[129/262] mm/cma: add cma_pages_valid to determine if pages are in CMA

Commit Message

Andrew Morton Nov. 5, 2021, 8:41 p.m. UTC

From: Mike Kravetz <[e-mail]>
Subject: mm/cma: add cma_pages_valid to determine if pages are in CMA

Add new interface cma_pages_valid() which indicates if the specified pages
are part of a CMA region.  This interface will be used in a subsequent
patch by hugetlb code.

In order to keep the same amount of DEBUG information, a pr_debug() call
was added to cma_pages_valid().  In the case where the page passed to
cma_release is not in cma region, the debug message will be printed from
cma_pages_valid as opposed to cma_release.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Mike Kravetz <[e-mail]>
Acked-by: David Hildenbrand <[e-mail]>
Reviewed-by: Oscar Salvador <[e-mail]>
Cc: "Aneesh Kumar K . V" <[e-mail]>
Cc: David Rientjes <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Muchun Song <[e-mail]>
Cc: Naoya Horiguchi <[e-mail]>
Cc: Nghia Le <[e-mail]>
Cc: Zi Yan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 include/linux/cma.h |    1 +
 mm/cma.c            |   24 ++++++++++++++++++++----
 2 files changed, 21 insertions(+), 4 deletions(-)

Patch

--- a/include/linux/cma.h~mm-cma-add-cma_pages_valid-to-determine-if-pages-are-in-cma
+++ a/include/linux/cma.h
@@ -46,6 +46,7 @@  extern int cma_init_reserved_mem(phys_ad
 					struct cma **res_cma);
 extern struct page *cma_alloc(struct cma *cma, unsigned long count, unsigned int align,
 			      bool no_warn);
+extern bool cma_pages_valid(struct cma *cma, const struct page *pages, unsigned long count);
 extern bool cma_release(struct cma *cma, const struct page *pages, unsigned long count);
 
 extern int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data);
--- a/mm/cma.c~mm-cma-add-cma_pages_valid-to-determine-if-pages-are-in-cma
+++ a/mm/cma.c
@@ -524,6 +524,25 @@  out:
 	return page;
 }
 
+bool cma_pages_valid(struct cma *cma, const struct page *pages,
+		     unsigned long count)
+{
+	unsigned long pfn;
+
+	if (!cma || !pages)
+		return false;
+
+	pfn = page_to_pfn(pages);
+
+	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) {
+		pr_debug("%s(page %p, count %lu)\n", __func__,
+						(void *)pages, count);
+		return false;
+	}
+
+	return true;
+}
+
 /**
  * cma_release() - release allocated pages
  * @cma:   Contiguous memory region for which the allocation is performed.
@@ -539,16 +558,13 @@  bool cma_release(struct cma *cma, const
 {
 	unsigned long pfn;
 
-	if (!cma || !pages)
+	if (!cma_pages_valid(cma, pages, count))
 		return false;
 
 	pr_debug("%s(page %p, count %lu)\n", __func__, (void *)pages, count);
 
 	pfn = page_to_pfn(pages);
 
-	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
-		return false;
-
 	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
 
 	free_contig_range(pfn, count);