TTY: hvsi, use tty from tty_port

Now, we switch to the refcounted model and do not need hp->lock to
protect hp->tty anymore.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 21 insertions, 14 deletions

diff --git a/drivers/tty/hvc/hvsi.c b/drivers/tty/hvc/hvsi.c
index 68b729b8d1eb..6f5bc49c441f 100644
--- a/drivers/tty/hvc/hvsi.c
+++ b/drivers/tty/hvc/hvsi.c
@@ -76,7 +76,6 @@ struct hvsi_struct {
         wait_queue_head_t stateq; /* woken when HVSI state changes */
         spinlock_t lock;
         int index;
-        struct tty_struct *tty;
         uint8_t throttle_buf[128];
         uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
         /* inbuf is for packet reassembly. leave a little room for leftovers. */
@@ -492,14 +491,17 @@ static irqreturn_t hvsi_interrupt(int irq, void *arg)
 {
         struct hvsi_struct *hp = (struct hvsi_struct *)arg;
         struct hvsi_struct *handshake;
+        struct tty_struct *tty;
         unsigned long flags;
         int again = 1;
 
         pr_debug("%s\n", __func__);
 
+        tty = tty_port_tty_get(&hp->port);
+
         while (again) {
                 spin_lock_irqsave(&hp->lock, flags);
-                again = hvsi_load_chunk(hp, hp->tty, &handshake);
+                again = hvsi_load_chunk(hp, tty, &handshake);
                 spin_unlock_irqrestore(&hp->lock, flags);
 
                 if (handshake) {
@@ -509,15 +511,16 @@ static irqreturn_t hvsi_interrupt(int irq, void *arg)
         }
 
         spin_lock_irqsave(&hp->lock, flags);
-        if (hp->tty && hp->n_throttle
-                        && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) {
-                /* we weren't hung up and we weren't throttled, so we can deliver the
-                 * rest now */
-                hvsi_send_overflow(hp, hp->tty);
-                tty_flip_buffer_push(hp->tty);
+        if (tty && hp->n_throttle && !test_bit(TTY_THROTTLED, &tty->flags)) {
+                /* we weren't hung up and we weren't throttled, so we can
+                 * deliver the rest now */
+                hvsi_send_overflow(hp, tty);
+                tty_flip_buffer_push(tty);
         }
         spin_unlock_irqrestore(&hp->lock, flags);
 
+        tty_kref_put(tty);
+
         return IRQ_HANDLED;
 }
 
@@ -724,8 +727,8 @@ static int hvsi_open(struct tty_struct *tty, struct file *filp)
         if (hp->state == HVSI_FSP_DIED)
                 return -EIO;
 
+        tty_port_tty_set(&hp->port, tty);
         spin_lock_irqsave(&hp->lock, flags);
-        hp->tty = tty;
         hp->port.count++;
         atomic_set(&hp->seqno, 0);
         h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE);
@@ -784,7 +787,7 @@ static void hvsi_close(struct tty_struct *tty, struct file *filp)
         spin_lock_irqsave(&hp->lock, flags);
 
         if (--hp->port.count == 0) {
-                hp->tty = NULL;
+                tty_port_tty_set(&hp->port, NULL);
                 hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */
 
                 /* only close down connection if it is not the console */
@@ -830,12 +833,11 @@ static void hvsi_hangup(struct tty_struct *tty)
 
         pr_debug("%s\n", __func__);
 
-        spin_lock_irqsave(&hp->lock, flags);
+        tty_port_tty_set(&hp->port, NULL);
 
+        spin_lock_irqsave(&hp->lock, flags);
         hp->port.count = 0;
         hp->n_outbuf = 0;
-        hp->tty = NULL;
-
         spin_unlock_irqrestore(&hp->lock, flags);
 }
 
@@ -863,6 +865,7 @@ static void hvsi_write_worker(struct work_struct *work)
 {
         struct hvsi_struct *hp =
                 container_of(work, struct hvsi_struct, writer.work);
+        struct tty_struct *tty;
         unsigned long flags;
 #ifdef DEBUG
         static long start_j = 0;
@@ -896,7 +899,11 @@ static void hvsi_write_worker(struct work_struct *work)
                 start_j = 0;
 #endif /* DEBUG */
                 wake_up_all(&hp->emptyq);
-                tty_wakeup(hp->tty);
+                tty = tty_port_tty_get(&hp->port);
+                if (tty) {
+                        tty_wakeup(tty);
+                        tty_kref_put(tty);
+                }
         }
 
 out: