sh: Get rid of the kmem cache code

Unfortunately, at the time during in boot when we want to be setting up
the PMB entries, the kmem subsystem hasn't been initialised.

We now match pmb_map slots with pmb_entry_list slots. When we find an
empty slot in pmb_map, we set the bit, thereby acquiring the
corresponding pmb_entry_list entry. There is a benefit in using this
static array of struct pmb_entry's; we don't need to acquire any locks
in order to traverse the list of struct pmb_entry's.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/mm/pmb.c

@@ -35,7 +35,7 @@
 
 static void __pmb_unmap(struct pmb_entry *);
 
-static struct kmem_cache *pmb_cache;
+static struct pmb_entry pmb_entry_list[NR_PMB_ENTRIES];
 static unsigned long pmb_map;
 
 static struct pmb_entry pmb_init_map[] = {
@@ -73,32 +73,6 @@ static inline unsigned long mk_pmb_data(unsigned int entry)
 	return mk_pmb_entry(entry) | PMB_DATA;
 }
 
-static DEFINE_SPINLOCK(pmb_list_lock);
-static struct pmb_entry *pmb_list;
-
-static inline void pmb_list_add(struct pmb_entry *pmbe)
-{
-	struct pmb_entry **p, *tmp;
-
-	p = &pmb_list;
-	while ((tmp = *p) != NULL)
-		p = &tmp->next;
-
-	pmbe->next = tmp;
-	*p = pmbe;
-}
-
-static inline void pmb_list_del(struct pmb_entry *pmbe)
-{
-	struct pmb_entry **p, *tmp;
-
-	for (p = &pmb_list; (tmp = *p); p = &tmp->next)
-		if (tmp == pmbe) {
-			*p = tmp->next;
-			return;
-		}
-}
-
 static int pmb_alloc_entry(void)
 {
 	unsigned int pos;
@@ -125,7 +99,7 @@ static struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
 	if (pos < 0)
 		return ERR_PTR(pos);
 
-	pmbe = kmem_cache_alloc(pmb_cache, GFP_KERNEL);
+	pmbe = &pmb_entry_list[pos];
 	if (!pmbe)
 		return ERR_PTR(-ENOMEM);
 
@@ -134,20 +108,19 @@ static struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
 	pmbe->flags	= flags;
 	pmbe->entry	= pos;
 
-	spin_lock_irq(&pmb_list_lock);
-	pmb_list_add(pmbe);
-	spin_unlock_irq(&pmb_list_lock);
-
 	return pmbe;
 }
 
 static void pmb_free(struct pmb_entry *pmbe)
 {
-	spin_lock_irq(&pmb_list_lock);
-	pmb_list_del(pmbe);
-	spin_unlock_irq(&pmb_list_lock);
+	int pos = pmbe->entry;
 
-	kmem_cache_free(pmb_cache, pmbe);
+	pmbe->vpn	= 0;
+	pmbe->ppn	= 0;
+	pmbe->flags	= 0;
+	pmbe->entry	= 0;
+
+	clear_bit(pos, &pmb_map);
 }
 
 /*
@@ -202,8 +175,6 @@ static void __uses_jump_to_uncached clear_pmb_entry(struct pmb_entry *pmbe)
 	ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);
 
 	back_to_cached();
-
-	clear_bit(entry, &pmb_map);
 }
 
 
@@ -285,11 +256,16 @@ out:
 
 void pmb_unmap(unsigned long addr)
 {
-	struct pmb_entry **p, *pmbe;
+	struct pmb_entry *pmbe = NULL;
+	int i;
 
-	for (p = &pmb_list; (pmbe = *p); p = &pmbe->next)
-		if (pmbe->vpn == addr)
-			break;
+	for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
+		if (test_bit(i, &pmb_map)) {
+			pmbe = &pmb_entry_list[i];
+			if (pmbe->vpn == addr)
+				break;
+		}
+	}
 
 	if (unlikely(!pmbe))
 		return;
@@ -299,7 +275,7 @@ void pmb_unmap(unsigned long addr)
 
 static void __pmb_unmap(struct pmb_entry *pmbe)
 {
-	WARN_ON(!test_bit(pmbe->entry, &pmb_map));
+	BUG_ON(!test_bit(pmbe->entry, &pmb_map));
 
 	do {
 		struct pmb_entry *pmblink = pmbe;
@@ -322,11 +298,6 @@ static void __pmb_unmap(struct pmb_entry *pmbe)
 	} while (pmbe);
 }
 
-static void pmb_cache_ctor(void *pmb)
-{
-	memset(pmb, 0, sizeof(struct pmb_entry));
-}
-
 int __uses_jump_to_uncached pmb_init(void)
 {
 	unsigned int nr_entries = ARRAY_SIZE(pmb_init_map);
@@ -334,9 +305,6 @@ int __uses_jump_to_uncached pmb_init(void)
 
 	BUG_ON(unlikely(nr_entries >= NR_PMB_ENTRIES));
 
-	pmb_cache = kmem_cache_create("pmb", sizeof(struct pmb_entry), 0,
-				      SLAB_PANIC, pmb_cache_ctor);
-
 	jump_to_uncached();
 
 	/*
@@ -431,15 +399,18 @@ postcore_initcall(pmb_debugfs_init);
 static int pmb_sysdev_suspend(struct sys_device *dev, pm_message_t state)
 {
 	static pm_message_t prev_state;
+	int i;
 
 	/* Restore the PMB after a resume from hibernation */
 	if (state.event == PM_EVENT_ON &&
 	    prev_state.event == PM_EVENT_FREEZE) {
 		struct pmb_entry *pmbe;
-		spin_lock_irq(&pmb_list_lock);
-		for (pmbe = pmb_list; pmbe; pmbe = pmbe->next)
-			set_pmb_entry(pmbe);
-		spin_unlock_irq(&pmb_list_lock);
+		for (i = 0; i < ARRAY_SIZE(pmb_entry_list); i++) {
+			if (test_bit(i, &pmb_map)) {
+				pmbe = &pmb_entry_list[i];
+				set_pmb_entry(pmbe);
+			}
+		}
 	}
 	prev_state = state;
 	return 0;