drivers/base: wrong return value of dmam_declare_coherent_memory

Hi guys,
I found an issue in managed version of dma_declare_coherent_memory, i.e. in dmam_declare_coherent_memory. It looks like the return value of dma_declare_coherent_memory is zero in case of error and a requested flag on success, which dmam_* version doesn't take into account and this leads to leaking of resources.

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Yours sincerely,
Vyacheslav V. Yurkov

P.S.: I'm not subscribed to the maillist, so please include me in CC when responding to this Email.

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--- linux-4.5.2/drivers/base/dma-mapping.c.orig 2016-04-20
08:46:35.000000000 +0200
+++ linux-4.5.2/drivers/base/dma-mapping.c 2016-04-28 10:15:34.295080491
+0200
@@ -198,10 +198,15 @@ int dmam_declare_coherent_memory(struct

rc = dma_declare_coherent_memory(dev, phys_addr, device_addr, size,
flags);
- if (rc == 0)
+
+ if ((flags & DMA_MEMORY_MAP) == DMA_MEMORY_MAP ||
+ (flags & DMA_MEMORY_IO) == DMA_MEMORY_IO) {
devres_add(dev, res);
- else
+ rc = 0;
+ } else {
devres_free(res);
+ rc = -ENOMEM;
+ }

return rc;
}