n_hdlc: remove cached tty

It's not needed, as now it's clear, that it's always the same as the one
passed from the tty layer.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219084118.26491-13-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
index 39a58fe..2ac7029 100644 (file)
--- a/drivers/tty/n_hdlc.c
+++ b/drivers/tty/n_hdlc.c
@@ -124,7 +124,6 @@ struct n_hdlc_buf_list {
 /**
  * struct n_hdlc - per device instance data structure
  * @magic - magic value for structure
- * @tty - ptr to TTY structure
  * @tbusy - reentrancy flag for tx wakeup code
  * @woke_up - FIXME: describe this field
  * @tx_buf_list - list of pending transmit frame buffers
@@ -134,7 +133,6 @@ struct n_hdlc_buf_list {
  */
 struct n_hdlc {
        int                     magic;
-       struct tty_struct       *tty;
        int                     tbusy;
        int                     woke_up;
        struct n_hdlc_buf_list  tx_buf_list;
@@ -240,8 +238,6 @@ static void n_hdlc_tty_close(struct tty_struct *tty)
        clear_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
 #endif
        tty->disc_data = NULL;
-       if (tty != n_hdlc->tty)
-               return;
 
        /* Ensure that the n_hdlcd process is not hanging on select()/poll() */
        wake_up_interruptible(&tty->read_wait);
@@ -280,7 +276,6 @@ static int n_hdlc_tty_open (struct tty_struct *tty)
        }
                
        tty->disc_data = n_hdlc;
-       n_hdlc->tty    = tty;
        tty->receive_room = 65536;
        
 #if defined(TTY_NO_WRITE_SPLIT)
@@ -391,11 +386,6 @@ static void n_hdlc_tty_wakeup(struct tty_struct *tty)
        if (!n_hdlc)
                return;
 
-       if (tty != n_hdlc->tty) {
-               clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
-               return;
-       }
-
        n_hdlc_send_frames (n_hdlc, tty);
                
 }      /* end of n_hdlc_tty_wakeup() */
@@ -420,7 +410,7 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,
                        __FILE__, __LINE__, __func__, count);
 
        /* This can happen if stuff comes in on the backup tty */
-       if (!n_hdlc || tty != n_hdlc->tty)
+       if (!n_hdlc)
                return;
                
        /* verify line is using HDLC discipline */
@@ -461,8 +451,8 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data,
        
        /* wake up any blocked reads and perform async signalling */
        wake_up_interruptible (&tty->read_wait);
-       if (n_hdlc->tty->fasync != NULL)
-               kill_fasync (&n_hdlc->tty->fasync, SIGIO, POLL_IN);
+       if (tty->fasync != NULL)
+               kill_fasync(&tty->fasync, SIGIO, POLL_IN);
 
 }      /* end of n_hdlc_tty_receive() */
 
@@ -598,8 +588,7 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
                schedule();
                        
                n_hdlc = tty->disc_data;
-               if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC || 
-                   tty != n_hdlc->tty) {
+               if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC) {
                        printk("n_hdlc_tty_write: %p invalid after wait!\n", n_hdlc);
                        error = -EIO;
                        break;
@@ -712,7 +701,7 @@ static __poll_t n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
        struct n_hdlc *n_hdlc = tty->disc_data;
        __poll_t mask = 0;
 
-       if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC || tty != n_hdlc->tty)
+       if (!n_hdlc || n_hdlc->magic != HDLC_MAGIC)
                return 0;
 
        /*