TTY: switch tty_flip_buffer_push

Now, we start converting tty buffer functions to actually use
tty_port. This will allow us to get rid of the need of tty in many
call sites. Only tty_port will needed and hence no more
tty_port_tty_get in those paths.

Now, the one where most of tty_port_tty_get gets removed:
tty_flip_buffer_push.

IOW we also closed all the races in drivers not using tty_port_tty_get
at all yet.

Also we move tty_flip_buffer_push declaration from include/linux/tty.h
to include/linux/tty_flip.h to all others while we are changing it
anyway.

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

7 files changed, 23 insertions, 43 deletions

diff --git a/arch/ia64/hp/sim/simserial.c b/arch/ia64/hp/sim/simserial.c
index 942022a5bc86..da2f319fb71d 100644
--- a/arch/ia64/hp/sim/simserial.c
+++ b/arch/ia64/hp/sim/simserial.c
@@ -53,9 +53,8 @@ struct tty_driver *hp_simserial_driver;
 
 static struct console *console;
 
-static void receive_chars(struct tty_struct *tty)
+static void receive_chars(struct tty_port *port)
 {
-        struct tty_port *port = tty->port;
         unsigned char ch;
         static unsigned char seen_esc = 0;
 
@@ -85,7 +84,7 @@ static void receive_chars(struct tty_struct *tty)
                 if (tty_insert_flip_char(port, ch, TTY_NORMAL) == 0)
                         break;
         }
-        tty_flip_buffer_push(tty);
+        tty_flip_buffer_push(port);
 }
 
 /*
@@ -94,18 +93,9 @@ static void receive_chars(struct tty_struct *tty)
 static irqreturn_t rs_interrupt_single(int irq, void *dev_id)
 {
         struct serial_state *info = dev_id;
-        struct tty_struct *tty = tty_port_tty_get(&info->port);
 
-        if (!tty) {
-                printk(KERN_INFO "%s: tty=0 problem\n", __func__);
-                return IRQ_NONE;
-        }
-        /*
-         * pretty simple in our case, because we only get interrupts
-         * on inbound traffic
-         */
-        receive_chars(tty);
-        tty_kref_put(tty);
+        receive_chars(&info->port);
+
         return IRQ_HANDLED;
 }
 
diff --git a/arch/mn10300/kernel/mn10300-serial.c b/arch/mn10300/kernel/mn10300-serial.c
index ae61bd692b4b..1dd20dbfd098 100644
--- a/arch/mn10300/kernel/mn10300-serial.c
+++ b/arch/mn10300/kernel/mn10300-serial.c
@@ -525,7 +525,6 @@ static void mn10300_serial_receive_interrupt(struct mn10300_serial_port *port)
 {
         struct uart_icount *icount = &port->uart.icount;
         struct tty_port *port = &port->uart.state->port;
-        struct tty_struct *tty = port->tty;
         unsigned ix;
         int count;
         u8 st, ch, push, status, overrun;
@@ -538,7 +537,7 @@ static void mn10300_serial_receive_interrupt(struct mn10300_serial_port *port)
         count = tty_buffer_request_room(port, count);
         if (count == 0) {
                 if (!port->low_latency)
-                        tty_flip_buffer_push(tty);
+                        tty_flip_buffer_push(port);
                 return;
         }
 
@@ -547,7 +546,7 @@ try_again:
         ix = ACCESS_ONCE(port->rx_outp);
         if (CIRC_CNT(port->rx_inp, ix, MNSC_BUFFER_SIZE) == 0) {
                 if (push && !port->low_latency)
-                        tty_flip_buffer_push(tty);
+                        tty_flip_buffer_push(port);
                 return;
         }
 
@@ -679,7 +678,7 @@ insert:
         count--;
         if (count <= 0) {
                 if (!port->low_latency)
-                        tty_flip_buffer_push(tty);
+                        tty_flip_buffer_push(port);
                 return;
         }
 
diff --git a/arch/parisc/kernel/pdc_cons.c b/arch/parisc/kernel/pdc_cons.c
index 4d92a379eb21..d5cae55195ec 100644
--- a/arch/parisc/kernel/pdc_cons.c
+++ b/arch/parisc/kernel/pdc_cons.c
@@ -138,10 +138,6 @@ static const struct tty_operations pdc_console_tty_ops = {
 static void pdc_console_poll(unsigned long unused)
 {
         int data, count = 0;
-        struct tty_struct *tty = tty_port_tty_get(&tty_port);
-
-        if (!tty)
-                return;
 
         while (1) {
                 data = pdc_console_poll_key(NULL);
@@ -152,9 +148,7 @@ static void pdc_console_poll(unsigned long unused)
         }
 
         if (count)
-                tty_flip_buffer_push(tty);
-
-        tty_kref_put(tty);
+                tty_flip_buffer_push(&tty_port);
 
         if (pdc_cons.flags & CON_ENABLED)
                 mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
diff --git a/arch/um/drivers/chan.h b/arch/um/drivers/chan.h
index 02b5a76e98d9..78f1b8999964 100644
--- a/arch/um/drivers/chan.h
+++ b/arch/um/drivers/chan.h
@@ -27,8 +27,7 @@ struct chan {
         void *data;
 };
 
-extern void chan_interrupt(struct line *line,
-                           struct tty_struct *tty, int irq);
+extern void chan_interrupt(struct line *line, int irq);
 extern int parse_chan_pair(char *str, struct line *line, int device,
                            const struct chan_opts *opts, char **error_out);
 extern int write_chan(struct chan *chan, const char *buf, int len,
diff --git a/arch/um/drivers/chan_kern.c b/arch/um/drivers/chan_kern.c
index 795bd8102205..15c553c239a1 100644
--- a/arch/um/drivers/chan_kern.c
+++ b/arch/um/drivers/chan_kern.c
@@ -131,11 +131,9 @@ void chan_enable_winch(struct chan *chan, struct tty_struct *tty)
 static void line_timer_cb(struct work_struct *work)
 {
         struct line *line = container_of(work, struct line, task.work);
-        struct tty_struct *tty = tty_port_tty_get(&line->port);
 
         if (!line->throttled)
-                chan_interrupt(line, tty, line->driver->read_irq);
-        tty_kref_put(tty);
+                chan_interrupt(line, line->driver->read_irq);
 }
 
 int enable_chan(struct line *line)
@@ -546,7 +544,7 @@ int parse_chan_pair(char *str, struct line *line, int device,
         return 0;
 }
 
-void chan_interrupt(struct line *line, struct tty_struct *tty, int irq)
+void chan_interrupt(struct line *line, int irq)
 {
         struct tty_port *port = &line->port;
         struct chan *chan = line->chan_in;
@@ -570,8 +568,11 @@ void chan_interrupt(struct line *line, struct tty_struct *tty, int irq)
                 reactivate_fd(chan->fd, irq);
         if (err == -EIO) {
                 if (chan->primary) {
-                        if (tty != NULL)
+                        struct tty_struct *tty = tty_port_tty_get(&line->port);
+                        if (tty != NULL) {
                                 tty_hangup(tty);
+                                tty_kref_put(tty);
+                        }
                         if (line->chan_out != chan)
                                 close_one_chan(line->chan_out, 1);
                 }
@@ -580,6 +581,5 @@ void chan_interrupt(struct line *line, struct tty_struct *tty, int irq)
                         return;
         }
  out:
-        if (tty)
-                tty_flip_buffer_push(tty);
+        tty_flip_buffer_push(port);
 }
diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index 9ffc28bd4b7a..f1b38571f94e 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -19,11 +19,10 @@ static irqreturn_t line_interrupt(int irq, void *data)
 {
         struct chan *chan = data;
         struct line *line = chan->line;
-        struct tty_struct *tty = tty_port_tty_get(&line->port);
 
         if (line)
-                chan_interrupt(line, tty, irq);
-        tty_kref_put(tty);
+                chan_interrupt(line, irq);
+
         return IRQ_HANDLED;
 }
 
@@ -234,7 +233,7 @@ void line_unthrottle(struct tty_struct *tty)
         struct line *line = tty->driver_data;
 
         line->throttled = 0;
-        chan_interrupt(line, tty, line->driver->read_irq);
+        chan_interrupt(line, line->driver->read_irq);
 
         /*
          * Maybe there is enough stuff pending that calling the interrupt
diff --git a/arch/xtensa/platforms/iss/console.c b/arch/xtensa/platforms/iss/console.c
index 62447d63890c..da9866f7fecf 100644
--- a/arch/xtensa/platforms/iss/console.c
+++ b/arch/xtensa/platforms/iss/console.c
@@ -58,7 +58,8 @@ static int rs_open(struct tty_struct *tty, struct file * filp)
         tty->port = &serial_port;
         spin_lock(&timer_lock);
         if (tty->count == 1) {
-                setup_timer(&serial_timer, rs_poll, (unsigned long)tty);
+                setup_timer(&serial_timer, rs_poll,
+                                (unsigned long)&serial_port);
                 mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);
         }
         spin_unlock(&timer_lock);
@@ -97,9 +98,7 @@ static int rs_write(struct tty_struct * tty,
 
 static void rs_poll(unsigned long priv)
 {
-        struct tty_struct* tty = (struct tty_struct*) priv;
-        struct tty_port *port = tty->port;
-
+        struct tty_port *port = (struct tty_port *)priv;
         struct timeval tv = { .tv_sec = 0, .tv_usec = 0 };
         int i = 0;
         unsigned char c;
@@ -113,7 +112,7 @@ static void rs_poll(unsigned long priv)
         }
 
         if (i)
-                tty_flip_buffer_push(tty);
+                tty_flip_buffer_push(port);
 
 
         mod_timer(&serial_timer, jiffies + SERIAL_TIMER_VALUE);