Attachment 312462 Details for Bug 298811 – Upstream patch that fixes this issue

[patch] Upstream patch that fixes this issue

upstream2.patch (text/plain), 4.91 KB, created by Prarit Bhargava on 2008-07-23 11:22:12 UTC

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Creator: Prarit Bhargava

Created: 2008-07-23 11:22:12 UTC

Size: 4.91 KB

patch

obsolete

>pci_alloc_consistent/dma_alloc_coherent does not return size aligned
>addresses.
>
>From Documentation/DMA-mapping.txt:
>
>"pci_alloc_consistent returns two values: the virtual address which you
>can use to access it from the CPU and dma_handle which you pass to the
>card.
>
>The cpu return address and the DMA bus master address are both
>guaranteed to be aligned to the smallest PAGE_SIZE order which
>is greater than or equal to the requested size.  This invariant
>exists (for example) to guarantee that if you allocate a chunk
>which is smaller than or equal to 64 kilobytes, the extent of the
>buffer you receive will not cross a 64K boundary."
>
>1.  Modify alloc_iommu to allow for an alignment mask
>2.  Modify pci_gart_simple to return size-aligned values.
>3.  Fixup the alignment calculation in the iommu-helper code.
>4.  Fix possible overflow in alloc_iommu's boundary_size calculation.
>    (It is possible that alloc_iommu()'s boundary_size overflows as
>     dma_get_seg_boundary can return 0xffffffff.  In that case, further usage of
>     boundary_size triggers a BUG_ON() in the iommu code.)
>
>End result: When allocating from IOMMU, pci_alloc_consistent/dma_alloc_coherent
>will now return a size aligned value.
>
>Signed-off-by: Prarit Bhargava <prarit@redhat.com>
>
>diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
>index faf3229..717ae64 100644
>--- a/arch/x86/kernel/pci-gart_64.c
>+++ b/arch/x86/kernel/pci-gart_64.c
>@@ -83,7 +83,8 @@ AGPEXTERN __u32 *agp_gatt_table;
> static unsigned long next_bit;  /* protected by iommu_bitmap_lock */
> static int need_flush;		/* global flush state. set for each gart wrap */
> 
>-static unsigned long alloc_iommu(struct device *dev, int size)
>+static unsigned long alloc_iommu(struct device *dev, int size,
>+				 unsigned long mask)
> {
> 	unsigned long offset, flags;
> 	unsigned long boundary_size;
>@@ -91,16 +92,17 @@ static unsigned long alloc_iommu(struct device *dev, int size)
> 
> 	base_index = ALIGN(iommu_bus_base & dma_get_seg_boundary(dev),
> 			   PAGE_SIZE) >> PAGE_SHIFT;
>-	boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
>+	boundary_size = ALIGN((unsigned long long)dma_get_seg_boundary(dev) + 1,
> 			      PAGE_SIZE) >> PAGE_SHIFT;
> 
> 	spin_lock_irqsave(&iommu_bitmap_lock, flags);
> 	offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, next_bit,
>-				  size, base_index, boundary_size, 0);
>+				  size, base_index, boundary_size, mask);
> 	if (offset == -1) {
> 		need_flush = 1;
> 		offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, 0,
>-					  size, base_index, boundary_size, 0);
>+					  size, base_index, boundary_size,
>+					  mask);
> 	}
> 	if (offset != -1) {
> 		set_bit_string(iommu_gart_bitmap, offset, size);
>@@ -240,10 +242,11 @@ nonforced_iommu(struct device *dev, unsigned long addr, size_t size)
>  * Caller needs to check if the iommu is needed and flush.
>  */
> static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
>-				size_t size, int dir)
>+				size_t size, int dir, u64 align_mask)
> {
> 	unsigned long npages = to_pages(phys_mem, size);
>-	unsigned long iommu_page = alloc_iommu(dev, npages);
>+	unsigned long palign_mask = align_mask >> PAGE_SHIFT;
>+	unsigned long iommu_page = alloc_iommu(dev, npages, palign_mask);
> 	int i;
> 
> 	if (iommu_page == -1) {
>@@ -266,7 +269,8 @@ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
> static dma_addr_t
> gart_map_simple(struct device *dev, char *buf, size_t size, int dir)
> {
>-	dma_addr_t map = dma_map_area(dev, virt_to_bus(buf), size, dir);
>+	dma_addr_t map = dma_map_area(dev, virt_to_bus(buf), size, dir,
>+				      size - 1);
> 
> 	flush_gart();
> 
>@@ -286,7 +290,8 @@ gart_map_single(struct device *dev, void *addr, size_t size, int dir)
> 	if (!need_iommu(dev, phys_mem, size))
> 		return phys_mem;
> 
>-	bus = gart_map_simple(dev, addr, size, dir);
>+	dma_addr_t map = dma_map_area(dev, virt_to_bus(addr), size, dir, 0);
>+	flush_gart();
> 
> 	return bus;
> }
>@@ -345,7 +350,7 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
> 		unsigned long addr = sg_phys(s);
> 
> 		if (nonforced_iommu(dev, addr, s->length)) {
>-			addr = dma_map_area(dev, addr, s->length, dir);
>+			addr = dma_map_area(dev, addr, s->length, dir, 0);
> 			if (addr == bad_dma_address) {
> 				if (i > 0)
> 					gart_unmap_sg(dev, sg, i, dir);
>@@ -367,7 +372,7 @@ static int __dma_map_cont(struct device *dev, struct scatterlist *start,
> 			  int nelems, struct scatterlist *sout,
> 			  unsigned long pages)
> {
>-	unsigned long iommu_start = alloc_iommu(dev, pages);
>+	unsigned long iommu_start = alloc_iommu(dev, pages, 0);
> 	unsigned long iommu_page = iommu_start;
> 	struct scatterlist *s;
> 	int i;
>diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c
>index a3b8d4c..39940e7 100644
>--- a/lib/iommu-helper.c
>+++ b/lib/iommu-helper.c
>@@ -16,7 +16,7 @@ again:
> 	index = find_next_zero_bit(map, size, start);
> 
> 	/* Align allocation */
>-	index = (index + align_mask) & ~align_mask;
>+	index = __ALIGN_MASK(index, align_mask);
> 
> 	end = index + nr;
> 	if (end >= size)

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Attachments on bug 298811: 216601 | 217641 | 217701 | 217711 | 246651 | 296071 | 296072 | 302376 | 310803 | 310807 | 310860 | 312159 | 312162 | 312163 | 312462 | 312916