[PATCH 034/196] kobject: convert hvc_console to use kref, not kobject

Greg Kroah-Hartman
2008-01-25T07:25:47Z

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>
---
drivers/char/hvc_console.c | 80 ++++++++++++++++++--------------------------
1 files changed, 33 insertions(+), 47 deletions(-)

diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index 8252f86..480fae2 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
--
1.5.3.8