staging: comedi: fix oops for USB DAQ devices.

commit 3ffab428f40849ed5f21bcfd7285bdef7902f9ca upstream.

This fixes kernel oops when an USB DAQ device is plugged out while it's
communicating with the userspace software.

Signed-off-by: Bernd Porr <berndporr@f2s.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 80a1071bc3211ef3819c7a9e5e201450fcbee8d2..7bd7436c50c964044cde2645d944fa8926677a87 100644 (file)
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1396,9 +1396,6 @@ static struct vm_operations_struct comedi_vm_ops = {
 static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
 {
        const unsigned minor = iminor(file->f_dentry->d_inode);
-       struct comedi_device_file_info *dev_file_info =
-           comedi_get_device_file_info(minor);
-       struct comedi_device *dev = dev_file_info->device;
        struct comedi_async *async = NULL;
        unsigned long start = vma->vm_start;
        unsigned long size;
@@ -1406,6 +1403,15 @@ static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
        int i;
        int retval;
        struct comedi_subdevice *s;
+       struct comedi_device_file_info *dev_file_info;
+       struct comedi_device *dev;
+
+       dev_file_info = comedi_get_device_file_info(minor);
+       if (dev_file_info == NULL)
+               return -ENODEV;
+       dev = dev_file_info->device;
+       if (dev == NULL)
+               return -ENODEV;
 
        mutex_lock(&dev->mutex);
        if (!dev->attached) {
@@ -1472,11 +1478,17 @@ static unsigned int comedi_poll(struct file *file, poll_table * wait)
 {
        unsigned int mask = 0;
        const unsigned minor = iminor(file->f_dentry->d_inode);
-       struct comedi_device_file_info *dev_file_info =
-           comedi_get_device_file_info(minor);
-       struct comedi_device *dev = dev_file_info->device;
        struct comedi_subdevice *read_subdev;
        struct comedi_subdevice *write_subdev;
+       struct comedi_device_file_info *dev_file_info;
+       struct comedi_device *dev;
+       dev_file_info = comedi_get_device_file_info(minor);
+
+       if (dev_file_info == NULL)
+               return -ENODEV;
+       dev = dev_file_info->device;
+       if (dev == NULL)
+               return -ENODEV;
 
        mutex_lock(&dev->mutex);
        if (!dev->attached) {
@@ -1522,9 +1534,15 @@ static ssize_t comedi_write(struct file *file, const char *buf, size_t nbytes,
        int n, m, count = 0, retval = 0;
        DECLARE_WAITQUEUE(wait, current);
        const unsigned minor = iminor(file->f_dentry->d_inode);
-       struct comedi_device_file_info *dev_file_info =
-           comedi_get_device_file_info(minor);
-       struct comedi_device *dev = dev_file_info->device;
+       struct comedi_device_file_info *dev_file_info;
+       struct comedi_device *dev;
+       dev_file_info = comedi_get_device_file_info(minor);
+
+       if (dev_file_info == NULL)
+               return -ENODEV;
+       dev = dev_file_info->device;
+       if (dev == NULL)
+               return -ENODEV;
 
        if (!dev->attached) {
                DPRINTK("no driver configured on comedi%i\n", dev->minor);
@@ -1624,9 +1642,15 @@ static ssize_t comedi_read(struct file *file, char *buf, size_t nbytes,
        int n, m, count = 0, retval = 0;
        DECLARE_WAITQUEUE(wait, current);
        const unsigned minor = iminor(file->f_dentry->d_inode);
-       struct comedi_device_file_info *dev_file_info =
-           comedi_get_device_file_info(minor);
-       struct comedi_device *dev = dev_file_info->device;
+       struct comedi_device_file_info *dev_file_info;
+       struct comedi_device *dev;
+       dev_file_info = comedi_get_device_file_info(minor);
+
+       if (dev_file_info == NULL)
+               return -ENODEV;
+       dev = dev_file_info->device;
+       if (dev == NULL)
+               return -ENODEV;
 
        if (!dev->attached) {
                DPRINTK("no driver configured on comedi%i\n", dev->minor);
@@ -1819,11 +1843,17 @@ ok:
 static int comedi_close(struct inode *inode, struct file *file)
 {
        const unsigned minor = iminor(inode);
-       struct comedi_device_file_info *dev_file_info =
-           comedi_get_device_file_info(minor);
-       struct comedi_device *dev = dev_file_info->device;
        struct comedi_subdevice *s = NULL;
        int i;
+       struct comedi_device_file_info *dev_file_info;
+       struct comedi_device *dev;
+       dev_file_info = comedi_get_device_file_info(minor);
+
+       if (dev_file_info == NULL)
+               return -ENODEV;
+       dev = dev_file_info->device;
+       if (dev == NULL)
+               return -ENODEV;
 
        mutex_lock(&dev->mutex);
 
@@ -1857,10 +1887,15 @@ static int comedi_close(struct inode *inode, struct file *file)
 static int comedi_fasync(int fd, struct file *file, int on)
 {
        const unsigned minor = iminor(file->f_dentry->d_inode);
-       struct comedi_device_file_info *dev_file_info =
-           comedi_get_device_file_info(minor);
+       struct comedi_device_file_info *dev_file_info;
+       struct comedi_device *dev;
+       dev_file_info = comedi_get_device_file_info(minor);
 
-       struct comedi_device *dev = dev_file_info->device;
+       if (dev_file_info == NULL)
+               return -ENODEV;
+       dev = dev_file_info->device;
+       if (dev == NULL)
+               return -ENODEV;
 
        return fasync_helper(fd, file, on, &dev->async_queue);
 }