| Message ID | 20161025153703.4815.13673.stgit@ahduyck-blue-test.jf.intel.com |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Jeff Kirsher |
| Headers | show |
On Tue, Oct 25, 2016 at 11:37:03AM -0400, Alexander Duyck wrote: > As a first step to making DMA_ATTR_SKIP_CPU_SYNC apply to architectures > beyond just ARM I need to make it so that the swiotlb will respect the > flag. In order to do that I also need to update the swiotlb-xen since it > heavily makes use of the functionality. > > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> I am pretty sure I acked it the RFC. Was there a particular reason (this is very different from the RFC?) you dropped my ACk? Thanks. > Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> > --- > drivers/xen/swiotlb-xen.c | 11 +++++++--- > include/linux/swiotlb.h | 6 ++++-- > lib/swiotlb.c | 48 +++++++++++++++++++++++++++------------------ > 3 files changed, 40 insertions(+), 25 deletions(-) > > diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c > index b8014bf..3d048af 100644 > --- a/drivers/xen/swiotlb-xen.c > +++ b/drivers/xen/swiotlb-xen.c > @@ -405,7 +405,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, > */ > trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force); > > - map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir); > + map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir, > + attrs); > if (map == SWIOTLB_MAP_ERROR) > return DMA_ERROR_CODE; > > @@ -419,7 +420,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, > if (dma_capable(dev, dev_addr, size)) > return dev_addr; > > - swiotlb_tbl_unmap_single(dev, map, size, dir); > + swiotlb_tbl_unmap_single(dev, map, size, dir, > + attrs | DMA_ATTR_SKIP_CPU_SYNC); > > return DMA_ERROR_CODE; > } > @@ -445,7 +447,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr, > > /* NOTE: We use dev_addr here, not paddr! */ > if (is_xen_swiotlb_buffer(dev_addr)) { > - swiotlb_tbl_unmap_single(hwdev, paddr, size, dir); > + swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs); > return; > } > > @@ -558,11 +560,12 @@ void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, > start_dma_addr, > sg_phys(sg), > sg->length, > - dir); > + dir, attrs); > if (map == SWIOTLB_MAP_ERROR) { > dev_warn(hwdev, "swiotlb buffer is full\n"); > /* Don't panic here, we expect map_sg users > to do proper error handling. */ > + attrs |= DMA_ATTR_SKIP_CPU_SYNC; > xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, > attrs); > sg_dma_len(sgl) = 0; > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h > index e237b6f..4517be9 100644 > --- a/include/linux/swiotlb.h > +++ b/include/linux/swiotlb.h > @@ -44,11 +44,13 @@ enum dma_sync_target { > extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, > dma_addr_t tbl_dma_addr, > phys_addr_t phys, size_t size, > - enum dma_data_direction dir); > + enum dma_data_direction dir, > + unsigned long attrs); > > extern void swiotlb_tbl_unmap_single(struct device *hwdev, > phys_addr_t tlb_addr, > - size_t size, enum dma_data_direction dir); > + size_t size, enum dma_data_direction dir, > + unsigned long attrs); > > extern void swiotlb_tbl_sync_single(struct device *hwdev, > phys_addr_t tlb_addr, > diff --git a/lib/swiotlb.c b/lib/swiotlb.c > index 47aad37..b538d39 100644 > --- a/lib/swiotlb.c > +++ b/lib/swiotlb.c > @@ -425,7 +425,8 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr, > phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, > dma_addr_t tbl_dma_addr, > phys_addr_t orig_addr, size_t size, > - enum dma_data_direction dir) > + enum dma_data_direction dir, > + unsigned long attrs) > { > unsigned long flags; > phys_addr_t tlb_addr; > @@ -526,7 +527,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, > */ > for (i = 0; i < nslots; i++) > io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT); > - if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) > + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) && > + (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) > swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE); > > return tlb_addr; > @@ -539,18 +541,20 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, > > static phys_addr_t > map_single(struct device *hwdev, phys_addr_t phys, size_t size, > - enum dma_data_direction dir) > + enum dma_data_direction dir, unsigned long attrs) > { > dma_addr_t start_dma_addr = phys_to_dma(hwdev, io_tlb_start); > > - return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir); > + return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, > + dir, attrs); > } > > /* > * dma_addr is the kernel virtual address of the bounce buffer to unmap. > */ > void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, > - size_t size, enum dma_data_direction dir) > + size_t size, enum dma_data_direction dir, > + unsigned long attrs) > { > unsigned long flags; > int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; > @@ -561,6 +565,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, > * First, sync the memory before unmapping the entry > */ > if (orig_addr != INVALID_PHYS_ADDR && > + !