[PATCH] s390: introduce for_each_subchannel

for_each_subchannel() is an iterator calling a function for every possible
subchannel id until non-zero is returned.  Convert the current iterating
functions to it.
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>

drivers/s390/cio/blacklist.c

@@ -219,6 +219,27 @@ is_blacklisted (int devno)
 }
 
 #ifdef CONFIG_PROC_FS
+static int
+__s390_redo_validation(struct subchannel_id schid, void *data)
+{
+	int ret;
+	struct subchannel *sch;
+
+	sch = get_subchannel_by_schid(schid);
+	if (sch) {
+		/* Already known. */
+		put_device(&sch->dev);
+		return 0;
+	}
+	ret = css_probe_device(schid);
+	if (ret == -ENXIO)
+		return ret; /* We're through. */
+	if (ret == -ENOMEM)
+		/* Stop validation for now. Bad, but no need for a panic. */
+		return ret;
+	return 0;
+}
+
 /*
  * Function: s390_redo_validation
  * Look for no longer blacklisted devices
@@ -226,30 +247,9 @@ is_blacklisted (int devno)
 static inline void
 s390_redo_validation (void)
 {
-	struct subchannel_id schid;
-
 	CIO_TRACE_EVENT (0, "redoval");
-	init_subchannel_id(&schid);
-	do {
-		int ret;
-		struct subchannel *sch;
-
-		sch = get_subchannel_by_schid(schid);
-		if (sch) {
-			/* Already known. */
-			put_device(&sch->dev);
-			continue;
-		}
-		ret = css_probe_device(schid);
-		if (ret == -ENXIO)
-			break; /* We're through. */
-		if (ret == -ENOMEM)
-			/*
-			 * Stop validation for now. Bad, but no need for a
-			 * panic.
-			 */
-			break;
-	} while (schid.sch_no++ < __MAX_SUBCHANNEL);
+
+	for_each_subchannel(__s390_redo_validation, NULL);
 }
 
 /*

drivers/s390/cio/cio.c

@@ -691,7 +691,22 @@ wait_cons_dev (void)
 }
 
 static int
-cio_console_irq(void)
+cio_test_for_console(struct subchannel_id schid, void *data)
+{
+	if (stsch(schid, &console_subchannel.schib) != 0)
+		return -ENXIO;
+	if (console_subchannel.schib.pmcw.dnv &&
+	    console_subchannel.schib.pmcw.dev ==
+	    console_devno) {
+		console_irq = schid.sch_no;
+		return 1; /* found */
+	}
+	return 0;
+}
+
+
+static int
+cio_get_console_sch_no(void)
 {
 	struct subchannel_id schid;
 	
@@ -705,16 +720,7 @@ cio_console_irq(void)
 		console_devno = console_subchannel.schib.pmcw.dev;
 	} else if (console_devno != -1) {
 		/* At least the console device number is known. */
-		do {
-			if (stsch(schid, &console_subchannel.schib) != 0)
-				break;
-			if (console_subchannel.schib.pmcw.dnv &&
-			    console_subchannel.schib.pmcw.dev ==
-			    console_devno) {
-				console_irq = schid.sch_no;
-				break;
-			}
-		} while (schid.sch_no++ < __MAX_SUBCHANNEL);
+		for_each_subchannel(cio_test_for_console, NULL);
 		if (console_irq == -1)
 			return -1;
 	} else {
@@ -730,19 +736,19 @@ cio_console_irq(void)
 struct subchannel *
 cio_probe_console(void)
 {
-	int irq, ret;
+	int sch_no, ret;
 	struct subchannel_id schid;
 
 	if (xchg(&console_subchannel_in_use, 1) != 0)
 		return ERR_PTR(-EBUSY);
-	irq = cio_console_irq();
-	if (irq == -1) {
+	sch_no = cio_get_console_sch_no();
+	if (sch_no == -1) {
 		console_subchannel_in_use = 0;
 		return ERR_PTR(-ENODEV);
 	}
 	memset(&console_subchannel, 0, sizeof(struct subchannel));
 	init_subchannel_id(&schid);
-	schid.sch_no = irq;
+	schid.sch_no = sch_no;
 	ret = cio_validate_subchannel(&console_subchannel, schid);
 	if (ret) {
 		console_subchannel_in_use = 0;
@@ -830,32 +836,33 @@ __clear_subchannel_easy(struct subchannel_id schid)
 }
 
 extern void do_reipl(unsigned long devno);
+static int
+__shutdown_subchannel_easy(struct subchannel_id schid, void *data)
+{
+	struct schib schib;
+
+	if (stsch(schid, &schib))
+		return -ENXIO;
+	if (!schib.pmcw.ena)
+		return 0;
+	switch(__disable_subchannel_easy(schid, &schib)) {
+	case 0:
+	case -ENODEV:
+		break;
+	default: /* -EBUSY */
+		if (__clear_subchannel_easy(schid))
+			break; /* give up... */
+		stsch(schid, &schib);
+		__disable_subchannel_easy(schid, &schib);
+	}
+	return 0;
+}
 
-/* Clear all subchannels. */
 void
 clear_all_subchannels(void)
 {
-	struct subchannel_id schid;
-
 	local_irq_disable();
-	init_subchannel_id(&schid);
-	do {
-		struct schib schib;
-		if (stsch(schid, &schib))
-			break; /* break out of the loop */
-		if (!schib.pmcw.ena)
-			continue;
-		switch(__disable_subchannel_easy(schid, &schib)) {
-		case 0:
-		case -ENODEV:
-			break;
-		default: /* -EBUSY */
-			if (__clear_subchannel_easy(schid))
-				break; /* give up... jump out of switch */
-			stsch(schid, &schib);
-			__disable_subchannel_easy(schid, &schib);
-		}
-	} while (schid.sch_no++ < __MAX_SUBCHANNEL);
+	for_each_subchannel(__shutdown_subchannel_easy, NULL);
 }
 
 /* Make sure all subchannels are quiet before we re-ipl an lpar. */

drivers/s390/cio/css.c

@@ -21,7 +21,6 @@
 #include "ioasm.h"
 #include "chsc.h"
 
-unsigned int highest_subchannel;
 int need_rescan = 0;
 int css_init_done = 0;
 
@@ -32,6 +31,22 @@ struct device css_bus_device = {
 	.bus_id = "css0",
 };
 
+inline int
+for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
+{
+	struct subchannel_id schid;
+	int ret;
+
+	init_subchannel_id(&schid);
+	ret = -ENODEV;
+	do {
+		ret = fn(schid, data);
+		if (ret)
+			break;
+	} while (schid.sch_no++ < __MAX_SUBCHANNEL);
+	return ret;
+}
+
 static struct subchannel *
 css_alloc_subchannel(struct subchannel_id schid)
 {
@@ -280,25 +295,10 @@ css_evaluate_subchannel(struct subchannel_id schid, int slow)
 	return ret;
 }
 
-static void
-css_rescan_devices(void)
+static int
+css_rescan_devices(struct subchannel_id schid, void *data)
 {
-	int ret;
-	struct subchannel_id schid;
-
-	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
-		 * the system. */
-		if (ret == -ENOMEM)
-			break;
-		/* -ENXIO indicates that there are no more subchannels. */
-		if (ret == -ENXIO)
-			break;
-	} while (schid.sch_no++ < __MAX_SUBCHANNEL);
+	return css_evaluate_subchannel(schid, 1);
 }
 
 struct slow_subchannel {
@@ -316,7 +316,7 @@ css_trigger_slow_path(void)
 
 	if (need_rescan) {
 		need_rescan = 0;
-		css_rescan_devices();
+		for_each_subchannel(css_rescan_devices, NULL);
 		return;
 	}
 
@@ -383,6 +383,43 @@ css_process_crw(int irq)
 	return ret;
 }
 
+static int __init
+__init_channel_subsystem(struct subchannel_id schid, void *data)
+{
+	struct subchannel *sch;
+	int ret;
+
+	if (cio_is_console(schid))
+		sch = cio_get_console_subchannel();
+	else {
+		sch = css_alloc_subchannel(schid);
+		if (IS_ERR(sch))
+			ret = PTR_ERR(sch);
+		else
+			ret = 0;
+		switch (ret) {
+		case 0:
+			break;
+		case -ENOMEM:
+			panic("Out of memory in init_channel_subsystem\n");
+		/* -ENXIO: no more subchannels. */
+		case -ENXIO:
+			return ret;
+		default:
+			return 0;
+		}
+	}
+	/*
+	 * We register ALL valid subchannels in ioinfo, even those
+	 * that have been present before init_channel_subsystem.
+	 * These subchannels can't have been registered yet (kmalloc
+	 * not working) so we do it now. This is true e.g. for the
+	 * console subchannel.
+	 */
+	css_register_subchannel(sch);
+	return 0;
+}
+
 static void __init
 css_generate_pgid(void)
 {
@@ -410,7 +447,6 @@ static int __init
 init_channel_subsystem (void)
 {
 	int ret;
-	struct subchannel_id schid;
 
 	if (chsc_determine_css_characteristics() == 0)
 		css_characteristics_avail = 1;
@@ -426,38 +462,8 @@ init_channel_subsystem (void)
 
 	ctl_set_bit(6, 28);
 
-	init_subchannel_id(&schid);
-	do {
-		struct subchannel *sch;
-
-		if (cio_is_console(schid))
-			sch = cio_get_console_subchannel();
-		else {
-			sch = css_alloc_subchannel(schid);
-			if (IS_ERR(sch))
-				ret = PTR_ERR(sch);
-			else
-				ret = 0;
-			if (ret == -ENOMEM)
-				panic("Out of memory in "
-				      "init_channel_subsystem\n");
-			/* -ENXIO: no more subchannels. */
-			if (ret == -ENXIO)
-				break;
-			if (ret)
-				continue;
-		}
-		/*
-		 * We register ALL valid subchannels in ioinfo, even those
-		 * that have been present before init_channel_subsystem.
-		 * These subchannels can't have been registered yet (kmalloc
-		 * not working) so we do it now. This is true e.g. for the
-		 * console subchannel.
-		 */
-		css_register_subchannel(sch);
-	} while (schid.sch_no++ < __MAX_SUBCHANNEL);
+	for_each_subchannel(__init_channel_subsystem, NULL);
 	return 0;
-
 out_bus:
 	bus_unregister(&css_bus_type);
 out:

drivers/s390/cio/css.h

@@ -126,6 +126,7 @@ extern struct css_driver io_subchannel_driver;
 extern int css_probe_device(struct subchannel_id);
 extern struct subchannel * get_subchannel_by_schid(struct subchannel_id);
 extern int css_init_done;
+extern int for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *);
 
 #define __MAX_SUBCHANNEL 65535