tty: release BTM while sleeping in block_til_ready

Most tty drivers may block while opening a device.
Since this possibly depends on another thread
closing it first and both threads may need the BTM,
we need to release it here.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/char/amiserial.c

@@ -1710,7 +1710,9 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
 		printk("block_til_ready blocking: ttys%d, count = %d\n",
 		       info->line, state->count);
 #endif
+		tty_unlock();
 		schedule();
+		tty_lock();
 	}
 	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(&info->open_wait, &wait);

drivers/char/ip2/ip2main.c

@@ -1486,7 +1486,9 @@ ip2_open( PTTY tty, struct file *pFile )
 
 	if ( tty_hung_up_p(pFile) || ( pCh->flags & ASYNC_CLOSING )) {
 		if ( pCh->flags & ASYNC_CLOSING ) {
+			tty_unlock();
 			schedule();
+			tty_lock();
 		}
 		if ( tty_hung_up_p(pFile) ) {
 			set_current_state( TASK_RUNNING );
@@ -1548,7 +1550,9 @@ ip2_open( PTTY tty, struct file *pFile )
 			rc = (( pCh->flags & ASYNC_HUP_NOTIFY ) ? -EAGAIN : -ERESTARTSYS);
 			break;
 		}
+		tty_unlock();
 		schedule();
+		tty_lock();
 	}
 	set_current_state( TASK_RUNNING );
 	remove_wait_queue(&pCh->open_wait, &wait);

drivers/char/serial167.c

@@ -1786,7 +1786,9 @@ block_til_ready(struct tty_struct *tty, struct file *filp,
 		       tty->name, info->count);
 		/**/
 #endif
-		    schedule();
+		tty_unlock();
+		schedule();
+		tty_lock();
 	}
 	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(&info->open_wait, &wait);

drivers/char/specialix.c

@@ -1365,7 +1365,9 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
 			retval = -ERESTARTSYS;
 			break;
 		}
+		tty_unlock();
 		schedule();
+		tty_lock();
 	}
 
 	set_current_state(TASK_RUNNING);

drivers/char/synclink.c

@@ -3349,7 +3349,9 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
 			printk("%s(%d):block_til_ready blocking on %s count=%d\n",
 				 __FILE__,__LINE__, tty->driver->name, port->count );
 
+		tty_unlock();
 		schedule();
+		tty_lock();
 	}
 
 	set_current_state(TASK_RUNNING);

drivers/char/synclink_gt.c

@@ -3244,7 +3244,9 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
 		}
 
 		DBGINFO(("%s block_til_ready wait\n", tty->driver->name));
+		tty_unlock();
 		schedule();
+		tty_lock();
 	}
 
 	set_current_state(TASK_RUNNING);

drivers/char/synclinkmp.c

@@ -3365,7 +3365,9 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
 			printk("%s(%d):%s block_til_ready() count=%d\n",
 				 __FILE__,__LINE__, tty->driver->name, port->count );
 
+		tty_unlock();
 		schedule();
+		tty_lock();
 	}
 
 	set_current_state(TASK_RUNNING);

drivers/char/tty_port.c

@@ -294,7 +294,9 @@ int tty_port_block_til_ready(struct tty_port *port,
 			retval = -ERESTARTSYS;
 			break;
 		}
+		tty_unlock();
 		schedule();
+		tty_lock();
 	}
 	finish_wait(&port->open_wait, &wait);
 

drivers/serial/68328serial.c

@@ -1235,7 +1235,9 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
 			retval = -ERESTARTSYS;
 			break;
 		}
+		tty_unlock();
 		schedule();
+		tty_lock();
 	}
 	current->state = TASK_RUNNING;
 	remove_wait_queue(&info->open_wait, &wait);

drivers/serial/68360serial.c

@@ -1860,7 +1860,9 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
 		printk("block_til_ready blocking: ttys%d, count = %d\n",
 		       info->line, state->count);
 #endif
+		tty_unlock();
 		schedule();
+		tty_lock();
 	}
 	current->state = TASK_RUNNING;
 	remove_wait_queue(&info->open_wait, &wait);

drivers/serial/crisv10.c

@@ -4066,7 +4066,9 @@ block_til_ready(struct tty_struct *tty, struct file * filp,
 		printk("block_til_ready blocking: ttyS%d, count = %d\n",
 		       info->line, info->count);
 #endif
+		tty_unlock();
 		schedule();
+		tty_lock();
 	}
 	set_current_state(TASK_RUNNING);
 	remove_wait_queue(&info->open_wait, &wait);