Commit dbda8fea authored by Barry Song's avatar Barry Song Committed by Linus Torvalds
Browse files

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



Fixes: cf11e85f ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: default avatarBarry Song <song.bao.hua@hisilicon.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Acked-by: default avatarRoman Gushchin <guro@fb.com>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200710005726.36068-1-song.bao.hua@hisilicon.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d38a2b7a

mm/hugetlb.c

+10 −5
Original line number Diff line number Diff line
@@ -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 page *page, unsigned int order) 
	 * 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(struct hstate *h, gfp_t gfp_mask, 
{

	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(struct hstate *h, gfp_t gfp_mask, 
				return page;

		}

	}

#endif



	return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);

}
@@ -2571,7 +2577,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 


	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 *oldpage, struct page *newpage, int reason) 
}



#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)

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