kobject: convert hvc_console to use kref, not kobject

hvc_console is using a kobject only for reference counting, nothing
else.  So switch it to use a kref instead, which is all that is needed,
and is much smaller.

Cc: Anton Blanchard <anton@au.ibm.com>
Cc: Paul Mackerras <paulus@au.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ryan S. Arnold <rsa@us.ibm.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 33 insertions, 47 deletions

diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index 8252f8668538..480fae29c9b2 100644
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -27,7 +27,7 @@
 #include <linux/init.h>
 #include <linux/kbd_kern.h>
 #include <linux/kernel.h>
-#include <linux/kobject.h>
+#include <linux/kref.h>
 #include <linux/kthread.h>
 #include <linux/list.h>
 #include <linux/module.h>
@@ -89,7 +89,7 @@ struct hvc_struct {
         int irq_requested;
         int irq;
         struct list_head next;
-        struct kobject kobj; /* ref count & hvc_struct lifetime */
+        struct kref kref; /* ref count & hvc_struct lifetime */
 };
 
 /* dynamic list of hvc_struct instances */
@@ -110,7 +110,7 @@ static int last_hvc = -1;
 
 /*
  * Do not call this function with either the hvc_structs_lock or the hvc_struct
- * lock held.  If successful, this function increments the kobject reference
+ * lock held.  If successful, this function increments the kref reference
  * count against the target hvc_struct so it should be released when finished.
  */
 static struct hvc_struct *hvc_get_by_index(int index)
@@ -123,7 +123,7 @@ static struct hvc_struct *hvc_get_by_index(int index)
         list_for_each_entry(hp, &hvc_structs, next) {
                 spin_lock_irqsave(&hp->lock, flags);
                 if (hp->index == index) {
-                        kobject_get(&hp->kobj);
+                        kref_get(&hp->kref);
                         spin_unlock_irqrestore(&hp->lock, flags);
                         spin_unlock(&hvc_structs_lock);
                         return hp;
@@ -242,6 +242,23 @@ static int __init hvc_console_init(void)
 }
 console_initcall(hvc_console_init);
 
+/* callback when the kboject ref count reaches zero. */
+static void destroy_hvc_struct(struct kref *kref)
+{
+        struct hvc_struct *hp = container_of(kref, struct hvc_struct, kref);
+        unsigned long flags;
+
+        spin_lock(&hvc_structs_lock);
+
+        spin_lock_irqsave(&hp->lock, flags);
+        list_del(&(hp->next));
+        spin_unlock_irqrestore(&hp->lock, flags);
+
+        spin_unlock(&hvc_structs_lock);
+
+        kfree(hp);
+}
+
 /*
  * hvc_instantiate() is an early console discovery method which locates
  * consoles * prior to the vio subsystem discovering them.  Hotplugged
@@ -261,7 +278,7 @@ int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops)
         /* make sure no no tty has been registered in this index */
         hp = hvc_get_by_index(index);
         if (hp) {
-                kobject_put(&hp->kobj);
+                kref_put(&hp->kref, destroy_hvc_struct);
                 return -1;
         }
 
@@ -318,9 +335,8 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
         unsigned long flags;
         int irq = 0;
         int rc = 0;
-        struct kobject *kobjp;
 
-        /* Auto increments kobject reference if found. */
+        /* Auto increments kref reference if found. */
         if (!(hp = hvc_get_by_index(tty->index)))
                 return -ENODEV;
 
@@ -341,8 +357,6 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
         if (irq)
                 hp->irq_requested = 1;
 
-        kobjp = &hp->kobj;
-
         spin_unlock_irqrestore(&hp->lock, flags);
         /* check error, fallback to non-irq */
         if (irq)
@@ -352,7 +366,7 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
          * If the request_irq() fails and we return an error.  The tty layer
          * will call hvc_close() after a failed open but we don't want to clean
          * up there so we'll clean up here and clear out the previously set
-         * tty fields and return the kobject reference.
+         * tty fields and return the kref reference.
          */
         if (rc) {
                 spin_lock_irqsave(&hp->lock, flags);
@@ -360,7 +374,7 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
                 hp->irq_requested = 0;
                 spin_unlock_irqrestore(&hp->lock, flags);
                 tty->driver_data = NULL;
-                kobject_put(kobjp);
+                kref_put(&hp->kref, destroy_hvc_struct);
                 printk(KERN_ERR "hvc_open: request_irq failed with rc %d.\n", rc);
         }
         /* Force wakeup of the polling thread */
@@ -372,7 +386,6 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
 static void hvc_close(struct tty_struct *tty, struct file * filp)
 {
         struct hvc_struct *hp;
-        struct kobject *kobjp;
         int irq = 0;
         unsigned long flags;
 
