linux-kernel - [PATCH 2/6] dma-direct: use __GFP_ZERO in dma_direct_alloc

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Message-Id: <20201124153845.132207-2-ribalda@chromium.org>
Date:   Tue, 24 Nov 2020 16:38:41 +0100
From:   Ricardo Ribalda <ribalda@...omium.org>
To:     Christoph Hellwig <hch@....de>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        IOMMU DRIVERS <iommu@...ts.linux-foundation.org>,
        Joerg Roedel <joro@...tes.org>,
        Robin Murphy <robin.murphy@....com>,
        Linux Doc Mailing List <linux-doc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        Tomasz Figa <tfiga@...omium.org>,
        Sergey Senozhatsky <senozhatsky@...gle.com>
Subject: [PATCH 2/6] dma-direct: use __GFP_ZERO in dma_direct_alloc_pages

From: Christoph Hellwig <hch@....de>

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 | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 06c111544f61..76c741e610fc 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -280,13 +280,12 @@ 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 (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
 	    force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp))
 		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 
-	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)) {
@@ -300,13 +299,11 @@ 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);
 	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
 	return page;
 out_free_pages:
-- 
2.29.2.454.gaff20da3a2-goog