}
+		} else {
+			if (ap_using_interrupts()) {
+				unregister_adapter_interrupt(&ap_airq);
+				ap_airq_flag = 0;
+			}
+		}
 		ap_query_configuration();
 		if (!user_set_domain) {
 			ap_domain_index = -1;
···
 			tasklet_schedule(&ap_tasklet);
 		if (ap_thread_flag)
 			rc = ap_poll_thread_start();
-	}
+		else
+			rc = 0;
+	} else
+		rc = 0;
 	if (AP_QID_QUEUE(ap_dev->qid) != ap_domain_index) {
 		spin_lock_bh(&ap_dev->lock);
 		ap_dev->qid = AP_MKQID(AP_QID_DEVICE(ap_dev->qid),
···
 	return rc;
 }
 
-static void ap_interrupt_handler(void *unused1, void *unused2)
+static void ap_interrupt_handler(struct airq_struct *airq)
 {
 	inc_irq_stat(IRQIO_APB);
 	tasklet_schedule(&ap_tasklet);
···
 	 * important that no requests on any AP get lost.
 	 */
 	if (ap_using_interrupts())
-		xchg((u8 *)ap_interrupt_indicator, 0);
+		xchg(ap_airq.lsi_ptr, 0);
 	do {
 		flags = 0;
 		spin_lock(&ap_device_list_lock);
···
 		return -ENODEV;
 	}
 	if (ap_interrupts_available()) {
-		isc_register(AP_ISC);
-		ap_interrupt_indicator = s390_register_adapter_interrupt(
-			&ap_interrupt_handler, NULL, AP_ISC);
-		if (IS_ERR(ap_interrupt_indicator)) {
-			ap_interrupt_indicator = NULL;
-			isc_unregister(AP_ISC);
-		}
+		rc = register_adapter_interrupt(&ap_airq);
+		ap_airq_flag = (rc == 0);
 	}
 
 	register_reset_call(&ap_reset_call);
···
 	bus_unregister(&ap_bus_type);
 out:
 	unregister_reset_call(&ap_reset_call);
-	if (ap_using_interrupts()) {
-		s390_unregister_adapter_interrupt(ap_interrupt_indicator, AP_ISC);
-		isc_unregister(AP_ISC);
-	}
+	if (ap_using_interrupts())
+		unregister_adapter_interrupt(&ap_airq);
 	return rc;
 }
 
···
 		bus_remove_file(&ap_bus_type, ap_bus_attrs[i]);
 	bus_unregister(&ap_bus_type);
 	unregister_reset_call(&ap_reset_call);
-	if (ap_using_interrupts()) {
-		s390_unregister_adapter_interrupt(ap_interrupt_indicator, AP_ISC);
-		isc_unregister(AP_ISC);
-	}
+	if (ap_using_interrupts())
+		unregister_adapter_interrupt(&ap_airq);
 }
 
 module_init(ap_module_init);