linux-kernel - [PATCH 4/8] dma-direct: use __GFP_ZERO in dma_direct_alloc

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Message-Id: <20200930160917.1234225-5-hch@lst.de>
Date:   Wed, 30 Sep 2020 18:09:13 +0200
From:   Christoph Hellwig <hch@....de>
To:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Tomasz Figa <tfiga@...omium.org>,
        iommu@...ts.linux-foundation.org
Cc:     Robin Murphy <robin.murphy@....com>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org
Subject: [PATCH 4/8] dma-direct: use __GFP_ZERO in dma_direct_alloc_pages

Prepare for supporting the DMA_ATTR_NO_KERNEL_MAPPING flag in
dma_alloc_pages.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 kernel/dma/direct.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index b5f20781d3a96f..b5d56810130b22 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -296,9 +296,10 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
 {
 	struct page *page;
-	void *ret;
 
 	if (dma_should_alloc_from_pool(dev, gfp, 0)) {
+		void *ret;
+
 		page = dma_alloc_from_pool(dev, size, &ret, gfp,
 				dma_coherent_ok);
 		if (!page)
@@ -306,7 +307,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 		goto done;
 	}
 
-	page = __dma_direct_alloc_pages(dev, size, gfp);
+	page = __dma_direct_alloc_pages(dev, size, gfp | __GFP_ZERO);
 	if (!page)
 		return NULL;
 	if (PageHighMem(page)) {
@@ -320,13 +321,11 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 		goto out_free_pages;
 	}
 
-	ret = page_address(page);
 	if (force_dma_unencrypted(dev)) {
-		if (set_memory_decrypted((unsigned long)ret,
+		if (set_memory_decrypted((unsigned long)page_address(page),
 				1 << get_order(size)))
 			goto out_free_pages;
 	}
-	memset(ret, 0, size);
 done:
 	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
 	return page;
-- 
2.28.0