On Thu, Jun 13, 2024 at 11:10:57PM +0530, Bibek Kumar Patro wrote:
>
>
> 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@xxxxxxxxxxxxxxx # v5.15+
> > > > Cc: Tom Murphy <murphyt7@xxxxxx>
> > > > Cc: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > > > Cc: Saravana Kannan <saravanak@xxxxxxxxxx>
> > > > Signed-off-by: Isaac J. Manjarres <isaacmanjarres@xxxxxxxxxx>
> > > > Link: https://lore.kernel.org/r/20231208234141.2356157-1-isaacmanjarres@xxxxxxxxxx
> > > > Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
> > > > (cherry picked from commit a63c357b9fd56ad5fe64616f5b22835252c6a76a)
> > > > Signed-off-by: Isaac J. Manjarres <isaacmanjarres@xxxxxxxxxx>
> > > > ---
> > > > 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 ?
Please backport what is in the tree already.