@@ -382,7 +395,7 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
         /*
          * No driver_data means that this close was issued after a failed
          * hvc_open by the tty layer's release_dev() function and we can just
-         * exit cleanly because the kobject reference wasn't made.
+         * exit cleanly because the kref reference wasn't made.
          */
         if (!tty->driver_data)
                 return;
@@ -390,7 +403,6 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
         hp = tty->driver_data;
         spin_lock_irqsave(&hp->lock, flags);
 
-        kobjp = &hp->kobj;
         if (--hp->count == 0) {
                 if (hp->irq_requested)
                         irq = hp->irq;
@@ -417,7 +429,7 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
                 spin_unlock_irqrestore(&hp->lock, flags);
         }
 
-        kobject_put(kobjp);
+        kref_put(&hp->kref, destroy_hvc_struct);
 }
 
 static void hvc_hangup(struct tty_struct *tty)
@@ -426,7 +438,6 @@ static void hvc_hangup(struct tty_struct *tty)
         unsigned long flags;
         int irq = 0;
         int temp_open_count;
-        struct kobject *kobjp;
 
         if (!hp)
                 return;
@@ -443,7 +454,6 @@ static void hvc_hangup(struct tty_struct *tty)
                 return;
         }
 
-        kobjp = &hp->kobj;
         temp_open_count = hp->count;
         hp->count = 0;
         hp->n_outbuf = 0;
@@ -457,7 +467,7 @@ static void hvc_hangup(struct tty_struct *tty)
                 free_irq(irq, hp);
         while(temp_open_count) {
                 --temp_open_count;
-                kobject_put(kobjp);
+                kref_put(&hp->kref, destroy_hvc_struct);
         }
 }
 
@@ -729,27 +739,6 @@ static const struct tty_operations hvc_ops = {
         .chars_in_buffer = hvc_chars_in_buffer,
 };
 
-/* callback when the kboject ref count reaches zero. */
-static void destroy_hvc_struct(struct kobject *kobj)
-{
-        struct hvc_struct *hp = container_of(kobj, struct hvc_struct, kobj);
-        unsigned long flags;
-
-        spin_lock(&hvc_structs_lock);
-
-        spin_lock_irqsave(&hp->lock, flags);
-        list_del(&(hp->next));
-        spin_unlock_irqrestore(&hp->lock, flags);
-
-        spin_unlock(&hvc_structs_lock);
-
-        kfree(hp);
-}
-
-static struct kobj_type hvc_kobj_type = {
-        .release = destroy_hvc_struct,
-};
-
 struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq,
                                         struct hv_ops *ops, int outbuf_size)
 {
@@ -776,8 +765,7 @@ struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq,
         hp->outbuf_size = outbuf_size;
         hp->outbuf = &((char *)hp)[ALIGN(sizeof(*hp), sizeof(long))];
 
-        kobject_init(&hp->kobj);
-        hp->kobj.ktype = &hvc_kobj_type;
+        kref_init(&hp->kref);
 
         spin_lock_init(&hp->lock);
         spin_lock(&hvc_structs_lock);
@@ -806,12 +794,10 @@ struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq,
 int __devexit hvc_remove(struct hvc_struct *hp)
 {
         unsigned long flags;
-        struct kobject *kobjp;
         struct tty_struct *tty;
 
         spin_lock_irqsave(&hp->lock, flags);
         tty = hp->tty;
-        kobjp = &hp->kobj;
 
         if (hp->index < MAX_NR_HVC_CONSOLES)
                 vtermnos[hp->index] = -1;
@@ -821,12 +807,12 @@ int __devexit hvc_remove(struct hvc_struct *hp)
         spin_unlock_irqrestore(&hp->lock, flags);
 
         /*
-         * We 'put' the instance that was grabbed when the kobject instance
-         * was initialized using kobject_init().  Let the last holder of this
-         * kobject cause it to be removed, which will probably be the tty_hangup
+         * We 'put' the instance that was grabbed when the kref instance
+         * was initialized using kref_init().  Let the last holder of this
+         * kref cause it to be removed, which will probably be the tty_hangup
          * below.
          */
-        kobject_put(kobjp);
+        kref_put(&hp->kref, destroy_hvc_struct);
 
         /*
          * This function call will auto chain call hvc_hangup.  The tty should