[PATCH 01/11] mm/cma: drop const for struct page on release API

[Eric Chanudet]

The const is not honored. Both cma_release and cma_release_frozen do a
struct page -> pfn -> struct page round-trip to convert the const struct
page pointer to struct page and modify it:
cma_release calls put_page_testzero() directly, which modifies the page;
cma_release_frozen calls free_contig_frozen_range(pfn),
__free_contig_frozen_range, then __free_contig_range_common which
modifies the page as well.

Signed-off-by: Eric Chanudet <echanude@xxxxxxxxxx>
---
 include/linux/cma.h | 4 ++--
 mm/cma.c            | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/cma.h b/include/linux/cma.h
index 8555d38a97b1..16e2136421b7 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -49,12 +49,12 @@ extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 					struct cma **res_cma);
 extern struct page *cma_alloc(struct cma *cma, unsigned long count, unsigned int align,
 			      bool no_warn);
-extern bool cma_release(struct cma *cma, const struct page *pages, unsigned long count);
+extern bool cma_release(struct cma *cma, struct page *pages, unsigned long count);
 
 struct page *cma_alloc_frozen(struct cma *cma, unsigned long count,
 		unsigned int align, bool no_warn);
 struct page *cma_alloc_frozen_compound(struct cma *cma, unsigned int order);
-bool cma_release_frozen(struct cma *cma, const struct page *pages,
+bool cma_release_frozen(struct cma *cma, struct page *pages,
 		unsigned long count);
 
 extern int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data);
diff --git a/mm/cma.c b/mm/cma.c
index a13ce4999b39..e1820fb451e4 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -992,7 +992,7 @@ static struct cma_memrange *find_cma_memrange(struct cma *cma,
 }
 
 static void __cma_release_frozen(struct cma *cma, struct cma_memrange *cmr,
-		const struct page *pages, unsigned long count)
+		struct page *pages, unsigned long count)
 {
 	unsigned long pfn = page_to_pfn(pages);
 
@@ -1014,7 +1014,7 @@ static void __cma_release_frozen(struct cma *cma, struct cma_memrange *cmr,
  * It returns false when provided pages do not belong to contiguous area and
  * true otherwise.
  */
-bool cma_release(struct cma *cma, const struct page *pages,
+bool cma_release(struct cma *cma, struct page *pages,
 		 unsigned long count)
 {
 	struct cma_memrange *cmr;
@@ -1037,7 +1037,7 @@ bool cma_release(struct cma *cma, const struct page *pages,
 }
 EXPORT_SYMBOL_GPL(cma_release);
 
-bool cma_release_frozen(struct cma *cma, const struct page *pages,
+bool cma_release_frozen(struct cma *cma, struct page *pages,
 		unsigned long count)
 {
 	struct cma_memrange *cmr;

-- 
2.53.0