[PATCH] s390: introduce struct subchannel_id

This patch introduces a struct subchannel_id containing the subchannel number
(formerly referred to as "irq") and switches code formerly relying on the
subchannel number over to it.

While we're touching inline assemblies anyway, make sure they have correct
memory constraints.

Signed-off-by: Cornelia Huck <cohuck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 38 insertions, 31 deletions

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 7e4d57b..5137daf 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -33,7 +33,7 @@ struct device css_bus_device = {
 };
 
 static struct subchannel *
-css_alloc_subchannel(int irq)
+css_alloc_subchannel(struct subchannel_id schid)
 {
 	struct subchannel *sch;
 	int ret;
@@ -41,13 +41,11 @@ css_alloc_subchannel(int irq)
 	sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
 	if (sch == NULL)
 		return ERR_PTR(-ENOMEM);
-	ret = cio_validate_subchannel (sch, irq);
+	ret = cio_validate_subchannel (sch, schid);
 	if (ret < 0) {
 		kfree(sch);
 		return ERR_PTR(ret);
 	}
-	if (irq > highest_subchannel)
-		highest_subchannel = irq;
 
 	if (sch->st != SUBCHANNEL_TYPE_IO) {
 		/* For now we ignore all non-io subchannels. */
@@ -87,7 +85,7 @@ css_subchannel_release(struct device *dev)
 	struct subchannel *sch;
 
 	sch = to_subchannel(dev);
-	if (!cio_is_console(sch->irq))
+	if (!cio_is_console(sch->schid))
 		kfree(sch);
 }
 
@@ -114,12 +112,12 @@ css_register_subchannel(struct subchannel *sch)
 }
 
 int
-css_probe_device(int irq)
+css_probe_device(struct subchannel_id schid)
 {
 	int ret;
 	struct subchannel *sch;
 
-	sch = css_alloc_subchannel(irq);
+	sch = css_alloc_subchannel(schid);
 	if (IS_ERR(sch))
 		return PTR_ERR(sch);
 	ret = css_register_subchannel(sch);
@@ -132,26 +130,26 @@ static int
 check_subchannel(struct device * dev, void * data)
 {
 	struct subchannel *sch;
-	int irq = (unsigned long)data;
+	struct subchannel_id *schid = data;
 
 	sch = to_subchannel(dev);
-	return (sch->irq == irq);
+	return schid_equal(&sch->schid, schid);
 }
 
 struct subchannel *
-get_subchannel_by_schid(int irq)
+get_subchannel_by_schid(struct subchannel_id schid)
 {
 	struct device *dev;
 
 	dev = bus_find_device(&css_bus_type, NULL,
-			      (void *)(unsigned long)irq, check_subchannel);
+			      (void *)&schid, check_subchannel);
 
 	return dev ? to_subchannel(dev) : NULL;
 }
 
 
 static inline int
-css_get_subchannel_status(struct subchannel *sch, int schid)
+css_get_subchannel_status(struct subchannel *sch, struct subchannel_id schid)
 {
 	struct schib schib;
 	int cc;
@@ -170,13 +168,13 @@ css_get_subchannel_status(struct subchannel *sch, int schid)
 }
 	
 static int
-css_evaluate_subchannel(int irq, int slow)
+css_evaluate_subchannel(struct subchannel_id schid, int slow)
 {
 	int event, ret, disc;
 	struct subchannel *sch;
 	unsigned long flags;
 
