st: use noop_llseek() instead of default_llseek()

st_open() suggests that llseek() doesn't work: "We really want to do
nonseekable_open(inode, filp); here, but some versions of tar incorrectly
call lseek on tapes and bail out if that fails.  So we disallow pread()
and pwrite(), but permit lseeks."

Instead of using the fallback default_llseek() the driver should use
noop_llseek() which leaves the file->f_pos untouched but succeeds.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Kai Makisara <Kai.Makisara@kolumbus.fi>
Cc: Willem Riede <osst@riede.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 3ea1a713ef250fcc35a64b10c71a65ac73ea6e42..24211d0efa6d5d82557dac4e6047c3b9efc25c3f 100644 (file)
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -3962,6 +3962,7 @@ static const struct file_operations st_fops =
        .open =         st_open,
        .flush =        st_flush,
        .release =      st_release,
+       .llseek =       noop_llseek,
 };
 
 static int st_probe(struct device *dev)