maple_tree: fix allocation in mas_sparse_area()

In the case of reverse allocation, mas->index and mas->last do not point
to the correct allocation range, which will cause users to get incorrect
allocation results, so fix it.  If the user does not use it in a specific
way, this bug will not be triggered.

This is a bug, but only VMA uses it now, the way VMA is used now will
not trigger it.  There is a possibility that a user will trigger it in
the future.

Also re-check whether the size is still satisfied after the lower bound
was increased, which is a corner case and is incorrect in previous
versions.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions