mm/mremap: clean up mlock populate behaviour

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When an mlock()'d VMA is expanded, we need to populate the expanded region
to maintain the contract that all mlock()'d memory is present (albeit -
with some period after mmap unlock where the expanded part of the mapping
remains unfaulted).

The current implementation is very unclear, so make it absolutely explicit
under what circumstances we do this.

Link: https://lkml.kernel.org/r/2358b0006baa9cab83db4259817794f16fe1992e.1752770784.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

...

This commit is contained in:

Lorenzo Stoakes 2025-07-17 17:55:58 +01:00 • committed by Andrew Morton

parent 9b2301bf8d

commit 2cf442d742

1 changed files with 8 additions and 5 deletions

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mm/mremap.c

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