Walk list of processes attached to a shared page

[W. Michael Petullo]

Is it possible to walk the processes already attached to a shared page
in an implementation of security_shm_shmat()?

I have a function:

	static int my_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr,
				int shmflag)

and I would like to find the processes already attached.

It seems like rmap_walk() would help, but I cannot figure out how to
get an appropriate struct page out of a struct shmid_kernel or unmapped
address (i.e., shmaddr above).

-- 
Mike

:wq