dma-direct: re-encrypt memory if dma_direct_alloc_pages() fails

If arch_dma_set_uncached() fails after memory has been decrypted, it needs
to be re-encrypted before freeing.

Fixes: fa7e2247 ("dma-direct: make uncached_kernel_address more general")
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

kernel/dma/direct.c

@@ -220,7 +220,7 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
 		arch_dma_prep_coherent(page, size);
 		ret = arch_dma_set_uncached(ret, size);
 		if (IS_ERR(ret))
-			goto out_free_pages;
+			goto out_encrypt_pages;
 	}
 done:
 	if (force_dma_unencrypted(dev))
@@ -228,6 +228,11 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
 	else
 		*dma_handle = phys_to_dma(dev, page_to_phys(page));
 	return ret;
+
+out_encrypt_pages:
+	if (force_dma_unencrypted(dev))
+		set_memory_encrypted((unsigned long)page_address(page),
+				     1 << get_order(size));
 out_free_pages:
 	dma_free_contiguous(dev, page, size);
 	return NULL;