-	sch = get_subchannel_by_schid(irq);
+	sch = get_subchannel_by_schid(schid);
 	disc = sch ? device_is_disconnected(sch) : 0;
 	if (disc && slow) {
 		if (sch)
@@ -194,9 +192,10 @@ css_evaluate_subchannel(int irq, int slow)
 			put_device(&sch->dev);
 		return -EAGAIN; /* Will be done on the slow path. */
 	}
-	event = css_get_subchannel_status(sch, irq);
+	event = css_get_subchannel_status(sch, schid);
 	CIO_MSG_EVENT(4, "Evaluating schid %04x, event %d, %s, %s path.\n",
-		      irq, event, sch?(disc?"disconnected":"normal"):"unknown",
+		      schid.sch_no, event,
+		      sch?(disc?"disconnected":"normal"):"unknown",
 		      slow?"slow":"fast");
 	switch (event) {
 	case CIO_NO_PATH:
@@ -253,7 +252,7 @@ css_evaluate_subchannel(int irq, int slow)
 			sch->schib.pmcw.intparm = 0;
 			cio_modify(sch);
 			put_device(&sch->dev);
-			ret = css_probe_device(irq);
+			ret = css_probe_device(schid);
 		} else {
 			/*
 			 * We can't immediately deregister the disconnected
@@ -272,7 +271,7 @@ css_evaluate_subchannel(int irq, int slow)
 			device_trigger_reprobe(sch);
 			spin_unlock_irqrestore(&sch->lock, flags);
 		}
-		ret = sch ? 0 : css_probe_device(irq);
+		ret = sch ? 0 : css_probe_device(schid);
 		break;
 	default:
 		BUG();
@@ -284,10 +283,12 @@ css_evaluate_subchannel(int irq, int slow)
 static void
 css_rescan_devices(void)
 {
-	int irq, ret;
+	int ret;
+	struct subchannel_id schid;
 
-	for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
-		ret = css_evaluate_subchannel(irq, 1);
+	init_subchannel_id(&schid);
+	do {
+		ret = css_evaluate_subchannel(schid, 1);
 		/* No more memory. It doesn't make sense to continue. No
 		 * panic because this can happen in midflight and just
 		 * because we can't use a new device is no reason to crash
@@ -297,12 +298,12 @@ css_rescan_devices(void)
 		/* -ENXIO indicates that there are no more subchannels. */
 		if (ret == -ENXIO)
 			break;
-	}
+	} while (schid.sch_no++ < __MAX_SUBCHANNEL);
 }
 
 struct slow_subchannel {
 	struct list_head slow_list;
-	unsigned long schid;
+	struct subchannel_id schid;
 };
 
 static LIST_HEAD(slow_subchannels_head);
@@ -357,20 +358,24 @@ int
 css_process_crw(int irq)
 {
 	int ret;
+	struct subchannel_id mchk_schid;
 
 	CIO_CRW_EVENT(2, "source is subchannel %04X\n", irq);
 
 	if (need_rescan)
 		/* We need to iterate all subchannels anyway. */
 		return -EAGAIN;
+
+	init_subchannel_id(&mchk_schid);
+	mchk_schid.sch_no = irq;
 	/* 
 	 * Since we are always presented with IPI in the CRW, we have to
 	 * use stsch() to find out if the subchannel in question has come
 	 * or gone.
 	 */
-	ret = css_evaluate_subchannel(irq, 0);
+	ret = css_evaluate_subchannel(mchk_schid, 0);
 	if (ret == -EAGAIN) {
-		if (css_enqueue_subchannel_slow(irq)) {
+		if (css_enqueue_subchannel_slow(mchk_schid)) {
 			css_clear_subchannel_slow_list();
 			need_rescan = 1;
 		}
@@ -404,7 +409,8 @@ css_generate_pgid(void)
 static int __init
 init_channel_subsystem (void)
 {
-	int ret, irq;
+	int ret;
+	struct subchannel_id schid;
 
 	if (chsc_determine_css_characteristics() == 0)
 		css_characteristics_avail = 1;
@@ -420,13 +426,14 @@ init_channel_subsystem (void)
 
 	ctl_set_bit(6, 28);
 
-	for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
+	init_subchannel_id(&schid);
+	do {
 		struct subchannel *sch;
 
-		if (cio_is_console(irq))
+		if (cio_is_console(schid))
 			sch = cio_get_console_subchannel();
 		else {
-			sch = css_alloc_subchannel(irq);
+			sch = css_alloc_subchannel(schid);
 			if (IS_ERR(sch))
 				ret = PTR_ERR(sch);
 			else
@@ -448,7 +455,7 @@ init_channel_subsystem (void)
 		 * console subchannel.
 		 */
 		css_register_subchannel(sch);
-	}
+	} while (schid.sch_no++ < __MAX_SUBCHANNEL);
 	return 0;
 
 out_bus:
@@ -482,7 +489,7 @@ struct bus_type css_bus_type = {
 subsys_initcall(init_channel_subsystem);
 
 int
-css_enqueue_subchannel_slow(unsigned long schid)
+css_enqueue_subchannel_slow(struct subchannel_id schid)
 {
 	struct slow_subchannel *new_slow_sch;
 	unsigned long flags;