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Subject[PATCH 39/69] TTY: HVC, use count from tty_port
Date
Now, count is used from tty_port and protected by tty_port->lock.

n_outbuf is left unprotected in hvc_hangup now, because there is no
point to hold any lock, since other uses are unprotected too.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: linuxppc-dev@lists.ozlabs.org
---
drivers/tty/hvc/hvc_console.c | 40 +++++++++++++++++++++-------------------
drivers/tty/hvc/hvc_console.h | 1 -
2 files changed, 21 insertions(+), 20 deletions(-)

diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index 92b7f5d..6c45cbf 100644
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -313,18 +313,18 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
if (!(hp = hvc_get_by_index(tty->index)))
return -ENODEV;

- spin_lock_irqsave(&hp->lock, flags);
+ spin_lock_irqsave(&hp->port.lock, flags);
/* Check and then increment for fast path open. */
- if (hp->count++ > 0) {
+ if (hp->port.count++ > 0) {
+ spin_unlock_irqrestore(&hp->port.lock, flags);
+ /* FIXME why taking a reference here? */
tty_kref_get(tty);
- spin_unlock_irqrestore(&hp->lock, flags);
hvc_kick();
return 0;
} /* else count == 0 */
+ spin_unlock_irqrestore(&hp->port.lock, flags);

tty->driver_data = hp;
- spin_unlock_irqrestore(&hp->lock, flags);
-
tty_port_tty_set(&hp->port, tty);

if (hp->ops->notifier_add)
@@ -367,10 +367,10 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)

hp = tty->driver_data;

- spin_lock_irqsave(&hp->lock, flags);
+ spin_lock_irqsave(&hp->port.lock, flags);

- if (--hp->count == 0) {
- spin_unlock_irqrestore(&hp->lock, flags);
+ if (--hp->port.count == 0) {
+ spin_unlock_irqrestore(&hp->port.lock, flags);
/* We are done with the tty pointer now. */
tty_port_tty_set(&hp->port, NULL);

@@ -387,10 +387,10 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
*/
tty_wait_until_sent_from_close(tty, HVC_CLOSE_WAIT);
} else {
- if (hp->count < 0)
+ if (hp->port.count < 0)
printk(KERN_ERR "hvc_close %X: oops, count is %d\n",
- hp->vtermno, hp->count);
- spin_unlock_irqrestore(&hp->lock, flags);
+ hp->vtermno, hp->port.count);
+ spin_unlock_irqrestore(&hp->port.lock, flags);
}

tty_kref_put(tty);
@@ -409,24 +409,25 @@ static void hvc_hangup(struct tty_struct *tty)
/* cancel pending tty resize work */
cancel_work_sync(&hp->tty_resize);

- spin_lock_irqsave(&hp->lock, flags);
+ spin_lock_irqsave(&hp->port.lock, flags);

/*
* The N_TTY line discipline has problems such that in a close vs
* open->hangup case this can be called after the final close so prevent
* that from happening for now.
*/
- if (hp->count <= 0) {
- spin_unlock_irqrestore(&hp->lock, flags);
+ if (hp->port.count <= 0) {
+ spin_unlock_irqrestore(&hp->port.lock, flags);
return;
}

- temp_open_count = hp->count;
- hp->count = 0;
- hp->n_outbuf = 0;
- spin_unlock_irqrestore(&hp->lock, flags);
+ temp_open_count = hp->port.count;
+ hp->port.count = 0;
+ spin_unlock_irqrestore(&hp->port.lock, flags);
tty_port_tty_set(&hp->port, NULL);

+ hp->n_outbuf = 0;
+
if (hp->ops->notifier_hangup)
hp->ops->notifier_hangup(hp, hp->data);

@@ -474,7 +475,8 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count
if (!hp)
return -EPIPE;

- if (hp->count <= 0)
+ /* FIXME what's this (unprotected) check for? */
+ if (hp->port.count <= 0)
return -EIO;

spin_lock_irqsave(&hp->lock, flags);
diff --git a/drivers/tty/hvc/hvc_console.h b/drivers/tty/hvc/hvc_console.h
index 594a28f..674d23c 100644
--- a/drivers/tty/hvc/hvc_console.h
+++ b/drivers/tty/hvc/hvc_console.h
@@ -49,7 +49,6 @@ struct hvc_struct {
struct tty_port port;
spinlock_t lock;
int index;
- int count;
int do_wakeup;
char *outbuf;
int outbuf_size;
--
1.7.9.2



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