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Date: Mon, 22 Jan 2024 12:37:54 -0800
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Message-ID: <20240122203758.1435127-1-isaacmanjarres@google.com>
Subject: [PATCH 5.15.y] iommu/dma: Trace bounce buffer usage when mapping buffers
From: "Isaac J. Manjarres" <isaacmanjarres@google.com>
To: stable@vger.kernel.org, Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>, 
	Lu Baolu <baolu.lu@linux.intel.com>, Tom Murphy <murphyt7@tcd.ie>
Cc: "Isaac J. Manjarres" <isaacmanjarres@google.com>, Saravana Kannan <saravanak@google.com>, 
	Joerg Roedel <jroedel@suse.de>, kernel-team@android.com, iommu@lists.linux-foundation.org, 
	iommu@lists.linux.dev, linux-kernel@vger.kernel.org
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When commit 82612d66d51d ("iommu: Allow the dma-iommu api to
use bounce buffers") was introduced, it did not add the logic
for tracing the bounce buffer usage from iommu_dma_map_page().

All of the users of swiotlb_tbl_map_single() trace their bounce
buffer usage, except iommu_dma_map_page(). This makes it difficult
to track SWIOTLB usage from that function. Thus, trace bounce buffer
usage from iommu_dma_map_page().

Fixes: 82612d66d51d ("iommu: Allow the dma-iommu api to use bounce buffers")
Cc: stable@vger.kernel.org # v5.15+
Cc: Tom Murphy <murphyt7@tcd.ie>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com>
Link: https://lore.kernel.org/r/20231208234141.2356157-1-isaacmanjarres@google.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
(cherry picked from commit a63c357b9fd56ad5fe64616f5b22835252c6a76a)
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com>
---
 drivers/iommu/dma-iommu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 48c6f7ff4aef..8cd63e6ccd2c 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -25,6 +25,7 @@
 #include <linux/vmalloc.h>
 #include <linux/crash_dump.h>
 #include <linux/dma-direct.h>
+#include <trace/events/swiotlb.h>
 
 struct iommu_dma_msi_page {
 	struct list_head	list;
@@ -817,6 +818,8 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
 		void *padding_start;
 		size_t padding_size, aligned_size;
 
+		trace_swiotlb_bounced(dev, phys, size, swiotlb_force);
+
 		aligned_size = iova_align(iovad, size);
 		phys = swiotlb_tbl_map_single(dev, phys, size, aligned_size,
 					      iova_mask(iovad), dir, attrs);
-- 
2.43.0.429.g432eaa2c6b-goog