serial: icom: move array overflow checks earlier

This code does an annoying thing where it writes to the array and then
checks later for array overflows.  I don't know if it's actually
possible to overflow but let's check before using the array index.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/icom.c b/drivers/tty/serial/icom.c
index 7c9a06732ae5ee74b324360a25ec1f9bf76bd320..d98e4334897040cd7e6a482fee5a7a913338c4ec 100644 (file)
--- a/drivers/tty/serial/icom.c
+++ b/drivers/tty/serial/icom.c
@@ -297,25 +297,25 @@ static void stop_processor(struct icom_port *icom_port)
        spin_lock_irqsave(&icom_lock, flags);
 
        port = icom_port->port;
+       if (port >= ARRAY_SIZE(stop_proc)) {
+               dev_err(&icom_port->adapter->pci_dev->dev,
+                       "Invalid port assignment\n");
+               goto unlock;
+       }
+
        if (port == 0 || port == 1)
                stop_proc[port].global_control_reg = &icom_port->global_reg->control;
        else
                stop_proc[port].global_control_reg = &icom_port->global_reg->control_2;
 
+       temp = readl(stop_proc[port].global_control_reg);
+       temp = (temp & ~start_proc[port].processor_id) | stop_proc[port].processor_id;
+       writel(temp, stop_proc[port].global_control_reg);
 
-       if (port < 4) {
-               temp = readl(stop_proc[port].global_control_reg);
-               temp =
-                       (temp & ~start_proc[port].processor_id) | stop_proc[port].processor_id;
-               writel(temp, stop_proc[port].global_control_reg);
-
-               /* write flush */
-               readl(stop_proc[port].global_control_reg);
-       } else {
-               dev_err(&icom_port->adapter->pci_dev->dev,
-                        "Invalid port assignment\n");
-       }
+       /* write flush */
+       readl(stop_proc[port].global_control_reg);
 
+unlock:
        spin_unlock_irqrestore(&icom_lock, flags);
 }
 
@@ -328,23 +328,25 @@ static void start_processor(struct icom_port *icom_port)
        spin_lock_irqsave(&icom_lock, flags);
 
        port = icom_port->port;
+       if (port >= ARRAY_SIZE(start_proc)) {
+               dev_err(&icom_port->adapter->pci_dev->dev,
+                       "Invalid port assignment\n");
+               goto unlock;
+       }
+
        if (port == 0 || port == 1)
                start_proc[port].global_control_reg = &icom_port->global_reg->control;
        else
                start_proc[port].global_control_reg = &icom_port->global_reg->control_2;
-       if (port < 4) {
-               temp = readl(start_proc[port].global_control_reg);
-               temp =
-                       (temp & ~stop_proc[port].processor_id) | start_proc[port].processor_id;
-               writel(temp, start_proc[port].global_control_reg);
 
-               /* write flush */
-               readl(start_proc[port].global_control_reg);
-       } else {
-               dev_err(&icom_port->adapter->pci_dev->dev,
-                        "Invalid port assignment\n");
-       }
+       temp = readl(start_proc[port].global_control_reg);
+       temp = (temp & ~stop_proc[port].processor_id) | start_proc[port].processor_id;
+       writel(temp, start_proc[port].global_control_reg);
+
+       /* write flush */
+       readl(start_proc[port].global_control_reg);
 
+unlock:
        spin_unlock_irqrestore(&icom_lock, flags);
 }
 
@@ -557,6 +559,12 @@ static int startup(struct icom_port *icom_port)
         */
        spin_lock_irqsave(&icom_lock, flags);
        port = icom_port->port;
+       if (port >= ARRAY_SIZE(int_mask_tbl)) {
+               dev_err(&icom_port->adapter->pci_dev->dev,
+                       "Invalid port assignment\n");
+               goto unlock;
+       }
+
        if (port == 0 || port == 1)
                int_mask_tbl[port].global_int_mask = &icom_port->global_reg->int_mask;
        else
@@ -566,17 +574,14 @@ static int startup(struct icom_port *icom_port)
                writew(0x00FF, icom_port->int_reg);
        else
                writew(0x3F00, icom_port->int_reg);
-       if (port < 4) {
-               temp = readl(int_mask_tbl[port].global_int_mask);
-               writel(temp & ~int_mask_tbl[port].processor_id, int_mask_tbl[port].global_int_mask);
 
-               /* write flush */
-               readl(int_mask_tbl[port].global_int_mask);
-       } else {
-               dev_err(&icom_port->adapter->pci_dev->dev,
-                        "Invalid port assignment\n");
-       }
+       temp = readl(int_mask_tbl[port].global_int_mask);
+       writel(temp & ~int_mask_tbl[port].processor_id, int_mask_tbl[port].global_int_mask);
+
+       /* write flush */
+       readl(int_mask_tbl[port].global_int_mask);
 
+unlock:
        spin_unlock_irqrestore(&icom_lock, flags);
        return 0;
 }
@@ -595,21 +600,23 @@ static void shutdown(struct icom_port *icom_port)
         * disable all interrupts
         */
        port = icom_port->port;
+       if (port >= ARRAY_SIZE(int_mask_tbl)) {
+               dev_err(&icom_port->adapter->pci_dev->dev,
+                       "Invalid port assignment\n");
+               goto unlock;
+       }
        if (port == 0 || port == 1)
                int_mask_tbl[port].global_int_mask = &icom_port->global_reg->int_mask;
        else
                int_mask_tbl[port].global_int_mask = &icom_port->global_reg->int_mask_2;
 
-       if (port < 4) {
-               temp = readl(int_mask_tbl[port].global_int_mask);
-               writel(temp | int_mask_tbl[port].processor_id, int_mask_tbl[port].global_int_mask);
+       temp = readl(int_mask_tbl[port].global_int_mask);
+       writel(temp | int_mask_tbl[port].processor_id, int_mask_tbl[port].global_int_mask);
 
-               /* write flush */
-               readl(int_mask_tbl[port].global_int_mask);
-       } else {
-               dev_err(&icom_port->adapter->pci_dev->dev,
-                        "Invalid port assignment\n");
-       }
+       /* write flush */
+       readl(int_mask_tbl[port].global_int_mask);
+
+unlock:
        spin_unlock_irqrestore(&icom_lock, flags);
 
        /*