(attrs & DMA_ATTR_SKIP_CPU_SYNC) && > ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))) > swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE); > > @@ -654,7 +659,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, > * GFP_DMA memory; fall back on map_single(), which > * will grab memory from the lowest available address range. > */ > - phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE); > + phys_addr_t paddr = map_single(hwdev, 0, size, > + DMA_FROM_DEVICE, 0); > if (paddr == SWIOTLB_MAP_ERROR) > goto err_warn; > > @@ -669,7 +675,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, > > /* DMA_TO_DEVICE to avoid memcpy in unmap_single */ > swiotlb_tbl_unmap_single(hwdev, paddr, > - size, DMA_TO_DEVICE); > + size, DMA_TO_DEVICE, > + DMA_ATTR_SKIP_CPU_SYNC); > goto err_warn; > } > } > @@ -699,7 +706,7 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, > free_pages((unsigned long)vaddr, get_order(size)); > else > /* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single */ > - swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE); > + swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE, 0); > } > EXPORT_SYMBOL(swiotlb_free_coherent); > > @@ -755,7 +762,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, > trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force); > > /* Oh well, have to allocate and map a bounce buffer. */ > - map = map_single(dev, phys, size, dir); > + map = map_single(dev, phys, size, dir, attrs); > if (map == SWIOTLB_MAP_ERROR) { > swiotlb_full(dev, size, dir, 1); > return phys_to_dma(dev, io_tlb_overflow_buffer); > @@ -764,12 +771,13 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, > dev_addr = phys_to_dma(dev, map); > > /* Ensure that the address returned is DMA'ble */ > - if (!dma_capable(dev, dev_addr, size)) { > - swiotlb_tbl_unmap_single(dev, map, size, dir); > - return phys_to_dma(dev, io_tlb_overflow_buffer); > - } > + if (dma_capable(dev, dev_addr, size)) > + return dev_addr; > + > + swiotlb_tbl_unmap_single(dev, map, size, dir, > + attrs | DMA_ATTR_SKIP_CPU_SYNC); > > - return dev_addr; > + return phys_to_dma(dev, io_tlb_overflow_buffer); > } > EXPORT_SYMBOL_GPL(swiotlb_map_page); > > @@ -782,14 +790,15 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, > * whatever the device wrote there. > */ > static void unmap_single(struct device *hwdev, dma_addr_t dev_addr, > - size_t size, enum dma_data_direction dir) > + size_t size, enum dma_data_direction dir, > + unsigned long attrs) > { > phys_addr_t paddr = dma_to_phys(hwdev, dev_addr); > > BUG_ON(dir == DMA_NONE); > > if (is_swiotlb_buffer(paddr)) { > - swiotlb_tbl_unmap_single(hwdev, paddr, size, dir); > + swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs); > return; > } > > @@ -809,7 +818,7 @@ void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, > size_t size, enum dma_data_direction dir, > unsigned long attrs) > { > - unmap_single(hwdev, dev_addr, size, dir); > + unmap_single(hwdev, dev_addr, size, dir, attrs); > } > EXPORT_SYMBOL_GPL(swiotlb_unmap_page); > > @@ -891,7 +900,7 @@ void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, > if (swiotlb_force || > !dma_capable(hwdev, dev_addr, sg->length)) { > phys_addr_t map = map_single(hwdev, sg_phys(sg), > - sg->length, dir); > + sg->length, dir, attrs); > if (map == SWIOTLB_MAP_ERROR) { > /* Don't panic here, we expect map_sg users > to do proper error handling. */ > @@ -925,7 +934,8 @@ void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, > BUG_ON(dir == DMA_NONE); > > for_each_sg(sgl, sg, nelems, i) > - unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir); > + unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, > + attrs); > > } > EXPORT_SYMBOL(swiotlb_unmap_sg_attrs); >
