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is eventually removed (as it is superseded by firewire-core's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, 3 insertions, 2 deletions

diff --git a/drivers/ieee1394/video1394.c b/drivers/ieee1394/video1394.c
index 949064a05675..a42bd6893bcf 100644
--- a/drivers/ieee1394/video1394.c
+++ b/drivers/ieee1394/video1394.c
@@ -1239,7 +1239,7 @@ static int video1394_open(struct inode *inode, struct file *file)
         ctx->current_ctx = NULL;
         file->private_data = ctx;
 
-        return 0;
+        return nonseekable_open(inode, file);
 }
 
 static int video1394_release(struct inode *inode, struct file *file)
@@ -1287,7 +1287,8 @@ static const struct file_operations video1394_fops=
         .poll =         video1394_poll,
         .mmap =         video1394_mmap,
         .open =         video1394_open,
-        .release =      video1394_release
+        .release =      video1394_release,
+        .llseek =       no_llseek,
 };
 
 /*** HOTPLUG STUFF **********************************************************/