mm/hugetlb: avoid hardcoding while checking if cma is enabled

hugetlb_cma[0] can be NULL due to various reasons, for example, node0
has no memory.  so NULL hugetlb_cma[0] doesn't necessarily mean cma is
not enabled.  gigantic pages might have been reserved on other nodes.
This patch fixes possible double reservation and CMA leak.

[[email protected]: fix CONFIG_CMA=n warning]
[[email protected]: better checks before using hugetlb_cma]
  Link: http://lkml.kernel.org/r/[email protected]

Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Barry Song <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Mike Kravetz <[email protected]>
Acked-by: Roman Gushchin <[email protected]>
Cc: Jonathan Cameron <[email protected]>
Cc: <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions