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>

1 files changed, 16 insertions, 16 deletions

diff --git a/drivers/s390/char/con3215.c b/drivers/s390/char/con3215.c
index f7bc23baf540..e928e0408001 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);
 }
 
 /*