ieee1394: mark char device files as not seekable

The
  - raw1394   (/dev/raw1394),
  - video1394 (/dev/video1394/*),
  - dv1394    (/dev/dv1394/*)
character device file ABIs do not make any use of lseek(), pread(), or
pwrite().  Therefore use nonseekable_open() and, redundantly, set
file_operations.llseek to no_llseek to remove any doubt whether the BKL-
grabbing default_llseek handler is used.

Although all this is legacy code which should be left in peace until it
is eventually removed (as it is superseded by firewire-core's
<linux/firewire-cdev.h> ABI), this change seems still worth doing to
further minimize the presence of BKL usage in the kernel.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/ieee1394/dv1394.c b/drivers/ieee1394/dv1394.c
index 9fd4a0d3206e..adaefabc40e9 100644
--- a/drivers/ieee1394/dv1394.c
+++ b/drivers/ieee1394/dv1394.c
@@ -1824,7 +1824,7 @@ static int dv1394_open(struct inode *inode, struct file *file)
                "and will not be available in the new firewire driver stack. "
                "Try libraw1394 based programs instead.\n", current->comm);
 
-        return 0;
+        return nonseekable_open(inode, file);
 }
 
 
@@ -2153,17 +2153,18 @@ static struct cdev dv1394_cdev;
 static const struct file_operations dv1394_fops=
 {
         .owner =        THIS_MODULE,
-        .poll =         dv1394_poll,
+        .poll =         dv1394_poll,
         .unlocked_ioctl = dv1394_ioctl,
 #ifdef CONFIG_COMPAT
         .compat_ioctl = dv1394_compat_ioctl,
 #endif
         .mmap =         dv1394_mmap,
         .open =         dv1394_open,
-        .write =        dv1394_write,
-        .read =         dv1394_read,
+        .write =        dv1394_write,
+        .read =         dv1394_read,
         .release =      dv1394_release,
-        .fasync =       dv1394_fasync,
+        .fasync =       dv1394_fasync,
+        .llseek =       no_llseek,
 };