This is a pretty mechanical patch to make next patches simpler. New tce_iommu_unuse_page() helper does put_page() now but it might skip that after the memory registering patch applied.
As we are here, this removes unnecessary checks for a value returned by pfn_to_page() as it cannot possibly return NULL. Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> --- drivers/vfio/vfio_iommu_spapr_tce.c | 59 +++++++++++++++++++++++++++---------- 1 file changed, 44 insertions(+), 15 deletions(-) diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c index 67ea392..7fd60f9 100644 --- a/drivers/vfio/vfio_iommu_spapr_tce.c +++ b/drivers/vfio/vfio_iommu_spapr_tce.c @@ -217,25 +217,34 @@ static void tce_iommu_release(void *iommu_data) kfree(container); } +static void tce_iommu_unuse_page(struct tce_container *container, + unsigned long oldtce) +{ + struct page *page; + + if (!(oldtce & (TCE_PCI_READ | TCE_PCI_WRITE))) + return; + + page = pfn_to_page(__pa(oldtce) >> PAGE_SHIFT); + + if (oldtce & TCE_PCI_WRITE) + SetPageDirty(page); + + put_page(page); +} + static int tce_iommu_clear(struct tce_container *container, struct iommu_table *tbl, unsigned long entry, unsigned long pages) { unsigned long oldtce; - struct page *page; for ( ; pages; --pages, ++entry) { oldtce = iommu_clear_tce(tbl, entry); if (!oldtce) continue; - page = pfn_to_page(oldtce >> PAGE_SHIFT); - WARN_ON(!page); - if (page) { - if (oldtce & TCE_PCI_WRITE) - SetPageDirty(page); - put_page(page); - } + tce_iommu_unuse_page(container, (unsigned long) __va(oldtce)); } return 0; @@ -253,34 +262,54 @@ static enum dma_data_direction tce_iommu_direction(unsigned long tce) return DMA_NONE; } +static unsigned long tce_get_hva(struct tce_container *container, + unsigned page_shift, unsigned long tce) +{ + long ret; + struct page *page = NULL; + unsigned long hva; + enum dma_data_direction direction = tce_iommu_direction(tce); + + ret = get_user_pages_fast(tce & PAGE_MASK, 1, + direction != DMA_TO_DEVICE, &page); + if (unlikely(ret != 1)) + return -1; + + hva = (unsigned long) page_address(page); + + return hva; +} + static long tce_iommu_build(struct tce_container *container, struct iommu_table *tbl, unsigned long entry, unsigned long tce, unsigned long pages) { long i, ret = 0; - struct page *page = NULL; + struct page *page; unsigned long hva; enum dma_data_direction direction = tce_iommu_direction(tce); for (i = 0; i < pages; ++i) { - ret = get_user_pages_fast(tce & PAGE_MASK, 1, - direction != DMA_TO_DEVICE, &page); - if (unlikely(ret != 1)) { + hva = tce_get_hva(container, tbl->it_page_shift, tce); + if (hva == -1) { ret = -EFAULT; break; } + page = pfn_to_page(__pa(hva) >> PAGE_SHIFT); if (!tce_page_is_contained(page, tbl->it_page_shift)) { ret = -EPERM; break; } - hva = (unsigned long) page_address(page) + - (tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK); + /* Preserve offset within IOMMU page */ + hva |= tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK; + /* Preserve permission bits */ + hva |= tce & (TCE_PCI_READ | TCE_PCI_WRITE); ret = iommu_tce_build(tbl, entry + i, hva, direction); if (ret) { - put_page(page); + tce_iommu_unuse_page(container, hva); pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%ld\n", __func__, entry << tbl->it_page_shift, tce, ret); -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/