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s390/pci_dma: split dma_update_trans
Split dma_update_trans into __dma_update_trans which handles updating the dma translation tables and __dma_purge_tlb which takes care of purging associated entries in the dma translation lookaside buffer. The map_sg API makes use of this split approach by calling __dma_update_trans once per physically contiguous address range but __dma_purge_tlb only once per dma contiguous address range. This results in less invocations of the expensive RPCIT instruction when using map_sg. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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parent
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commit
1f166e9e5c
1 changed files with 44 additions and 21 deletions
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@ -129,12 +129,11 @@ void dma_update_cpu_trans(unsigned long *entry, void *page_addr, int flags)
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entry_clr_protected(entry);
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}
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static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
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dma_addr_t dma_addr, size_t size, int flags)
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static int __dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
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dma_addr_t dma_addr, size_t size, int flags)
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{
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unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
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u8 *page_addr = (u8 *) (pa & PAGE_MASK);
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dma_addr_t start_dma_addr = dma_addr;
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unsigned long irq_flags;
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unsigned long *entry;
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int i, rc = 0;
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@ -145,7 +144,7 @@ static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
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spin_lock_irqsave(&zdev->dma_table_lock, irq_flags);
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if (!zdev->dma_table) {
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rc = -EINVAL;
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goto no_refresh;
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goto out_unlock;
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}
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for (i = 0; i < nr_pages; i++) {
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@ -159,20 +158,6 @@ static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
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dma_addr += PAGE_SIZE;
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}
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/*
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* With zdev->tlb_refresh == 0, rpcit is not required to establish new
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* translations when previously invalid translation-table entries are
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* validated. With lazy unmap, it also is skipped for previously valid
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* entries, but a global rpcit is then required before any address can
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* be re-used, i.e. after each iommu bitmap wrap-around.
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*/
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if (!zdev->tlb_refresh &&
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(!s390_iommu_strict ||
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((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)))
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goto no_refresh;
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rc = zpci_refresh_trans((u64) zdev->fh << 32, start_dma_addr,
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nr_pages * PAGE_SIZE);
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undo_cpu_trans:
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if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
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flags = ZPCI_PTE_INVALID;
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@ -185,12 +170,46 @@ static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
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dma_update_cpu_trans(entry, page_addr, flags);
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}
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}
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no_refresh:
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out_unlock:
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spin_unlock_irqrestore(&zdev->dma_table_lock, irq_flags);
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return rc;
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}
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static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,
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size_t size, int flags)
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{
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/*
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* With zdev->tlb_refresh == 0, rpcit is not required to establish new
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* translations when previously invalid translation-table entries are
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* validated. With lazy unmap, it also is skipped for previously valid
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* entries, but a global rpcit is then required before any address can
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* be re-used, i.e. after each iommu bitmap wrap-around.
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*/
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if (!zdev->tlb_refresh &&
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(!s390_iommu_strict ||
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((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)))
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return 0;
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return zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,
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PAGE_ALIGN(size));
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}
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static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
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dma_addr_t dma_addr, size_t size, int flags)
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{
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int rc;
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rc = __dma_update_trans(zdev, pa, dma_addr, size, flags);
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if (rc)
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return rc;
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rc = __dma_purge_tlb(zdev, dma_addr, size, flags);
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if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))
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__dma_update_trans(zdev, pa, dma_addr, size, ZPCI_PTE_INVALID);
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return rc;
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}
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void dma_free_seg_table(unsigned long entry)
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{
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unsigned long *sto = get_rt_sto(entry);
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@ -411,12 +430,16 @@ static int __s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
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for (s = sg; dma_addr < dma_addr_base + size; s = sg_next(s)) {
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pa = page_to_phys(sg_page(s)) + s->offset;
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ret = dma_update_trans(zdev, pa, dma_addr, s->length, flags);
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ret = __dma_update_trans(zdev, pa, dma_addr, s->length, flags);
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if (ret)
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goto unmap;
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dma_addr += s->length;
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}
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ret = __dma_purge_tlb(zdev, dma_addr_base, size, flags);
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if (ret)
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goto unmap;
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*handle = dma_addr_base;
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atomic64_add(size >> PAGE_SHIFT, &zdev->mapped_pages);
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