proc: nommu: fix empty /proc/<pid>/maps

On no-MMU, /proc/<pid>/maps reads as an empty file.  This happens because
find_vma(mm, 0) always returns NULL (assuming no vma actually contains the
zero address, which is normally the case).

To fix this bug and improve the maintainability in the future, this patch
makes the no-MMU implementation as similar as possible to the MMU
implementation.

The only remaining differences are the lack of hold/release_task_mempolicy
and the extra code to shoehorn the gate vma into the iterator.

This has been tested on top of 6.5.3 on an STM32F746.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 0c563f148043 ("proc: remove VMA rbtree use from nommu")
Signed-off-by: Ben Wolsieffer <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Giulio Benetti <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions