mm/vmalloc: check various alignments when debugging

Before we did not guarantee a free block with lowest start address for
allocations with alignment >= PAGE_SIZE.  Because an alignment overhead
was included into a search length like below:

     length = size + align - 1;

doing so we make sure that a bigger block would fit after applying an
alignment adjustment.  Now there is no such limitation, i.e.  any
alignment that user wants to apply will result to a lowest address of
returned free area.

Link: https://lkml.kernel.org/r/20211004142829.22222-2-urezki@gmail.com


Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Ping Fang <pifang@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>