[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>

1 files changed, 58 insertions, 52 deletions

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 5137dafd1e8d..dba632a5f71f 100644
--- a/drivers/s390/cio/css.c
+++ b/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: