mm/vmalloc: do not output a spurious warning when huge vmalloc() fails

mm/vmalloc: do not output a spurious warning when huge vmalloc() fails

In __vmalloc_area_node() we always warn_alloc() when an allocation
performed by vm_area_alloc_pages() fails unless it was due to a pending
fatal signal.

However, huge page allocations instigated either by vmalloc_huge() or
__vmalloc_node_range() (or a caller that invokes this like kvmalloc() or
kvmalloc_node()) always falls back to order-0 allocations if the huge page
allocation fails.

This renders the warning useless and noisy, especially as all callers
appear to be aware that this may fallback.  This has already resulted in
at least one bug report from a user who was confused by this (see link).

Therefore, simply update the code to only output this warning for order-0
pages when no fatal signal is pending.

Link: https://bugzilla.suse.com/show_bug.cgi?id=1211410
Link: https://lkml.kernel.org/r/20230605201107.83298-1-lstoakes@gmail.com
Fixes: 80b1d8fdfad1 ("mm: vmalloc: correct use of __GFP_NOWARN mask in __vmalloc_area_node()")
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 95a301eefa82057571207edd06ea36218985a75e)