On Fri, Oct 28, 2016 at 10:34 AM, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote: > On Tue, Oct 25, 2016 at 11:37:03AM -0400, Alexander Duyck wrote: >> As a first step to making DMA_ATTR_SKIP_CPU_SYNC apply to architectures >> beyond just ARM I need to make it so that the swiotlb will respect the >> flag. In order to do that I also need to update the swiotlb-xen since it >> heavily makes use of the functionality. >> >> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > > I am pretty sure I acked it the RFC. Was there a particular > reason (this is very different from the RFC?) you dropped my ACk? > > Thanks. If I recall you had acked patch 1, but for 2 you had some review comments on and suggested I change a few things. What was patch 2 in the RFC was split out into patches 2 and 3. That is why I didn't include an Ack from you for those patches. Patch 2 is a fix for Xen to address the fact that you could return either 0 or ~0. It was part of patch 2 originally and I pulled it out into a separate patch. Patch 3 does most of what patch 2 in the RFC was doing before with fixes to address the fact that I was moving some code to avoid going over 80 characters. I found a different way to fix that by just updating attrs before using it instead of ORing in the value when passing it as a parameter. >> @@ -558,11 +560,12 @@ void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, >> start_dma_addr, >> sg_phys(sg), >> sg->length, >> - dir); >> + dir, attrs); >> if (map == SWIOTLB_MAP_ERROR) { >> dev_warn(hwdev, "swiotlb buffer is full\n"); >> /* Don't panic here, we expect map_sg users >> to do proper error handling. */ >> + attrs |= DMA_ATTR_SKIP_CPU_SYNC; >> xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, >> attrs); >> sg_dma_len(sgl) = 0; The biggest difference from patch 2 in the RFC is right here. This code before was moving this off to the end of the function and adding a label which I then jumped to. I just ORed the DMA_ATTR_SKIP_CPU_SYNC into attrs and skipped the problem entirely. It should be harmless to do this way since attrs isn't used anywhere else once we have had the error. I hope that helps to clear it up. So if you want I will add your Acked-by for patches 2 and 3, but I just wanted to make sure this worked with the changes you suggested. Thanks. - Alex
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index b8014bf..3d048af 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -405,7 +405,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, */ trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force); - map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir); + map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir, + attrs); if (map == SWIOTLB_MAP_ERROR) return DMA_ERROR_CODE; @@ -419,7 +420,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, if (dma_capable(dev, dev_addr, size)) return dev_addr; - swiotlb_tbl_unmap_single(dev, map, size, dir); + swiotlb_tbl_unmap_single(dev, map, size, dir, + attrs | DMA_ATTR_SKIP_CPU_SYNC); return DMA_ERROR_CODE; } @@ -445,7 +447,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr, /* NOTE: We use dev_addr here, not paddr! */ if (is_xen_swiotlb_buffer(dev_addr)) { - swiotlb_tbl_unmap_single(hwdev, paddr, size, dir); + swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs); return; } @@ -558,11 +560,12 @@ void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, start_dma_addr, sg_phys(sg), sg->length, - dir); + dir, attrs); if (map == SWIOTLB_MAP_ERROR) { dev_warn(hwdev, "swiotlb buffer is full\n"); /* Don't panic here, we expect map_sg users to do proper error handling. */ + attrs |= DMA_ATTR_SKIP_CPU_SYNC; xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, attrs); sg_dma_len(sgl) = 0; diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index e237b6f..4517be9 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -44,11 +44,13 @@ enum dma_sync_target { extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, dma_addr_t tbl_dma_addr, phys_addr_t phys, size_t size, - enum dma_data_direction dir); + enum dma_data_direction dir, + unsigned long attrs); extern void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, - size_t size, enum dma_data_direction dir); + size_t size, enum dma_data_direction dir, + unsigned long attrs); extern void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, diff --git a/lib/swiotlb.c b/lib/swiotlb.c index 47aad37..b538d39 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -425,7 +425,8 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr, phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, dma_addr_t tbl_dma_addr, phys_addr_t orig_addr, size_t size, - enum dma_data_direction dir) + enum dma_data_direction dir, + unsigned long attrs) { unsigned long flags; phys_addr_t tlb_addr; @@ -526,7 +527,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, */ for (i = 0; i < nslots; i++) io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT); - if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) && + (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE); return tlb_addr; @@ -539,18 +541,20 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, static phys_addr_t map_single(struct device *hwdev, phys_addr_t phys, size_t size, - enum dma_data_direction dir) + enum dma_data_direction dir, unsigned