On Mon 11-09-17 13:10:30, Christoph Hellwig wrote: > On Mon, Sep 11, 2017 at 11:47:14AM +0200, Jan Kara wrote: > > On Fri 08-09-17 12:35:13, Dan Williams wrote: > > > The mmap(2) syscall suffers from the ABI anti-pattern of not validating > > > unknown flags. However, proposals like MAP_SYNC and MAP_DIRECT need a > > > mechanism to define new behavior that is known to fail on older kernels > > > without the support. Define a new MAP_SHARED_VALIDATE flag pattern that > > > is guaranteed to fail on all legacy mmap implementations. > > > > > > With this in place new flags can be defined as: > > > > > > #define MAP_new (MAP_SHARED_VALIDATE | val) > > > > Is this changelog stale? Given MAP_SHARED_VALIDATE will be new mapping > > type, I'd expect we define new flags just as any other mapping flags... > > I see no reason why MAP_SHARED_VALIDATE should be or'ed to that. > > Btw, I still think it should be a new hidden flag and not a new mapping > type. I brought this up last time, so maybe I missed the answer > to my concern. Hum, I don't remember your concern and the only comment from you to the last posting which I've found is: "no mmap3 syscall here :) Do you also need to update the nommu mmap implementation?" So I guess it's something else. So can you remind me or send a link? Thanks! Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
