[PATCH 5.17 361/772] dma-direct: dont fail on highmem CMA pages in dma_direct_alloc_pages

Greg Kroah-Hartman
2022-06-07T21:07:07Z

From: Christoph Hellwig <hch@lst.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@tumblingdice.co.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.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 50f48e9e4598..0be095579010 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -115,7 +115,7 @@ static struct page *dma_direct_alloc_swiotlb(struct device *dev, size_t size)
}

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;
@@ -129,9 +129,12 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
&phys_limit);
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)
@@ -189,7 +192,7 @@ 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;

@@ -262,7 +265,7 @@ 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;
if (PageHighMem(page)) {
@@ -370,19 +373,9 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, 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, 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 (dma_set_decrypted(dev, ret, size))
--
2.35.1