s390/irq: use hlists for external interrupt handler array

Use hlists for the hashed array of external interrupt handlers.
Reduces the size of the array by 50% (2KB).

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c
index b34ba0e..4ecf017 100644 (file)
--- a/arch/s390/kernel/irq.c
+++ b/arch/s390/kernel/irq.c
@@ -196,13 +196,13 @@ asmlinkage void do_softirq(void)
  * ext_int_hash[index] is the list head for all external interrupts that hash
  * to this index.
  */
-static struct list_head ext_int_hash[256];
+static struct hlist_head ext_int_hash[256];
 
 struct ext_int_info {
        ext_int_handler_t handler;
-       u16 code;
-       struct list_head entry;
+       struct hlist_node entry;
        struct rcu_head rcu;
+       u16 code;
 };
 
 /* ext_int_hash_lock protects the handler lists for external interrupts */
@@ -227,7 +227,7 @@ int register_external_interrupt(u16 code, ext_int_handler_t handler)
        index = ext_hash(code);
 
        spin_lock_irqsave(&ext_int_hash_lock, flags);
-       list_add_rcu(&p->entry, &ext_int_hash[index]);
+       hlist_add_head_rcu(&p->entry, &ext_int_hash[index]);
        spin_unlock_irqrestore(&ext_int_hash_lock, flags);
        return 0;
 }
@@ -240,9 +240,9 @@ int unregister_external_interrupt(u16 code, ext_int_handler_t handler)
        int index = ext_hash(code);
 
        spin_lock_irqsave(&ext_int_hash_lock, flags);
-       list_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
+       hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
                if (p->code == code && p->handler == handler) {
-                       list_del_rcu(&p->entry);
+                       hlist_del_rcu(&p->entry);
                        kfree_rcu(p, rcu);
                }
        }
@@ -264,12 +264,12 @@ static irqreturn_t do_ext_interrupt(int irq, void *dummy)
 
        index = ext_hash(ext_code.code);
        rcu_read_lock();
-       list_for_each_entry_rcu(p, &ext_int_hash[index], entry)
-               if (likely(p->code == ext_code.code))
-                       p->handler(ext_code, regs->int_parm,
-                                  regs->int_parm_long);
+       hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
+               if (unlikely(p->code != ext_code.code))
+                       continue;
+               p->handler(ext_code, regs->int_parm, regs->int_parm_long);
+       }
        rcu_read_unlock();
-
        return IRQ_HANDLED;
 }
 
@@ -283,7 +283,7 @@ void __init init_ext_interrupts(void)
        int idx;
 
        for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
-               INIT_LIST_HEAD(&ext_int_hash[idx]);
+               INIT_HLIST_HEAD(&ext_int_hash[idx]);
 
        irq_set_chip_and_handler(EXT_INTERRUPT,
                                 &dummy_irq_chip, handle_percpu_irq);