TTY: remove unneeded tty->index checks

Checking if tty->index is in bounds is not needed. The tty has the
index set in the initial open. This is done in get_tty_driver. And it
can be only in interval <0,driver->num).

So remove the tests which check exactly this interval. Some are
left untouched as they check against the current backing device count.
(Leaving apart that the check is racy in most of the cases.)

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

12 files changed, 26 insertions, 59 deletions

diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c
index b42f00d987a..75328625755 100644
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -1768,13 +1768,9 @@ static int get_async_struct(int line, struct async_struct **ret_info)
 static int rs_open(struct tty_struct *tty, struct file * filp)
 {
 	struct async_struct	*info;
-	int 			retval, line;
+	int retval;
 
-	line = tty->index;
-	if ((line < 0) || (line >= NR_PORTS)) {
-		return -ENODEV;
-	}
-	retval = get_async_struct(line, &info);
+	retval = get_async_struct(tty->index, &info);
 	if (retval) {
 		return retval;
 	}
@@ -1964,7 +1960,7 @@ static int __init amiga_serial_probe(struct platform_device *pdev)
 	struct serial_state * state;
 	int error;
 
-	serial_driver = alloc_tty_driver(1);
+	serial_driver = alloc_tty_driver(NR_PORTS);
 	if (!serial_driver)
 		return -ENOMEM;
 
diff --git a/drivers/tty/cyclades.c b/drivers/tty/cyclades.c
index bc7b5a5650b..e61cabdd69d 100644
--- a/drivers/tty/cyclades.c
+++ b/drivers/tty/cyclades.c
@@ -1515,13 +1515,9 @@ static void cy_shutdown(struct cyclades_port *info, struct tty_struct *tty)
 static int cy_open(struct tty_struct *tty, struct file *filp)
 {
 	struct cyclades_port *info;
-	unsigned int i, line;
+	unsigned int i, line = tty->index;
 	int retval;
 
-	line = tty->index;
-	if (tty->index < 0 || NR_PORTS <= line)
-		return -ENODEV;
-
 	for (i = 0; i < NR_CARDS; i++)
 		if (line < cy_card[i].first_line + cy_card[i].nports &&
 				line >= cy_card[i].first_line)
diff --git a/drivers/tty/hvc/hvcs.c b/drivers/tty/hvc/hvcs.c
index da0aa476804..d23759183b4 100644
--- a/drivers/tty/hvc/hvcs.c
+++ b/drivers/tty/hvc/hvcs.c
@@ -1090,27 +1090,23 @@ static int hvcs_enable_device(struct hvcs_struct *hvcsd, uint32_t unit_address,
  */
 static struct hvcs_struct *hvcs_get_by_index(int index)
 {
-	struct hvcs_struct *hvcsd = NULL;
+	struct hvcs_struct *hvcsd;
 	unsigned long flags;
 
 	spin_lock(&hvcs_structs_lock);
-	/* We can immediately discard OOB requests */
-	if (index >= 0 && index < HVCS_MAX_SERVER_ADAPTERS) {
-		list_for_each_entry(hvcsd, &hvcs_structs, next) {
-			spin_lock_irqsave(&hvcsd->lock, flags);
-			if (hvcsd->index == index) {
-				kref_get(&hvcsd->kref);
-				spin_unlock_irqrestore(&hvcsd->lock, flags);
-				spin_unlock(&hvcs_structs_lock);
-				return hvcsd;
-			}
+	list_for_each_entry(hvcsd, &hvcs_structs, next) {
+		spin_lock_irqsave(&hvcsd->lock, flags);
+		if (hvcsd->index == index) {
+			kref_get(&hvcsd->kref);
 			spin_unlock_irqrestore(&hvcsd->lock, flags);
+			spin_unlock(&hvcs_structs_lock);
+			return hvcsd;
 		}
-		hvcsd = NULL;
+		spin_unlock_irqrestore(&hvcsd->lock, flags);
 	}
-
 	spin_unlock(&hvcs_structs_lock);
-	return hvcsd;
+
+	return NULL;
 }
 
 /*
diff --git a/drivers/tty/hvc/hvsi.c b/drivers/tty/hvc/hvsi.c
index 60bc4516418..a7488b74864 100644
--- a/drivers/tty/hvc/hvsi.c
+++ b/drivers/tty/hvc/hvsi.c
@@ -737,14 +737,11 @@ static int hvsi_open(struct tty_struct *tty, struct file *filp)
 {
 	struct hvsi_struct *hp;
 	unsigned long flags;
-	int line = tty->index;
 	int ret;
 
 	pr_debug("%s\n", __func__);
 
-	if (line < 0 || line >= hvsi_count)
-		return -ENODEV;
-	hp = &hvsi_ports[line];
+	hp = &hvsi_ports[tty->index];
 
 	tty->driver_data = hp;
 
diff --git a/drivers/tty/isicom.c b/drivers/tty/isicom.c
index b3a28b5f02a..03c14979acc 100644
--- a/drivers/tty/isicom.c
+++ b/drivers/tty/isicom.c
@@ -849,8 +849,6 @@ static struct tty_port *isicom_find_port(struct tty_struct *tty)
 	unsigned int board;
 	int line = tty->index;
 
