patch-2.4.1 linux/drivers/char/n_tty.c

• Lines: 82
• Date: Mon Jan 15 18:58:04 2001
• Orig file: v2.4.0/linux/drivers/char/n_tty.c
• Orig date: Mon Jul 31 10:14:07 2000

diff -u --recursive --new-file v2.4.0/linux/drivers/char/n_tty.c linux/drivers/char/n_tty.c
@@ -86,6 +86,15 @@
 		free_page((unsigned long) buf);
 }
 
+static inline void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
+{
+	if (tty->read_cnt < N_TTY_BUF_SIZE) {
+		tty->read_buf[tty->read_head] = c;
+		tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1);
+		tty->read_cnt++;
+	}
+}
+
 static inline void put_tty_queue(unsigned char c, struct tty_struct *tty)
 {
 	unsigned long flags;
@@ -94,11 +103,7 @@
 	 *	Why didn't anyone see this one comming? --AJK
 	*/
 	spin_lock_irqsave(&tty->read_lock, flags);
-	if (tty->read_cnt < N_TTY_BUF_SIZE) {
-		tty->read_buf[tty->read_head] = c;
-		tty->read_head = (tty->read_head + 1) & (N_TTY_BUF_SIZE-1);
-		tty->read_cnt++;
-	}
+	put_tty_queue_nolock(c, tty);
 	spin_unlock_irqrestore(&tty->read_lock, flags);
 }
 
@@ -499,6 +504,8 @@
 
 static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
 {
+	unsigned long flags;
+
 	if (tty->raw) {
 		put_tty_queue(c, tty);
 		return;
@@ -651,10 +658,12 @@
 				put_tty_queue(c, tty);
 
 		handle_newline:
+			spin_lock_irqsave(&tty->read_lock, flags);
 			set_bit(tty->read_head, &tty->read_flags);
-			put_tty_queue(c, tty);
+			put_tty_queue_nolock(c, tty);
 			tty->canon_head = tty->read_head;
 			tty->canon_data++;
+			spin_unlock_irqrestore(&tty->read_lock, flags);
 			kill_fasync(&tty->fasync, SIGIO, POLL_IN);
 			if (waitqueue_active(&tty->read_wait))
 				wake_up_interruptible(&tty->read_wait);
@@ -1055,12 +1064,6 @@
 				tty->read_tail = ((tty->read_tail+1) &
 						  (N_TTY_BUF_SIZE-1));
 				tty->read_cnt--;
-				spin_unlock_irqrestore(&tty->read_lock, flags);
-
-				if (!eol || (c != __DISABLED_CHAR)) {
-					put_user(c, b++);
-					nr--;
-				}
 				if (eol) {
 					/* this test should be redundant:
 					 * we shouldn't be reading data if
@@ -1068,8 +1071,15 @@
 					 */
 					if (--tty->canon_data < 0)
 						tty->canon_data = 0;
-					break;
 				}
+				spin_unlock_irqrestore(&tty->read_lock, flags);
+
+				if (!eol || (c != __DISABLED_CHAR)) {
+					put_user(c, b++);
+					nr--;
+				}
+				if (eol)
+					break;
 			}
 		} else {
 			int uncopied;