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
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