[PATCH 3/3] TTY: con3215, use tty from tty_port

From: Jiri Slaby
Date: Wed Apr 11 2012 - 05:15:53 EST


Obtain tty_struct only once in ISR and pass it down to
raw3215_next_io. Other than that, we just use the tty with raised
reference. And set it properly in open and close.

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: linux390@xxxxxxxxxx
Cc: linux-s390@xxxxxxxxxxxxxxx
---
drivers/s390/char/con3215.c | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index f7bc23b..e928e04 100644
--- a/drivers/s390/char/con3215.c
+++ b/drivers/s390/char/con3215.c
@@ -83,7 +83,6 @@ struct raw3215_info {
int head; /* first free byte in output buffer */
int count; /* number of bytes in output buffer */
int written; /* number of bytes in write requests */
- struct tty_struct *tty; /* pointer to tty structure if present */
struct raw3215_req *queued_read; /* pointer to queued read requests */
struct raw3215_req *queued_write;/* pointer to queued write requests */
struct tasklet_struct tlet; /* tasklet to invoke tty_wakeup */
@@ -343,11 +342,11 @@ static void raw3215_wakeup(unsigned long data)
/*
* Try to start the next IO and wake up processes waiting on the tty.
*/
-static void raw3215_next_io(struct raw3215_info *raw)
+static void raw3215_next_io(struct raw3215_info *raw, struct tty_struct *tty)
{
raw3215_mk_write_req(raw);
raw3215_try_io(raw);
- if (raw->tty && RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE)
+ if (tty && RAW3215_BUFFER_SIZE - raw->count >= RAW3215_MIN_SPACE)
tasklet_schedule(&raw->tlet);
}

@@ -365,10 +364,11 @@ static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,

raw = dev_get_drvdata(&cdev->dev);
req = (struct raw3215_req *) intparm;
+ tty = tty_port_tty_get(&raw->port);
cstat = irb->scsw.cmd.cstat;
dstat = irb->scsw.cmd.dstat;
if (cstat != 0)
- raw3215_next_io(raw);
+ raw3215_next_io(raw, tty);
if (dstat & 0x01) { /* we got a unit exception */
dstat &= ~0x01; /* we can ignore it */
}
@@ -378,13 +378,13 @@ static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,
break;
/* Attention interrupt, someone hit the enter key */
raw3215_mk_read_req(raw);
- raw3215_next_io(raw);
+ raw3215_next_io(raw, tty);
break;
case 0x08:
case 0x0C:
/* Channel end interrupt. */
if ((raw = req->info) == NULL)
- return; /* That shouldn't happen ... */
+ goto put_tty; /* That shouldn't happen ... */
if (req->type == RAW3215_READ) {
/* store residual count, then wait for device end */
req->residual = irb->scsw.cmd.count;
@@ -394,11 +394,10 @@ static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,
case 0x04:
/* Device end interrupt. */
if ((raw = req->info) == NULL)
- return; /* That shouldn't happen ... */
- if (req->type == RAW3215_READ && raw->tty != NULL) {
+ goto put_tty; /* That shouldn't happen ... */
+ if (req->type == RAW3215_READ && tty != NULL) {
unsigned int cchar;

- tty = raw->tty;
count = 160 - req->residual;
EBCASC(raw->inbuf, count);
cchar = ctrlchar_handle(raw->inbuf, count, tty);
@@ -408,7 +407,7 @@ static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,

case CTRLCHAR_CTRL:
tty_insert_flip_char(tty, cchar, TTY_NORMAL);
- tty_flip_buffer_push(raw->tty);
+ tty_flip_buffer_push(tty);
break;

case CTRLCHAR_NONE:
@@ -421,7 +420,7 @@ static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,
} else
count -= 2;
tty_insert_flip_string(tty, raw->inbuf, count);
- tty_flip_buffer_push(raw->tty);
+ tty_flip_buffer_push(tty);
break;
}
} else if (req->type == RAW3215_WRITE) {
@@ -436,7 +435,7 @@ static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,
raw->queued_read == NULL) {
wake_up_interruptible(&raw->empty_wait);
}
- raw3215_next_io(raw);
+ raw3215_next_io(raw, tty);
break;
default:
/* Strange interrupt, I'll do my best to clean up */
@@ -448,9 +447,10 @@ static void raw3215_irq(struct ccw_device *cdev, unsigned long intparm,
raw->flags &= ~RAW3215_WORKING;
raw3215_free_req(req);
}
- raw3215_next_io(raw);
+ raw3215_next_io(raw, tty);
}
- return;
+put_tty:
+ tty_kref_put(tty);
}

/*
@@ -946,7 +946,7 @@ static int tty3215_open(struct tty_struct *tty, struct file * filp)
return -ENODEV;

tty->driver_data = raw;
- raw->tty = tty;
+ tty_port_tty_set(&raw->port, tty);

tty->low_latency = 0; /* don't use bottom half for pushing chars */
/*
@@ -977,7 +977,7 @@ static void tty3215_close(struct tty_struct *tty, struct file * filp)
raw3215_shutdown(raw);
tasklet_kill(&raw->tlet);
tty->closing = 0;
- raw->tty = NULL;
+ tty_port_tty_set(&raw->port, NULL);
}

/*
--
1.7.9.2


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