DMA, CMA: fix possible memory leak

We should free memory for bitmap when we find zone mismatch, otherwise
this memory will leak.

Additionally, I copy code comment from PPC KVM's CMA code to inform why
we need to check zone mis-match.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: Michal Nazarewicz <mina86@mina86.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Alexander Graf <agraf@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
index 83969f8c5727..6467c919c509 100644
--- a/drivers/base/dma-contiguous.c
+++ b/drivers/base/dma-contiguous.c
@@ -176,14 +176,24 @@ static int __init cma_activate_area(struct cma *cma)
                 base_pfn = pfn;
                 for (j = pageblock_nr_pages; j; --j, pfn++) {
                         WARN_ON_ONCE(!pfn_valid(pfn));
+                        /*
+                         * alloc_contig_range requires the pfn range
+                         * specified to be in the same zone. Make this
+                         * simple by forcing the entire CMA resv range
+                         * to be in the same zone.
+                         */
                         if (page_zone(pfn_to_page(pfn)) != zone)
-                                return -EINVAL;
+                                goto err;
                 }
                 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
         } while (--i);
 
         mutex_init(&cma->lock);
         return 0;
+
+err:
+        kfree(cma->bitmap);
+        return -EINVAL;
 }
 
 static struct cma cma_areas[MAX_CMA_AREAS];