long attrs) { dma_addr_t start_dma_addr = phys_to_dma(hwdev, io_tlb_start); - return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir); + return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, + dir, attrs); } /* * dma_addr is the kernel virtual address of the bounce buffer to unmap. */ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, - size_t size, enum dma_data_direction dir) + size_t size, enum dma_data_direction dir, + unsigned long attrs) { unsigned long flags; int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; @@ -561,6 +565,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, * First, sync the memory before unmapping the entry */ if (orig_addr != INVALID_PHYS_ADDR && + !(attrs & DMA_ATTR_SKIP_CPU_SYNC) && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))) swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE); @@ -654,7 +659,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, * GFP_DMA memory; fall back on map_single(), which * will grab memory from the lowest available address range. */ - phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE); + phys_addr_t paddr = map_single(hwdev, 0, size, + DMA_FROM_DEVICE, 0); if (paddr == SWIOTLB_MAP_ERROR) goto err_warn; @@ -669,7 +675,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, /* DMA_TO_DEVICE to avoid memcpy in unmap_single */ swiotlb_tbl_unmap_single(hwdev, paddr, - size, DMA_TO_DEVICE); + size, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); goto err_warn; } } @@ -699,7 +706,7 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, free_pages((unsigned long)vaddr, get_order(size)); else /* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single */ - swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE); + swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE, 0); } EXPORT_SYMBOL(swiotlb_free_coherent); @@ -755,7 +762,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force); /* Oh well, have to allocate and map a bounce buffer. */ - map = map_single(dev, phys, size, dir); + map = map_single(dev, phys, size, dir, attrs); if (map == SWIOTLB_MAP_ERROR) { swiotlb_full(dev, size, dir, 1); return phys_to_dma(dev, io_tlb_overflow_buffer); @@ -764,12 +771,13 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, dev_addr = phys_to_dma(dev, map); /* Ensure that the address returned is DMA'ble */ - if (!dma_capable(dev, dev_addr, size)) { - swiotlb_tbl_unmap_single(dev, map, size, dir); - return phys_to_dma(dev, io_tlb_overflow_buffer); - } + if (dma_capable(dev, dev_addr, size)) + return dev_addr; + + swiotlb_tbl_unmap_single(dev, map, size, dir, + attrs | DMA_ATTR_SKIP_CPU_SYNC); - return dev_addr; + return phys_to_dma(dev, io_tlb_overflow_buffer); } EXPORT_SYMBOL_GPL(swiotlb_map_page); @@ -782,14 +790,15 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, * whatever the device wrote there. */ static void unmap_single(struct device *hwdev, dma_addr_t dev_addr, - size_t size, enum dma_data_direction dir) + size_t size, enum dma_data_direction dir, + unsigned long attrs) { phys_addr_t paddr = dma_to_phys(hwdev, dev_addr); BUG_ON(dir == DMA_NONE); if (is_swiotlb_buffer(paddr)) { - swiotlb_tbl_unmap_single(hwdev, paddr, size, dir); + swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs); return; } @@ -809,7 +818,7 @@ void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, size_t size, enum dma_data_direction dir, unsigned long attrs) { - unmap_single(hwdev, dev_addr, size, dir); + unmap_single(hwdev, dev_addr, size, dir, attrs); } EXPORT_SYMBOL_GPL(swiotlb_unmap_page); @@ -891,7 +900,7 @@ void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, if (swiotlb_force || !dma_capable(hwdev, dev_addr, sg->length)) { phys_addr_t map = map_single(hwdev, sg_phys(sg), - sg->length, dir); + sg->length, dir, attrs); if (map == SWIOTLB_MAP_ERROR) { /* Don't panic here, we expect map_sg users to do proper error handling. */ @@ -925,7 +934,8 @@ void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, BUG_ON(dir == DMA_NONE); for_each_sg(sgl, sg, nelems, i) - unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir); + unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, + attrs); } EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
As a first step to making DMA_ATTR_SKIP_CPU_SYNC apply to architectures beyond just ARM I need to make it so that the swiotlb will respect the flag. In order to do that I also need to update the swiotlb-xen since it heavily makes use of the functionality. Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> --- drivers/xen/swiotlb-xen.c | 11 +++++++--- include/linux/swiotlb.h | 6 ++++-- lib/swiotlb.c | 48 +++++++++++++++++++++++++++------------------ 3 files changed, 40 insertions(+), 25 deletions(-)