-	if (line < 0 || line > PORT_COUNT-1)
-		return NULL;
 	board = BOARD(line);
 	card = &isi_card[board];
 
diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 260d0312352..17ff377e412 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -1010,8 +1010,6 @@ static int mxser_open(struct tty_struct *tty, struct file *filp)
 	line = tty->index;
 	if (line == MXSER_PORTS)
 		return 0;
-	if (line < 0 || line > MXSER_PORTS)
-		return -ENODEV;
 	info = &mxser_boards[line / MXSER_PORTS_PER_BOARD].ports[line % MXSER_PORTS_PER_BOARD];
 	if (!info->ioaddr)
 		return -ENODEV;
diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c
index b088e1ea433..777d5f9cf6c 100644
--- a/drivers/tty/rocket.c
+++ b/drivers/tty/rocket.c
@@ -892,12 +892,12 @@ static int rp_open(struct tty_struct *tty, struct file *filp)
 {
 	struct r_port *info;
 	struct tty_port *port;
-	int line = 0, retval;
+	int retval;
 	CHANNEL_t *cp;
 	unsigned long page;
 
-	line = tty->index;
-	if (line < 0 || line >= MAX_RP_PORTS || ((info = rp_table[line]) == NULL))
+	info = rp_table[tty->index];
+	if (info == NULL)
 		return -ENXIO;
 	port = &info->port;
 	
diff --git a/drivers/tty/serial/68328serial.c b/drivers/tty/serial/68328serial.c
index a88ef9782a4..7398390e7e6 100644
--- a/drivers/tty/serial/68328serial.c
+++ b/drivers/tty/serial/68328serial.c
@@ -1190,14 +1190,9 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
 int rs_open(struct tty_struct *tty, struct file * filp)
 {
 	struct m68k_serial	*info;
-	int 			retval, line;
-
-	line = tty->index;
-	
-	if (line >= NR_PORTS || line < 0) /* we have exactly one */
-		return -ENODEV;
+	int retval;
 
-	info = &m68k_soft[line];
+	info = &m68k_soft[tty->index];
 
 	if (serial_paranoia_check(info, tty->name, "rs_open"))
 		return -ENODEV;
diff --git a/drivers/tty/serial/crisv10.c b/drivers/tty/serial/crisv10.c
index 1dfba7b779c..23d79169687 100644
--- a/drivers/tty/serial/crisv10.c
+++ b/drivers/tty/serial/crisv10.c
@@ -4105,20 +4105,11 @@ static int
 rs_open(struct tty_struct *tty, struct file * filp)
 {
 	struct e100_serial	*info;
-	int 			retval, line;
+	int 			retval;
 	unsigned long           page;
 	int                     allocated_resources = 0;
 
-	/* find which port we want to open */
-	line = tty->index;
-
-	if (line < 0 || line >= NR_PORTS)
-		return -ENODEV;
-
-	/* find the corresponding e100_serial struct in the table */
-	info = rs_table + line;
-
-	/* don't allow the opening of ports that are not enabled in the HW config */
+	info = rs_table + tty->index;
 	if (!info->enabled)
 		return -ENODEV;
 
@@ -4131,7 +4122,7 @@ rs_open(struct tty_struct *tty, struct file * filp)
 	tty->driver_data = info;
 	info->port.tty = tty;
 
-	info->port.tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
+	tty->low_latency = !!(info->flags & ASYNC_LOW_LATENCY);
 
 	if (!tmp_buf) {
 		page = get_zeroed_page(GFP_KERNEL);
diff --git a/drivers/tty/synclink.c b/drivers/tty/synclink.c
index 2b2988c779c..8e518da85fd 100644
--- a/drivers/tty/synclink.c
+++ b/drivers/tty/synclink.c
@@ -3381,7 +3381,7 @@ static int mgsl_open(struct tty_struct *tty, struct file * filp)
 
 	/* verify range of specified line number */	
 	line = tty->index;
-	if ((line < 0) || (line >= mgsl_device_count)) {
+	if (line >= mgsl_device_count) {
 		printk("%s(%d):mgsl_open with invalid line #%d.\n",
 			__FILE__,__LINE__,line);
 		return -ENODEV;
diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c
index a8b66be37e6..6bee4907c6a 100644
--- a/drivers/tty/synclink_gt.c
+++ b/drivers/tty/synclink_gt.c
@@ -654,7 +654,7 @@ static int open(struct tty_struct *tty, struct file *filp)
 	unsigned long flags;
 
 	line = tty->index;
-	if ((line < 0) || (line >= slgt_device_count)) {
+	if (line >= slgt_device_count) {
 		DBGERR(("%s: open with invalid line #%d.\n", driver_name, line));
 		return -ENODEV;
 	}
diff --git a/drivers/tty/synclinkmp.c b/drivers/tty/synclinkmp.c
index ddabb61c85b..4fb6c4b31b7 100644
--- a/drivers/tty/synclinkmp.c
+++ b/drivers/tty/synclinkmp.c
@@ -721,7 +721,7 @@ static int open(struct tty_struct *tty, struct file *filp)
 	unsigned long flags;
 
 	line = tty->index;
-	if ((line < 0) || (line >= synclinkmp_device_count)) {
+	if (line >= synclinkmp_device_count) {
 		printk("%s(%d): open with invalid line #%d.\n",
 			__FILE__,__LINE__,line);
 		return -ENODEV;