Re: [PATCH 1/4] ipc/shm: do not check for MAP_POPULATE

Hugh Dickins
2017-02-10T02:25:48Z

On Thu, 9 Feb 2017, Davidlohr Bueso wrote:

> We do not support prefaulting functionality in sysv shm,
> nor MAP_NONBLOCK for that matter. Drop the pointless check
> for populate in do_shmat().

I haven't checked, but are you sure that "populated" does nothing
when the attacher had previously called mlockall(MCL_FUTURE)?

Hugh

>
> Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
> ---
> ipc/shm.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/ipc/shm.c b/ipc/shm.c
> index 06ea9ef7f54a..6b3769967789 100644
> --- a/ipc/shm.c
> +++ b/ipc/shm.c
> @@ -1234,8 +1234,6 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg,
> err = (long)addr;
> invalid:
> up_write(&current->mm->mmap_sem);
> - if (populate)
> - mm_populate(addr, populate);
>
> out_fput:
> fput(file);
> --
> 2.6.6