[PATCH 5.15.y 07/10] dma-direct: add a dma_direct_use_pool helper

[Sasha Levin <sashal@kernel.org>]

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit 28e4576d556bca543b0996e9edd4b767397e24c6 ]

Add a helper to check if a potentially blocking operation should
dip into the atomic pools.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
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 | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 0f9b9a52b274c..97bd785560239 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -159,6 +159,15 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
 	return page;
 }
 
+/*
+ * Check if a potentially blocking operations needs to dip into the atomic
+ * pools for the given device/gfp.
+ */
+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)
 {
@@ -238,8 +247,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 		 */
 		remap = IS_ENABLED(CONFIG_DMA_DIRECT_REMAP);
 		if (remap) {
-			if (!gfpflags_allow_blocking(gfp) &&
-			    !is_swiotlb_for_alloc(dev))
+			if (dma_direct_use_pool(dev, gfp))
 				return dma_direct_alloc_from_pool(dev, size,
 						dma_handle, gfp);
 		} else {
@@ -253,8 +261,7 @@ void *dma_direct_alloc(struct device *dev, size_t size,
 	 * Decrypting memory may block, so allocate the memory from the atomic
 	 * pools if we can't block.
 	 */
-	if (force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp) &&
-	    !is_swiotlb_for_alloc(dev))
+	if (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 */
@@ -363,8 +370,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 	struct page *page;
 	void *ret;
 
-	if (force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp) &&
-	    !is_swiotlb_for_alloc(dev))
+	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, false);
-- 
2.53.0