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is eventually removed (as it is superseded by firewire-core's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,
 };