FAILED: patch "[PATCH] dma-direct: return struct page from" failed to apply to 6.1-stable tree

FAILED: patch "[PATCH] dma-direct: return struct page from" failed to apply to 6.1-stable tree

[gregkh]

The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 94a04ad732c9f8b9554270fc4038a06737de5c22
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026090811-upwind-reseller-c91c@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 94a04ad732c9f8b9554270fc4038a06737de5c22 Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>
Date: Fri, 17 Jul 2026 23:34:19 +0530
Subject: [PATCH] dma-direct: return struct page from
 dma_direct_alloc_from_pool()

Commit 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool
helper") changed dma_direct_alloc_from_pool() to return the CPU address
from dma_alloc_from_pool(). That fits dma_direct_alloc(), but
dma_direct_alloc_pages() also uses the helper and expects a struct page *.

Fix this by making dma_direct_alloc_from_pool() return the struct page *
again, and pass the CPU address back through an out-parameter for the
dma_direct_alloc() caller.

Fixes: 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool helper")
Cc: stable@vger.kernel.org
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
Reviewed-by: Mostafa Saleh <smostafa@google.com>
Link: https://lore.kernel.org/r/20260717180442.110954-2-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 4391b797d4db..b4cb2c03e5d7 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -164,22 +164,21 @@ static bool dma_direct_use_pool(struct device *dev, gfp_t gfp)
 	return !gfpflags_allow_blocking(gfp) && !is_swiotlb_for_alloc(dev);
 }
 
-static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
-		dma_addr_t *dma_handle, gfp_t gfp)
+static struct page *dma_direct_alloc_from_pool(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, void **cpu_addr, gfp_t gfp)
 {
 	struct page *page;
 	u64 phys_limit;
-	void *ret;
 
 	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_DMA_COHERENT_POOL)))
 		return NULL;
 
 	gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit);
-	page = dma_alloc_from_pool(dev, size, &ret, gfp, dma_coherent_ok);
+	page = dma_alloc_from_pool(dev, size, cpu_addr, gfp, dma_coherent_ok);
 	if (!page)
 		return NULL;
 	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
-	return ret;
+	return page;
 }
 
 static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size,
@@ -247,8 +246,11 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 	 * the atomic pools instead if we aren't allowed block.
 	 */
 	if ((remap || force_dma_unencrypted(dev)) &&
-	    dma_direct_use_pool(dev, gfp))
-		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+	    dma_direct_use_pool(dev, gfp)) {
+		page = dma_direct_alloc_from_pool(dev, size, dma_handle,
+						  &ret, gfp);
+		return page ? ret : NULL;
+	}
 
 	/* we always manually zero the memory once we are done */
 	page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true);
@@ -357,7 +359,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 	void *ret;
 
 	if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
-		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+		return dma_direct_alloc_from_pool(dev, size, dma_handle, &ret, gfp);
 
 	page = __dma_direct_alloc_pages(dev, size, gfp, false);
 	if (!page)

[PATCH 6.1.y 1/3] dma-direct: cleanup parameters to dma_direct_optimal_gfp_mask

[Sasha Levin]

From: Petr Tesarik <petrtesarik@huaweicloud.com>

[ Upstream commit 25a4ce564921db0973b74c04e0ea23bd2ee12a3a ]

Since both callers of dma_direct_optimal_gfp_mask() pass
dev->coherent_dma_mask as the second argument, it is better to
remove that parameter altogether.

Not only is reducing number of parameters good for readability, but
the new function signature is also more logical: The optimal flags
depend only on data contained in struct device.

While touching this code, let's also rename phys_mask to phys_limit
in dma_direct_alloc_from_pool(), because it is indeed a limit.

Signed-off-by: Petr Tesarik <petrtesarik@huaweicloud.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Stable-dep-of: 94a04ad732c9 ("dma-direct: return struct page from dma_direct_alloc_from_pool()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/dma/direct.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index d4215739efc71..d6871a3fe5f6a 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -44,10 +44,11 @@ u64 dma_direct_get_required_mask(struct device *dev)
 	return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
 }
 
-static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
-				  u64 *phys_limit)
+static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 *phys_limit)
 {
-	u64 dma_limit = min_not_zero(dma_mask, dev->bus_dma_limit);
+	u64 dma_limit = min_not_zero(
+		dev->coherent_dma_mask,
+		dev->bus_dma_limit);
 
 	/*
 	 * Optimistically try the zone that the physical address mask falls
@@ -126,8 +127,7 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
 	if (is_swiotlb_for_alloc(dev))
 		return dma_direct_alloc_swiotlb(dev, size);
 
-	gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
-					   &phys_limit);
+	gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit);
 	page = dma_alloc_contiguous(dev, size, gfp);
 	if (page) {
 		if (!dma_coherent_ok(dev, page_to_phys(page), size) ||
@@ -172,14 +172,13 @@ static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, gfp_t gfp)
 {
 	struct page *page;
-	u64 phys_mask;
+	u64 phys_limit;
 	void *ret;
 
 	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_DMA_COHERENT_POOL)))
 		return NULL;
 
