linux-kernel - [PATCH 5.15 310/667] dma-direct: factor out a helper for DMA_ATTR_NO_KERNEL

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Message-Id: <20220607164944.071964936@linuxfoundation.org>
Date:   Tue,  7 Jun 2022 18:59:35 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Christoph Hellwig <hch@....de>,
        Robin Murphy <robin.murphy@....com>,
        David Rientjes <rientjes@...gle.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 310/667] dma-direct: factor out a helper for DMA_ATTR_NO_KERNEL_MAPPING allocations

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

[ Upstream commit d541ae55d538265861ef729a64d2d816d34ef1e2 ]

Split the code for DMA_ATTR_NO_KERNEL_MAPPING allocations into a separate
helper to make dma_direct_alloc a little more readable.

Signed-off-by: Christoph Hellwig <hch@....de>
Reviewed-by: Robin Murphy <robin.murphy@....com>
Acked-by: David Rientjes <rientjes@...gle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 kernel/dma/direct.c | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 4c6c5e0635e3..ddaac01f2cba 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -149,6 +149,24 @@ static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
 	return ret;
 }
 
+static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, gfp_t gfp)
+{
+	struct page *page;
+
+	page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
+	if (!page)
+		return NULL;
+
+	/* remove any dirty cache lines on the kernel alias */
+	if (!PageHighMem(page))
+		arch_dma_prep_coherent(page, size);
+
+	/* return the page pointer as the opaque cookie */
+	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
+	return page;
+}
+
 void *dma_direct_alloc(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
 {
@@ -161,17 +179,8 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 		gfp |= __GFP_NOWARN;
 
 	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
-	    !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev)) {
-		page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
-		if (!page)
-			return NULL;
-		/* remove any dirty cache lines on the kernel alias */
-		if (!PageHighMem(page))
-			arch_dma_prep_coherent(page, size);
-		*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
-		/* return the page pointer as the opaque cookie */
-		return page;
-	}
+	    !force_dma_unencrypted(dev) && !is_swiotlb_for_alloc(dev))
+		return dma_direct_alloc_no_mapping(dev, size, dma_handle, gfp);
 
 	if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
 	    !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
-- 
2.35.1