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authorNicolin Chen <nicoleotsuka@gmail.com>2020-09-02 01:16:45 +0300
committerChristoph Hellwig <hch@lst.de>2020-09-03 19:12:15 +0300
commit1e9d90dbed120ec98517428ffff4dacd9797e39d (patch)
treed743be6b54427bb62e36e6d1ae2f6fc243cd70b7 /arch/sparc
parent2281f797f5524abb8fff66bf8540b4f4687332a2 (diff)
downloadlinux-1e9d90dbed120ec98517428ffff4dacd9797e39d.tar.xz
dma-mapping: introduce dma_get_seg_boundary_nr_pages()
We found that callers of dma_get_seg_boundary mostly do an ALIGN with page mask and then do a page shift to get number of pages: ALIGN(boundary + 1, 1 << shift) >> shift However, the boundary might be as large as ULONG_MAX, which means that a device has no specific boundary limit. So either "+ 1" or passing it to ALIGN() would potentially overflow. According to kernel defines: #define ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask)) #define ALIGN(x, a) ALIGN_MASK(x, (typeof(x))(a) - 1) We can simplify the logic here into a helper function doing: ALIGN(boundary + 1, 1 << shift) >> shift = ALIGN_MASK(b + 1, (1 << s) - 1) >> s = {[b + 1 + (1 << s) - 1] & ~[(1 << s) - 1]} >> s = [b + 1 + (1 << s) - 1] >> s = [b + (1 << s)] >> s = (b >> s) + 1 This patch introduces and applies dma_get_seg_boundary_nr_pages() as an overflow-free helper for the dma_get_seg_boundary() callers to get numbers of pages. It also takes care of the NULL dev case for non-DMA API callers. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com> Acked-by: Niklas Schnelle <schnelle@linux.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'arch/sparc')
-rw-r--r--arch/sparc/kernel/iommu-common.c10
-rw-r--r--arch/sparc/kernel/iommu.c3
-rw-r--r--arch/sparc/kernel/pci_sun4v.c3
3 files changed, 5 insertions, 11 deletions
diff --git a/arch/sparc/kernel/iommu-common.c b/arch/sparc/kernel/iommu-common.c
index 59cb16691322..23ca75f09277 100644
--- a/arch/sparc/kernel/iommu-common.c
+++ b/arch/sparc/kernel/iommu-common.c
@@ -166,13 +166,6 @@ unsigned long iommu_tbl_range_alloc(struct device *dev,
}
}
- if (dev)
- boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
- 1 << iommu->table_shift);
- else
- boundary_size = ALIGN(1ULL << 32, 1 << iommu->table_shift);
-
- boundary_size = boundary_size >> iommu->table_shift;
/*
* if the skip_span_boundary_check had been set during init, we set
* things up so that iommu_is_span_boundary() merely checks if the
@@ -181,6 +174,9 @@ unsigned long iommu_tbl_range_alloc(struct device *dev,
if ((iommu->flags & IOMMU_NO_SPAN_BOUND) != 0) {
shift = 0;
boundary_size = iommu->poolsize * iommu->nr_pools;
+ } else {
+ boundary_size = dma_get_seg_boundary_nr_pages(dev,
+ iommu->table_shift);
}
n = iommu_area_alloc(iommu->map, limit, start, npages, shift,
boundary_size, align_mask);
diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
index 4ae7388b1bff..c3e4e2df26a8 100644
--- a/arch/sparc/kernel/iommu.c
+++ b/arch/sparc/kernel/iommu.c
@@ -472,8 +472,7 @@ static int dma_4u_map_sg(struct device *dev, struct scatterlist *sglist,
outs->dma_length = 0;
max_seg_size = dma_get_max_seg_size(dev);
- seg_boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
- IO_PAGE_SIZE) >> IO_PAGE_SHIFT;
+ seg_boundary_size = dma_get_seg_boundary_nr_pages(dev, IO_PAGE_SHIFT);
base_shift = iommu->tbl.table_map_base >> IO_PAGE_SHIFT;
for_each_sg(sglist, s, nelems, i) {
unsigned long paddr, npages, entry, out_entry = 0, slen;
diff --git a/arch/sparc/kernel/pci_sun4v.c b/arch/sparc/kernel/pci_sun4v.c
index 14b93c5564e3..6b92dd51c002 100644
--- a/arch/sparc/kernel/pci_sun4v.c
+++ b/arch/sparc/kernel/pci_sun4v.c
@@ -508,8 +508,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
iommu_batch_start(dev, prot, ~0UL);
max_seg_size = dma_get_max_seg_size(dev);
- seg_boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
- IO_PAGE_SIZE) >> IO_PAGE_SHIFT;
+ seg_boundary_size = dma_get_seg_boundary_nr_pages(dev, IO_PAGE_SHIFT);
mask = *dev->dma_mask;
if (!iommu_use_atu(iommu, mask))