-	gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
-					   &phys_mask);
+	gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit);
 	page = dma_alloc_from_pool(dev, size, &ret, gfp, dma_coherent_ok);
 	if (!page)
 		return NULL;
-- 
2.53.0

[PATCH 6.1.y 2/3] dma-direct: simplify the use atomic pool logic in dma_direct_alloc

[Sasha Levin]

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit b1da46d70e5427a9ba5eae28bcca29a20e68a442 ]

The logic in dma_direct_alloc when to use the atomic pool vs remapping
grew a bit unreadable.  Consolidate it into a single check, and clean
up the set_uncached vs remap logic a bit as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
Stable-dep-of: 94a04ad732c9 ("dma-direct: return struct page from dma_direct_alloc_from_pool()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/dma/direct.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index d6871a3fe5f6a..621a711224574 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -240,27 +240,22 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 					dma_handle);
 
 		/*
-		 * Otherwise remap if the architecture is asking for it.  But
-		 * given that remapping memory is a blocking operation we'll
-		 * instead have to dip into the atomic pools.
+		 * Otherwise we require the architecture to either be able to
+		 * mark arbitrary parts of the kernel direct mapping uncached,
+		 * or remapped it uncached.
 		 */
+		set_uncached = IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED);
 		remap = IS_ENABLED(CONFIG_DMA_DIRECT_REMAP);
-		if (remap) {
-			if (dma_direct_use_pool(dev, gfp))
-				return dma_direct_alloc_from_pool(dev, size,
-						dma_handle, gfp);
-		} else {
-			if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED))
-				return NULL;
-			set_uncached = true;
-		}
+		if (!set_uncached && !remap)
+			return NULL;
 	}
 
 	/*
-	 * Decrypting memory may block, so allocate the memory from the atomic
-	 * pools if we can't block.
+	 * Remapping or decrypting memory may block, allocate the memory from
+	 * the atomic pools instead if we aren't allowed block.
 	 */
-	if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
+	if ((remap || force_dma_unencrypted(dev)) &&
+	    dma_direct_use_pool(dev, gfp))
 		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 
 	/* we always manually zero the memory once we are done */
-- 
2.53.0

[PATCH 6.1.y 3/3] dma-direct: return struct page from dma_direct_alloc_from_pool()

[Sasha Levin]

From: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>

[ Upstream commit 94a04ad732c9f8b9554270fc4038a06737de5c22 ]

Commit 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool
helper") changed dma_direct_alloc_from_pool() to return the CPU address
from dma_alloc_from_pool(). That fits dma_direct_alloc(), but
dma_direct_alloc_pages() also uses the helper and expects a struct page *.

Fix this by making dma_direct_alloc_from_pool() return the struct page *
again, and pass the CPU address back through an out-parameter for the
dma_direct_alloc() caller.

Fixes: 5b138c534fda ("dma-direct: factor out a dma_direct_alloc_from_pool helper")
Cc: stable@vger.kernel.org
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
Reviewed-by: Mostafa Saleh <smostafa@google.com>
Link: https://lore.kernel.org/r/20260717180442.110954-2-aneesh.kumar@kernel.org
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/dma/direct.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 621a711224574..88ec1b5cb5060 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -168,22 +168,21 @@ static bool dma_direct_use_pool(struct device *dev, gfp_t gfp)
 	return !gfpflags_allow_blocking(gfp) && !is_swiotlb_for_alloc(dev);
 }
 
-static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
-		dma_addr_t *dma_handle, gfp_t gfp)
+static struct page *dma_direct_alloc_from_pool(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, void **cpu_addr, gfp_t gfp)
 {
 	struct page *page;
 	u64 phys_limit;
-	void *ret;
 
 	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_DMA_COHERENT_POOL)))
 		return NULL;
 
 	gfp |= dma_direct_optimal_gfp_mask(dev, &phys_limit);
-	page = dma_alloc_from_pool(dev, size, &ret, gfp, dma_coherent_ok);
+	page = dma_alloc_from_pool(dev, size, cpu_addr, gfp, dma_coherent_ok);
 	if (!page)
 		return NULL;
 	*dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
-	return ret;
+	return page;
 }
 
 static void *dma_direct_alloc_no_mapping(struct device *dev, size_t size,
@@ -255,8 +254,11 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 	 * the atomic pools instead if we aren't allowed block.
 	 */
 	if ((remap || force_dma_unencrypted(dev)) &&
-	    dma_direct_use_pool(dev, gfp))
-		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+	    dma_direct_use_pool(dev, gfp)) {
+		page = dma_direct_alloc_from_pool(dev, size, dma_handle,
+						  &ret, gfp);
+		return page ? ret : NULL;
+	}
 
 	/* we always manually zero the memory once we are done */
 	page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO, true);
@@ -367,7 +369,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 	void *ret;
 
 	if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
-		return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
+		return dma_direct_alloc_from_pool(dev, size, dma_handle, &ret, gfp);
 
 	page = __dma_direct_alloc_pages(dev, size, gfp, false);
 	if (!page)
-- 
2.53.0