TTY: con3215, use tty from tty_port

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@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index f7bc23baf540bdaa83dcde525423199007f8f807..e928e04080017203f3806ab14176c7ea05ba10c2 100644 (file)
--- 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);
 }
 
 /*