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Date:   Fri,  8 Dec 2023 15:41:40 -0800
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Message-ID: <20231208234141.2356157-1-isaacmanjarres@google.com>
Subject: [PATCH v1] iommu/dma: Trace bounce buffer usage when mapping buffers
From:   "Isaac J. Manjarres" <isaacmanjarres@google.com>
To:     Robin Murphy <robin.murphy@arm.com>,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Tom Murphy <murphyt7@tcd.ie>,
        Lu Baolu <baolu.lu@linux.intel.com>
Cc:     "Isaac J. Manjarres" <isaacmanjarres@google.com>,
        stable@vger.kernel.org, Saravana Kannan <saravanak@google.com>,
        kernel-team@android.com, iommu@lists.linux.dev,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

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>
---
 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 85163a83df2f..037fcf826407 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -29,6 +29,7 @@
 #include <linux/spinlock.h>
 #include <linux/swiotlb.h>
 #include <linux/vmalloc.h>
+#include <trace/events/swiotlb.h>
 
 #include "dma-iommu.h"
 
@@ -1156,6 +1157,8 @@ static dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
 			return DMA_MAPPING_ERROR;
 		}
 
+		trace_swiotlb_bounced(dev, phys, size);
+
 		aligned_size = iova_align(iovad, size);
 		phys = swiotlb_tbl_map_single(dev, phys, size, aligned_size,
 					      iova_mask(iovad), dir, attrs);
-- 
2.43.0.472.g3155946c3a-goog