On Wed, Sep 5, 2018 at 11:09 AM, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote: > What's the reserved for? On 64 bit systems there is a 4 byte struct > hole between weak_count and reserved. There's many more pieces of information that we hold for a node. While we don't have a use for most of that now, we may want some of it in the future, and so I thought it would be wise to reserve some space here so we don't need a new ioctl when that happens. I'm actually not sure it's common to do things this way. > Why not just make reserved a > __u32 and get rid of the hole? (Not rhetorical, I have no idea). Because I thought 8 bytes of reserved space would be nice :-) But you have a good point re:alignment, I should make it two __u32's then. > > Btw, people sometimes complain about that we don't check that user input > is zeroed in ioctls. Like for example maybe they're passing random data > in the the strong_count field and then later we decide that actually > that field should mean something but we can't make it mean anything > because we've been letting the user put whatever they want there. These > are just random thoughts in my head, not necessarily important. That's a good point, I will change the code to check for that. Thanks, Martijn > > regards, > dan carpenter > _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
