1 files changed, 47 insertions, 101 deletions

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index fe0ace7aece..fcc641e578f 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -20,8 +20,8 @@
 #include "ioasm.h"
 #include "chsc.h"
 #include "device.h"
+#include "idset.h"
 
-int need_rescan = 0;
 int css_init_done = 0;
 static int need_reprobe = 0;
 static int max_ssid = 0;
@@ -306,7 +306,7 @@ static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
         return css_probe_device(schid);
 }
 
-static int css_evaluate_subchannel(struct subchannel_id schid, int slow)
+static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 {
         struct subchannel *sch;
         int ret;
@@ -317,53 +317,66 @@ static int css_evaluate_subchannel(struct subchannel_id schid, int slow)
                 put_device(&sch->dev);
         } else
                 ret = css_evaluate_new_subchannel(schid, slow);
-
-        return ret;
+        if (ret == -EAGAIN)
+                css_schedule_eval(schid);
 }
 
-static int
-css_rescan_devices(struct subchannel_id schid, void *data)
+static struct idset *slow_subchannel_set;
+static spinlock_t slow_subchannel_lock;
+
+static int __init slow_subchannel_init(void)
 {
-        return css_evaluate_subchannel(schid, 1);
+        spin_lock_init(&slow_subchannel_lock);
+        slow_subchannel_set = idset_sch_new();
+        if (!slow_subchannel_set) {
+                printk(KERN_WARNING "cio: could not allocate slow subchannel "
+                       "set\n");
+                return -ENOMEM;
+        }
+        return 0;
 }
 
-struct slow_subchannel {
-        struct list_head slow_list;
-        struct subchannel_id schid;
-};
-
-static LIST_HEAD(slow_subchannels_head);
-static DEFINE_SPINLOCK(slow_subchannel_lock);
+subsys_initcall(slow_subchannel_init);
 
-static void
-css_trigger_slow_path(struct work_struct *unused)
+static void css_slow_path_func(struct work_struct *unused)
 {
-        CIO_TRACE_EVENT(4, "slowpath");
-
-        if (need_rescan) {
-                need_rescan = 0;
-                for_each_subchannel(css_rescan_devices, NULL);
-                return;
-        }
+        struct subchannel_id schid;
 
+        CIO_TRACE_EVENT(4, "slowpath");
         spin_lock_irq(&slow_subchannel_lock);
-        while (!list_empty(&slow_subchannels_head)) {
-                struct slow_subchannel *slow_sch =
-                        list_entry(slow_subchannels_head.next,
-                                   struct slow_subchannel, slow_list);
-
-                list_del_init(slow_subchannels_head.next);
+        init_subchannel_id(&schid);
+        while (idset_sch_get_first(slow_subchannel_set, &schid)) {
+                idset_sch_del(slow_subchannel_set, schid);
                 spin_unlock_irq(&slow_subchannel_lock);
-                css_evaluate_subchannel(slow_sch->schid, 1);
+                css_evaluate_subchannel(schid, 1);
                 spin_lock_irq(&slow_subchannel_lock);
-                kfree(slow_sch);
         }
         spin_unlock_irq(&slow_subchannel_lock);
 }
 
-DECLARE_WORK(slow_path_work, css_trigger_slow_path);
+static DECLARE_WORK(slow_path_work, css_slow_path_func);
 struct workqueue_struct *slow_path_wq;
 
+void css_schedule_eval(struct subchannel_id schid)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&slow_subchannel_lock, flags);
+        idset_sch_add(slow_subchannel_set, schid);
+        queue_work(slow_path_wq, &slow_path_work);
+        spin_unlock_irqrestore(&slow_subchannel_lock, flags);
+}
+
+void css_schedule_eval_all(void)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&slow_subchannel_lock, flags);
+        idset_fill(slow_subchannel_set);
+        queue_work(slow_path_wq, &slow_path_work);
+        spin_unlock_irqrestore(&slow_subchannel_lock, flags);
+}
+
 /* Reprobe subchannel if unregistered. */
 static int reprobe_subchannel(struct subchannel_id schid, void *data)
 {
@@ -426,33 +439,14 @@ void css_schedule_reprobe(void)
 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 
 /*
- * Rescan for new devices. FIXME: This is slow.
- * This function is called when we have lost CRWs due to overflows and we have
- * to do subchannel housekeeping.
- */
-void
-css_reiterate_subchannels(void)
-{
-        css_clear_subchannel_slow_list();
-        need_rescan = 1;
-}
-
-/*
  * Called from the machine check handler for subchannel report words.
  */
-int
-css_process_crw(int rsid1, int rsid2)
+void css_process_crw(int rsid1, int rsid2)
 {
-        int ret;
         struct subchannel_id mchk_schid;
 
         CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
                       rsid1, rsid2);
-
-        if (need_rescan)
-                /* We need to iterate all subchannels anyway. */
-                return -EAGAIN;
-
         init_subchannel_id(&mchk_schid);
         mchk_schid.sch_no = rsid1;
         if (rsid2 != 0)
@@ -463,14 +457,7 @@ css_process_crw(int rsid1, int rsid2)
          * use stsch() to find out if the subchannel in question has come
          * or gone.
          */
-        ret = css_evaluate_subchannel(mchk_schid, 0);
-        if (ret == -EAGAIN) {
-                if (css_enqueue_subchannel_slow(mchk_schid)) {
-                        css_clear_subchannel_slow_list();
-                        need_rescan = 1;
-                }
-        }
-        return ret;
+        css_evaluate_subchannel(mchk_schid, 0);
 }
 
 static int __init
@@ -745,47 +732,6 @@ struct bus_type css_bus_type = {
 
 subsys_initcall(init_channel_subsystem);
 
-int
-css_enqueue_subchannel_slow(struct subchannel_id schid)
-{
-        struct slow_subchannel *new_slow_sch;
-        unsigned long flags;
-
-        new_slow_sch = kzalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
-        if (!new_slow_sch)
-                return -ENOMEM;
-        new_slow_sch->schid = schid;
-        spin_lock_irqsave(&slow_subchannel_lock, flags);
-        list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
-        spin_unlock_irqrestore(&slow_subchannel_lock, flags);
-        return 0;
-}
-
-void
-css_clear_subchannel_slow_list(void)
-{
-        unsigned long flags;
-
-        spin_lock_irqsave(&slow_subchannel_lock, flags);
-        while (!list_empty(&slow_subchannels_head)) {
-                struct slow_subchannel *slow_sch =
-                        list_entry(slow_subchannels_head.next,
-                                   struct slow_subchannel, slow_list);
-
-                list_del_init(slow_subchannels_head.next);
-                kfree(slow_sch);
-        }
-        spin_unlock_irqrestore(&slow_subchannel_lock, flags);
-}
-
-
-
-int
-css_slow_subchannels_exist(void)
-{
-        return (!list_empty(&slow_subchannels_head));
-}
-
 MODULE_LICENSE("GPL");
 EXPORT_SYMBOL(css_bus_type);
 EXPORT_SYMBOL_GPL(css_characteristics_avail);