linux-kernel - [PATCH 5.15 311/667] dma-direct: dont fail on highmem CMA pages in dma_direct_alloc

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Message-Id: <20220607164944.101702481@linuxfoundation.org>
Date:   Tue,  7 Jun 2022 18:59:36 +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, Mark ONeill <mao@...blingdice.co.uk>,
        Christoph Hellwig <hch@....de>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 311/667] dma-direct: dont fail on highmem CMA pages in dma_direct_alloc_pages

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

[ Upstream commit 92826e967535db2eb117db227b1191aaf98e4bb3 ]

When dma_direct_alloc_pages encounters a highmem page it just gives up
currently.  But what we really should do is to try memory using the
page allocator instead - without this platforms with a global highmem
CMA pool will fail all dma_alloc_pages allocations.

Fixes: efa70f2fdc84 ("dma-mapping: add a new dma_alloc_pages API")
Reported-by: Mark O'Neill <mao@...blingdice.co.uk>
Signed-off-by: Christoph Hellwig <hch@....de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 kernel/dma/direct.c | 27 ++++++++++-----------------
 1 file changed, 10 insertions(+), 17 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index ddaac01f2cba..a1573ed2ea18 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -85,7 +85,7 @@ static void __dma_direct_free_pages(struct device *dev, struct page *page,
 }
 
 static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
-		gfp_t gfp)
+		gfp_t gfp, bool allow_highmem)
 {
 	int node = dev_to_node(dev);
 	struct page *page = NULL;
@@ -106,9 +106,12 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
 	}
 
 	page = dma_alloc_contiguous(dev, size, gfp);
-	if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
-		dma_free_contiguous(dev, page, size);
-		page = NULL;
+	if (page) {
+		if (!dma_coherent_ok(dev, page_to_phys(page), size) ||
+		    (!allow_highmem && PageHighMem(page))) {
+			dma_free_contiguous(dev, page, size);
+			page = NULL;
+		}
 	}
 again:
 	if (!page)
@@ -154,7 +157,7 @@ static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size,
 {
 	struct page *page;
 
-	page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
+	page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true);
 	if (!page)
 		return NULL;
 
@@ -209,7 +212,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 
 	/* we always manually zero the memory once we are done */
-	page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
+	page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true);
 	if (!page)
 		return NULL;
 
@@ -335,19 +338,9 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 	    !is_swiotlb_for_alloc(dev))
 		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, false);
 	if (!page)
 		return NULL;
-	if (PageHighMem(page)) {
-		/*
-		 * Depending on the cma= arguments and per-arch setup
-		 * dma_alloc_contiguous could return highmem pages.
-		 * Without remapping there is no way to return them here,
-		 * so log an error and fail.
-		 */
-		dev_info(dev, "Rejecting highmem page from CMA.\n");
-		goto out_free_pages;
-	}
 
 	ret = page_address(page);
 	if (force_dma_unencrypted(dev)) {
-- 
2.35.1