mm/hugetlb: move hugetlb CMA code in to its own file

hugetlb.c contained a number of CONFIG_CMA ifdefs, and the code inside
them was large enough to merit being in its own file, so move it, cleaning
up things a bit.

Hide some direct variable access behind functions to accommodate the move.

No functional change intended.

Link: https://lkml.kernel.org/r/20250228182928.2645936-28-fvdl@google.com
Signed-off-by: Frank van der Linden <fvdl@google.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/mm/hugetlb_cma.h b/mm/hugetlb_cma.h
new file mode 100644
index 000000000000..f7d7fb9880a2
--- /dev/null
+++ b/mm/hugetlb_cma.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_HUGETLB_CMA_H
+#define _LINUX_HUGETLB_CMA_H
+
+#ifdef CONFIG_CMA
+void hugetlb_cma_free_folio(struct folio *folio);
+struct folio *hugetlb_cma_alloc_folio(struct hstate *h, gfp_t gfp_mask,
+				      int nid, nodemask_t *nodemask);
+struct huge_bootmem_page *hugetlb_cma_alloc_bootmem(struct hstate *h, int *nid,
+						    bool node_exact);
+void hugetlb_cma_check(void);
+bool hugetlb_cma_exclusive_alloc(void);
+unsigned long hugetlb_cma_total_size(void);
+void hugetlb_cma_validate_params(void);
+bool hugetlb_early_cma(struct hstate *h);
+#else
+static inline void hugetlb_cma_free_folio(struct folio *folio)
+{
+}
+
+static inline struct folio *hugetlb_cma_alloc_folio(struct hstate *h,
+	    gfp_t gfp_mask, int nid, nodemask_t *nodemask)
+{
+	return NULL;
+}
+
+static inline
+struct huge_bootmem_page *hugetlb_cma_alloc_bootmem(struct hstate *h, int *nid,
+						    bool node_exact)
+{
+	return NULL;
+}
+
+static inline void hugetlb_cma_check(void)
+{
+}
+
+static inline bool hugetlb_cma_exclusive_alloc(void)
+{
+	return false;
+}
+
+static inline unsigned long hugetlb_cma_total_size(void)
+{
+	return 0;
+}
+
+static inline void hugetlb_cma_validate_params(void)
+{
+}
+
+static inline bool hugetlb_early_cma(struct hstate *h)
+{
+	return false;
+}
+#endif
+#endif