On 6/13/2024 4:45 PM, Greg KH wrote:
On Thu, Jun 13, 2024 at 04:01:01PM +0530, Bibek Kumar Patro wrote:
On Mon, Jan 22, 2024 at 12:37:54PM -0800, Isaac J. Manjarres wrote:
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);Hi, this backported patch trying to access swiotlb_force variable is causing a build conflict where CONFIG_SWIOTLB is not enabled.
In file included from kernel/drivers/iommu/dma-iommu.c:28: kernel/include/trace/events/swiotlb.h:15:9: error: declaration of 'enum SWIOTLB_NO_FORCE' will not be visible outside of this function [-Werror,-Wvisibility] enum swiotlb_force swiotlb_force), ^ kernel/include/linux/swiotlb.h:143:23: note: expanded from macro 'swiotlb_force' #define swiotlb_force SWIOTLB_NO_FORCE ^ In file included from kernel/drivers/iommu/dma-iommu.c:28: kernel/include/trace/events/swiotlb.h:15:9: error: declaration of 'enum SWIOTLB_NO_FORCE' will not be visible outside of this function [-Werror,-Wvisibility] kernel/include/linux/swiotlb.h:143:23: note: expanded from macro 'swiotlb_force' #define swiotlb_force SWIOTLB_NO_FORCE ^ In file included from kernel/drivers/iommu/dma-iommu.c:28: kernel/include/trace/events/swiotlb.h:15:9: error: declaration of 'enum SWIOTLB_NO_FORCE' will not be visible outside of this function [-Werror,-Wvisibility] kernel/include/linux/swiotlb.h:143:23: note: expanded from macro 'swiotlb_force' #define swiotlb_force SWIOTLB_NO_FORCE ^ In file included from kernel/drivers/iommu/dma-iommu.c:28: kernel/include/trace/events/swiotlb.h:15:9: error: declaration of 'enum SWIOTLB_NO_FORCE' will not be visible outside of this function [-Werror,-Wvisibility] kernel/include/linux/swiotlb.h:143:23: note: expanded from macro 'swiotlb_force' #define swiotlb_force SWIOTLB_NO_FORCE ^ kernel/drivers/iommu/dma-iommu.c:865:42: error: argument type 'enum SWIOTLB_NO_FORCE' is incomplete trace_swiotlb_bounced(dev, phys, size, swiotlb_force); ^~~~~~~~~~~~~ kernel/include/linux/swiotlb.h:143:23: note: expanded from macro 'swiotlb_force' #define swiotlb_force SWIOTLB_NO_FORCE ^~~~~~~~~~~~~~~~ kernel/include/trace/events/swiotlb.h:15:9: note: forward declaration of 'enum SWIOTLB_NO_FORCE' enum swiotlb_force swiotlb_force), ^ kernel/include/linux/swiotlb.h:143:23: note: expanded from macro 'swiotlb_force' #define swiotlb_force SWIOTLB_NO_FORCE
I have a simple proposed fix which can resolve this compile time conflict when CONFIG_SWIOTLB is disabled.
--- a/include/trace/events/swiotlb.h +++ b/include/trace/events/swiotlb.h @@ -7,6 +7,7 @@
#include <linux/tracepoint.h>
+#ifdef CONFIG_SWIOTLB TRACE_EVENT(swiotlb_bounced,
TP_PROTO(struct device *dev,@@ -43,6 +44,9 @@ TRACE_EVENT(swiotlb_bounced, { SWIOTLB_FORCE, "FORCE" }, { SWIOTLB_NO_FORCE, "NO_FORCE" })) ); +#else +#define trace_swiotlb_bounced(dev, phys, size, swiotlb_force) +#endif /* CONFIG_SWIOTLB */
#endif /* _TRACE_SWIOTLB_H */
Why not just take whatever change upstream fixes this instead of a one-off change?
I am currently checking the history on swiotlb_force and how it's removed in latest kernel versions. If those changes are applicable on this stable branch can we explore backporting those instead of this one- off change ?
Thanks & regards, Bibek
thanks
greg k-h