USB: serial: mos7840: fix non-atomic allocation in write path

[pandora-kernel.git] / drivers / usb / serial / mos7840.c

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 5e8c736..59fdb84 100644 (file)
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -185,6 +185,10 @@
 #define URB_TRANSFER_BUFFER_SIZE        32     /* URB Size  */
 
 
+enum mos7840_flag {
+       MOS7840_FLAG_CTRL_BUSY,
+};
+
 static const struct usb_device_id moschip_port_id_table[] = {
        {USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7840)},
        {USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7820)},
@@ -258,6 +262,8 @@ struct moschip_port {
        struct urb *write_urb_pool[NUM_URBS];
        char busy[NUM_URBS];
        bool read_urb_busy;
+
+       unsigned long flags;
 };
 
 
@@ -519,11 +525,11 @@ static void mos7840_control_callback(struct urb *urb)
                /* this urb is terminated, clean up */
                dbg("%s - urb shutting down with status: %d", __func__,
                    status);
-               return;
+               goto out;
        default:
                dbg("%s - nonzero urb status received: %d", __func__,
                    status);
-               return;
+               goto out;
        }
 
        dbg("%s urb buffer size is %d", __func__, urb->actual_length);
@@ -536,6 +542,8 @@ static void mos7840_control_callback(struct urb *urb)
                mos7840_handle_new_msr(mos7840_port, regval);
        else if (mos7840_port->MsrLsr == 1)
                mos7840_handle_new_lsr(mos7840_port, regval);
+out:
+       clear_bit_unlock(MOS7840_FLAG_CTRL_BUSY, &mos7840_port->flags);
 }
 
 static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg,
@@ -546,6 +554,9 @@ static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg,
        unsigned char *buffer = mcs->ctrl_buf;
        int ret;
 
+       if (test_and_set_bit_lock(MOS7840_FLAG_CTRL_BUSY, &mcs->flags))
+               return -EBUSY;
+
        dr->bRequestType = MCS_RD_RTYPE;
        dr->bRequest = MCS_RDREQ;
        dr->wValue = cpu_to_le16(Wval); /* 0 */
@@ -557,6 +568,9 @@ static int mos7840_get_reg(struct moschip_port *mcs, __u16 Wval, __u16 reg,
                             mos7840_control_callback, mcs);
        mcs->control_urb->transfer_buffer_length = 2;
        ret = usb_submit_urb(mcs->control_urb, GFP_ATOMIC);
+       if (ret)
+               clear_bit_unlock(MOS7840_FLAG_CTRL_BUSY, &mcs->flags);
+
        return ret;
 }
 
@@ -1510,8 +1524,8 @@ static int mos7840_write(struct tty_struct *tty, struct usb_serial_port *port,
        }
 
        if (urb->transfer_buffer == NULL) {
-               urb->transfer_buffer =
-                   kmalloc(URB_TRANSFER_BUFFER_SIZE, GFP_KERNEL);
+               urb->transfer_buffer = kmalloc(URB_TRANSFER_BUFFER_SIZE,
+                                              GFP_ATOMIC);
 
                if (urb->transfer_buffer == NULL) {
                        dev_err(&port->dev, "%s no more kernel memory...\n",
@@ -1675,7 +1689,11 @@ static int mos7840_tiocmget(struct tty_struct *tty)
                return -ENODEV;
 
        status = mos7840_get_uart_reg(port, MODEM_STATUS_REGISTER, &msr);
+       if (status != 1)
+               return -EIO;
        status = mos7840_get_uart_reg(port, MODEM_CONTROL_REGISTER, &mcr);
+       if (status != 1)
+               return -EIO;
        result = ((mcr & MCR_DTR) ? TIOCM_DTR : 0)
            | ((mcr & MCR_RTS) ? TIOCM_RTS : 0)
            | ((mcr & MCR_LOOPBACK) ? TIOCM_LOOP : 0)
@@ -1969,25 +1987,25 @@ static void mos7840_change_port_settings(struct tty_struct *tty,
        iflag = tty->termios->c_iflag;
 
        /* Change the number of bits */
-       if (cflag & CSIZE) {
-               switch (cflag & CSIZE) {
-               case CS5:
-                       lData = LCR_BITS_5;
-                       break;
+       switch (cflag & CSIZE) {
+       case CS5:
+               lData = LCR_BITS_5;
+               break;
 
-               case CS6:
-                       lData = LCR_BITS_6;
-                       break;
+       case CS6:
+               lData = LCR_BITS_6;
+               break;
 
-               case CS7:
-                       lData = LCR_BITS_7;
-                       break;
-               default:
-               case CS8:
-                       lData = LCR_BITS_8;
-                       break;
-               }
+       case CS7:
+               lData = LCR_BITS_7;
+               break;
+
+       default:
+       case CS8:
+               lData = LCR_BITS_8;
+               break;
        }
+
        /* Change the Parity bit */
        if (cflag & PARENB) {
                if (cflag & PARODD) {