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 7b862df..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)},
@@ -239,9 +243,7 @@ struct moschip_port {
        __u8 shadowMCR;         /* last MCR value received */
        char open;
        char open_ports;
-       char zombie;
        wait_queue_head_t wait_chase;   /* for handling sleeping while waiting for chase to finish */
-       wait_queue_head_t delta_msr_wait;       /* for handling sleeping while waiting for msr change to happen */
        int delta_msr_cond;
        struct async_icount icount;
        struct usb_serial_port *port;   /* loop back to the owner of this object */
@@ -260,6 +262,8 @@ struct moschip_port {
        struct urb *write_urb_pool[NUM_URBS];
        char busy[NUM_URBS];
        bool read_urb_busy;
+
+       unsigned long flags;
 };
 
 
@@ -454,6 +458,9 @@ static void mos7840_handle_new_msr(struct moschip_port *port, __u8 new_msr)
                        icount->rng++;
                        smp_wmb();
                }
+
+               mos7840_port->delta_msr_cond = 1;
+               wake_up_interruptible(&port->port->delta_msr_wait);
        }
 }
 
@@ -518,11 +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);
@@ -535,6 +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,
@@ -545,6 +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 */
@@ -556,6 +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;
 }
 
@@ -642,14 +657,7 @@ static void mos7840_interrupt_callback(struct urb *urb)
                                        wreg = MODEM_STATUS_REGISTER;
                                        break;
                                }
-                               spin_lock(&mos7840_port->pool_lock);
-                               if (!mos7840_port->zombie) {
-                                       rv = mos7840_get_reg(mos7840_port, wval, wreg, &Data);
-                               } else {
-                                       spin_unlock(&mos7840_port->pool_lock);
-                                       return;
-                               }
-                               spin_unlock(&mos7840_port->pool_lock);
+                               rv = mos7840_get_reg(mos7840_port, wval, wreg, &Data);
                        }
                }
        }
@@ -931,20 +939,20 @@ static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port)
        status = mos7840_get_reg_sync(port, mos7840_port->SpRegOffset, &Data);
        if (status < 0) {
                dbg("Reading Spreg failed");
-               return -1;
+               goto err;
        }
        Data |= 0x80;
        status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
        if (status < 0) {
                dbg("writing Spreg failed");
-               return -1;
+               goto err;
        }
 
        Data &= ~0x80;
        status = mos7840_set_reg_sync(port, mos7840_port->SpRegOffset, Data);
        if (status < 0) {
                dbg("writing Spreg failed");
-               return -1;
+               goto err;
        }
        /* End of block to be checked */
 
@@ -953,7 +961,7 @@ static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port)
                                                                        &Data);
        if (status < 0) {
                dbg("Reading Controlreg failed");
-               return -1;
+               goto err;
        }
        Data |= 0x08;           /* Driver done bit */
        Data |= 0x20;           /* rx_disable */
@@ -961,7 +969,7 @@ static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port)
                                mos7840_port->ControlRegOffset, Data);
        if (status < 0) {
                dbg("writing Controlreg failed");
-               return -1;
+               goto err;
        }
        /* do register settings here */
        /* Set all regs to the device default values. */
@@ -972,21 +980,21 @@ static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port)
        status = mos7840_set_uart_reg(port, INTERRUPT_ENABLE_REGISTER, Data);
        if (status < 0) {
                dbg("disabling interrupts failed");
-               return -1;
+               goto err;
        }
        /* Set FIFO_CONTROL_REGISTER to the default value */
        Data = 0x00;
        status = mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);
        if (status < 0) {
                dbg("Writing FIFO_CONTROL_REGISTER  failed");
-               return -1;
+               goto err;
        }
 
        Data = 0xcf;
        status = mos7840_set_uart_reg(port, FIFO_CONTROL_REGISTER, Data);
        if (status < 0) {
                dbg("Writing FIFO_CONTROL_REGISTER  failed");
-               return -1;
+               goto err;
        }
 
        Data = 0x03;
@@ -1123,7 +1131,6 @@ static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port)
 
        /* initialize our wait queues */
        init_waitqueue_head(&mos7840_port->wait_chase);
-       init_waitqueue_head(&mos7840_port->delta_msr_wait);
 
        /* initialize our icount structure */
        memset(&(mos7840_port->icount), 0x00, sizeof(mos7840_port->icount));
@@ -1143,7 +1150,15 @@ static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port)
        dbg ("%s leave", __func__);
 
        return 0;
-
+err:
+       for (j = 0; j < NUM_URBS; ++j) {
+               urb = mos7840_port->write_urb_pool[j];
+               if (!urb)
+                       continue;
+               kfree(urb->transfer_buffer);
+               usb_free_urb(urb);
+       }
+       return status;
 }
 
 /*****************************************************************************
@@ -1509,8 +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",
@@ -1674,7 +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)
@@ -1968,25 +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) {
@@ -2081,8 +2100,6 @@ static void mos7840_change_port_settings(struct tty_struct *tty,
                        mos7840_port->read_urb_busy = false;
                }
        }
-       wake_up(&mos7840_port->delta_msr_wait);
-       mos7840_port->delta_msr_cond = 1;
        dbg("mos7840_change_port_settings mos7840_port->shadowLCR is End %x",
            mos7840_port->shadowLCR);
 }
@@ -2292,13 +2309,18 @@ static int mos7840_ioctl(struct tty_struct *tty,
                while (1) {
                        /* interruptible_sleep_on(&mos7840_port->delta_msr_wait); */
                        mos7840_port->delta_msr_cond = 0;
-                       wait_event_interruptible(mos7840_port->delta_msr_wait,
-                                                (mos7840_port->
+                       wait_event_interruptible(port->delta_msr_wait,
+                                                (port->serial->disconnected ||
+                                                 mos7840_port->
                                                  delta_msr_cond == 1));
 
                        /* see if a signal did it */
                        if (signal_pending(current))
                                return -ERESTARTSYS;
+
+                       if (port->serial->disconnected)
+                               return -EIO;
+
                        cnow = mos7840_port->icount;
                        smp_rmb();
                        if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
@@ -2593,7 +2615,6 @@ error:
 static void mos7840_disconnect(struct usb_serial *serial)
 {
        int i;
-       unsigned long flags;
        struct moschip_port *mos7840_port;
        dbg("%s", " disconnect :entering..........");
 
@@ -2611,9 +2632,6 @@ static void mos7840_disconnect(struct usb_serial *serial)
                mos7840_port = mos7840_get_port_private(serial->port[i]);
                dbg ("mos7840_port %d = %p", i, mos7840_port);
                if (mos7840_port) {
-                       spin_lock_irqsave(&mos7840_port->pool_lock, flags);
-                       mos7840_port->zombie = 1;
-                       spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
                        usb_kill_urb(mos7840_port->control_urb);
                }
        }