iommu sg merging: swiotlb: respect the segment boundary limits
This patch makes swiotlb not allocate a memory area spanning LLD's segment boundary. is_span_boundary() judges whether a memory area spans LLD's segment boundary. If map_single finds such a area, map_single tries to find the next available memory area. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Greg KH <greg@kroah.com> Cc: Jeff Garzik <jeff@garzik.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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59fc67dedb
commit
681cc5cd3e
1 changed files with 35 additions and 6 deletions
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@ -282,6 +282,15 @@ address_needs_mapping(struct device *hwdev, dma_addr_t addr)
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return (addr & ~mask) != 0;
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return (addr & ~mask) != 0;
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}
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}
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static inline unsigned int is_span_boundary(unsigned int index,
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unsigned int nslots,
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unsigned long offset_slots,
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unsigned long max_slots)
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{
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unsigned long offset = (offset_slots + index) & (max_slots - 1);
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return offset + nslots > max_slots;
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}
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/*
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/*
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* Allocates bounce buffer and returns its kernel virtual address.
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* Allocates bounce buffer and returns its kernel virtual address.
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*/
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*/
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@ -292,6 +301,16 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
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char *dma_addr;
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char *dma_addr;
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unsigned int nslots, stride, index, wrap;
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unsigned int nslots, stride, index, wrap;
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int i;
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int i;
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unsigned long start_dma_addr;
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unsigned long mask;
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unsigned long offset_slots;
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unsigned long max_slots;
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mask = dma_get_seg_boundary(hwdev);
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start_dma_addr = virt_to_bus(io_tlb_start) & mask;
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offset_slots = ALIGN(start_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
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max_slots = ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
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/*
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/*
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* For mappings greater than a page, we limit the stride (and
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* For mappings greater than a page, we limit the stride (and
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@ -311,10 +330,17 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
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*/
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*/
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spin_lock_irqsave(&io_tlb_lock, flags);
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spin_lock_irqsave(&io_tlb_lock, flags);
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{
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{
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wrap = index = ALIGN(io_tlb_index, stride);
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index = ALIGN(io_tlb_index, stride);
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if (index >= io_tlb_nslabs)
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if (index >= io_tlb_nslabs)
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wrap = index = 0;
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index = 0;
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while (is_span_boundary(index, nslots, offset_slots,
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max_slots)) {
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index += stride;
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if (index >= io_tlb_nslabs)
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index = 0;
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}
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wrap = index;
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do {
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do {
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/*
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/*
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@ -341,9 +367,12 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
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goto found;
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goto found;
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}
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}
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do {
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index += stride;
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index += stride;
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if (index >= io_tlb_nslabs)
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if (index >= io_tlb_nslabs)
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index = 0;
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index = 0;
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} while (is_span_boundary(index, nslots, offset_slots,
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max_slots));
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} while (index != wrap);
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} while (index != wrap);
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spin_unlock_irqrestore(&io_tlb_lock, flags);
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spin_unlock_irqrestore(&io_tlb_lock, flags);
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