From: Barry Song song.bao.hua@hisilicon.com Subject: 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.

[akpm@linux-foundation.org: fix CONFIG_CMA=n warning] [sfr@canb.auug.org.au: better checks before using hugetlb_cma] Link: http://lkml.kernel.org/r/20200721205716.6dbaa56b@canb.auug.org.au Link: http://lkml.kernel.org/r/20200710005726.36068-1-song.bao.hua@hisilicon.com Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma") Signed-off-by: Barry Song song.bao.hua@hisilicon.com Acked-by: Roman Gushchin guro@fb.com Reviewed-by: Mike Kravetz mike.kravetz@oracle.com Cc: Jonathan Cameron jonathan.cameron@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/hugetlb.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)

--- a/mm/hugetlb.c~mm-hugetlb-avoid-hardcoding-while-checking-if-cma-is-enabled +++ a/mm/hugetlb.c @@ -45,7 +45,10 @@ int hugetlb_max_hstate __read_mostly; unsigned int default_hstate_idx; struct hstate hstates[HUGE_MAX_HSTATE];

+#ifdef CONFIG_CMA static struct cma *hugetlb_cma[MAX_NUMNODES]; +#endif +static unsigned long hugetlb_cma_size __initdata;

/* * Minimum page order among possible hugepage sizes, set to a proper value @@ -1235,9 +1238,10 @@ static void free_gigantic_page(struct pa * If the page isn't allocated using the cma allocator, * cma_release() returns false. */ - if (IS_ENABLED(CONFIG_CMA) && - cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order)) +#ifdef CONFIG_CMA + if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order)) return; +#endif

free_contig_range(page_to_pfn(page), 1 << order); } @@ -1248,7 +1252,8 @@ static struct page *alloc_gigantic_page( { unsigned long nr_pages = 1UL << huge_page_order(h);

- if (IS_ENABLED(CONFIG_CMA)) { +#ifdef CONFIG_CMA + { struct page *page; int node;

@@ -1262,6 +1267,7 @@ static struct page *alloc_gigantic_page( return page; } } +#endif

return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask); } @@ -2571,7 +2577,7 @@ static void __init hugetlb_hstate_alloc_

for (i = 0; i < h->max_huge_pages; ++i) { if (hstate_is_gigantic(h)) { - if (IS_ENABLED(CONFIG_CMA) && hugetlb_cma[0]) { + if (hugetlb_cma_size) { pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n"); break; } @@ -5654,7 +5660,6 @@ void move_hugetlb_state(struct page *old }

#ifdef CONFIG_CMA -static unsigned long hugetlb_cma_size __initdata; static bool cma_reserve_called __initdata;

static int __init cmdline_parse_hugetlb_cma(char *p) _