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>

1 files changed, 14 insertions, 16 deletions

diff --git a/drivers/tty/serial/pmac_zilog.c b/drivers/tty/serial/pmac_zilog.c
index 73a3f295e7c4..b1785f58b6e3 100644
--- a/drivers/tty/serial/pmac_zilog.c
+++ b/drivers/tty/serial/pmac_zilog.c
@@ -227,21 +227,19 @@ static void pmz_interrupt_control(struct uart_pmac_port *uap, int enable)
         write_zsreg(uap, R1, uap->curregs[1]);
 }
 
-static struct tty_struct *pmz_receive_chars(struct uart_pmac_port *uap)
+static bool pmz_receive_chars(struct uart_pmac_port *uap)
 {
         struct tty_port *port;
-        struct tty_struct *tty = NULL;
         unsigned char ch, r1, drop, error, flag;
         int loops = 0;
 
         /* Sanity check, make sure the old bug is no longer happening */
-        if (uap->port.state == NULL || uap->port.state->port.tty == NULL) {
+        if (uap->port.state == NULL) {
                 WARN_ON(1);
                 (void)read_zsdata(uap);
-                return NULL;
+                return false;
         }
         port = &uap->port.state->port;
-        tty = port->tty; /* TOCTOU above */
 
         while (1) {
                 error = 0;
@@ -330,11 +328,11 @@ static struct tty_struct *pmz_receive_chars(struct uart_pmac_port *uap)
                         break;
         }
 
-        return tty;
+        return true;
  flood:
         pmz_interrupt_control(uap, 0);
         pmz_error("pmz: rx irq flood !\n");
-        return tty;
+        return true;
 }
 
 static void pmz_status_handle(struct uart_pmac_port *uap)
@@ -455,7 +453,7 @@ static irqreturn_t pmz_interrupt(int irq, void *dev_id)
         struct uart_pmac_port *uap_a;
         struct uart_pmac_port *uap_b;
         int rc = IRQ_NONE;
-        struct tty_struct *tty;
+        bool push;
         u8 r3;
 
         uap_a = pmz_get_port_A(uap);
@@ -468,7 +466,7 @@ static irqreturn_t pmz_interrupt(int irq, void *dev_id)
         pmz_debug("irq, r3: %x\n", r3);
 #endif
         /* Channel A */
-        tty = NULL;
+        push = false;
         if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
                 if (!ZS_IS_OPEN(uap_a)) {
                         pmz_debug("ChanA interrupt while not open !\n");
@@ -479,21 +477,21 @@ static irqreturn_t pmz_interrupt(int irq, void *dev_id)
                 if (r3 & CHAEXT)
                         pmz_status_handle(uap_a);
                 if (r3 & CHARxIP)
-                        tty = pmz_receive_chars(uap_a);
+                        push = pmz_receive_chars(uap_a);
                 if (r3 & CHATxIP)
                         pmz_transmit_chars(uap_a);
                 rc = IRQ_HANDLED;
         }
  skip_a:
         spin_unlock(&uap_a->port.lock);
-        if (tty != NULL)
-                tty_flip_buffer_push(tty);
+        if (push)
+                tty_flip_buffer_push(&uap->port.state->port);
 
         if (!uap_b)
                 goto out;
 
         spin_lock(&uap_b->port.lock);
-        tty = NULL;
+        push = false;
         if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
                 if (!ZS_IS_OPEN(uap_b)) {
                         pmz_debug("ChanB interrupt while not open !\n");
@@ -504,15 +502,15 @@ static irqreturn_t pmz_interrupt(int irq, void *dev_id)
                 if (r3 & CHBEXT)
                         pmz_status_handle(uap_b);
                 if (r3 & CHBRxIP)
-                        tty = pmz_receive_chars(uap_b);
+                        push = pmz_receive_chars(uap_b);
                 if (r3 & CHBTxIP)
                         pmz_transmit_chars(uap_b);
                 rc = IRQ_HANDLED;
         }
  skip_b:
         spin_unlock(&uap_b->port.lock);
-        if (tty != NULL)
-                tty_flip_buffer_push(tty);
+        if (push)
+                tty_flip_buffer_push(&uap->port.state->port);
 
  out:
         return rc;