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/20211007181918.136982-3-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Nghia Le <nghialm78@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/cma.h b/include/linux/cma.h
index 53fd8c3cdbd04441425e857edee39b626fe8563e..bd801023504b29197f103f49030a5fd87c1bf4d7 100644 (file)
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -46,6 +46,7 @@ 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_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);

diff --git a/mm/cma.c b/mm/cma.c
index 995e15480937fee8ceb6e88d0b78b21be8d6a5eb..11152c3fb23ccf4b9376f9e9b1ca30b59b818720 100644 (file)
--- a/mm/cma.c
+++ b/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 struct page *pages,
 {
        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);