[PATCH 6/6] vfio: do not set FMODE_LSEEK flag

[PATCH 6/6] vfio: do not set FMODE_LSEEK flag

[Jason A. Donenfeld]

This file does not support llseek, so don't set the flag advertising it.

Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 drivers/vfio/vfio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 61e71c1154be..d194dda89542 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1129,7 +1129,7 @@ static struct file *vfio_device_open(struct vfio_device *device)
 	 * Appears to be missing by lack of need rather than
 	 * explicitly prevented.  Now there's need.
 	 */
-	filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
+	filep->f_mode |= (FMODE_PREAD | FMODE_PWRITE);
 
 	if (device->group->type == VFIO_NO_IOMMU)
 		dev_warn(device->dev, "vfio-noiommu device opened by user "
-- 
2.35.1

Re: [PATCH 6/6] vfio: do not set FMODE_LSEEK flag

[Al Viro]

On Fri, Jun 24, 2022 at 06:56:31PM +0200, Jason A. Donenfeld wrote:
> This file does not support llseek, so don't set the flag advertising it.

... or it could grow a working llseek - doesn't look like it would be
hard to do...

Re: [PATCH 6/6] vfio: do not set FMODE_LSEEK flag

[Jason A. Donenfeld]

On Fri, Jun 24, 2022 at 10:53:19PM +0100, Al Viro wrote:
> On Fri, Jun 24, 2022 at 06:56:31PM +0200, Jason A. Donenfeld wrote:
> > This file does not support llseek, so don't set the flag advertising it.
> 
> ... or it could grow a working llseek - doesn't look like it would be
> hard to do...

I started doing this, but it looks somewhat involved and a bit out of
scope here. vfio_device_ops would need to grow a new member, and then
the various types of vfio devices would need to start using it and so
forth. I'll save that for another series.

Jason