Re: [PATCH] mm: remove unnecessary __get_user_pages_unlocked() calls

From: Michal Hocko
Date: Wed Oct 26 2016 - 05:16:21 EST


On Wed 26-10-16 00:46:31, Lorenzo Stoakes wrote:
> The holdout for unexporting __get_user_pages_unlocked() is its invocation in
> mm/process_vm_access.c: process_vm_rw_single_vec(), as this definitely _does_
> seem to invoke VM_FAULT_RETRY behaviour which get_user_pages_remote() will not
> trigger if we were to replace it with the latter.

I am not sure I understand. Prior to 1e9877902dc7e this used
get_user_pages_unlocked. What prevents us from reintroducing it with
FOLL_REMOVE which was meant to be added by the above commit?

Or am I missing your point?
--
Michal Hocko
SUSE Labs