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From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: linuxppc-dev@lists.ozlabs.org
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Alex Williamson <alex.williamson@redhat.com>,
	Gavin Shan <gwshan@linux.vnet.ibm.com>,
	Alexander Graf <agraf@suse.de>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v4 07/28] vfio: powerpc/spapr: Moving pinning/unpinning to helpers
Date: Mon, 16 Feb 2015 21:05:59 +1100	[thread overview]
Message-ID: <1424081180-4494-8-git-send-email-aik@ozlabs.ru> (raw)
In-Reply-To: <1424081180-4494-1-git-send-email-aik@ozlabs.ru>

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 <aik@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


  parent reply	other threads:[~2015-02-16 10:11 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-16 10:05 [PATCH v4 00/28] powerpc/iommu/vfio: Enable Dynamic DMA windows Alexey Kardashevskiy
2015-02-16 10:05 ` [PATCH v4 01/28] vfio: powerpc/spapr: Move page pinning from arch code to VFIO IOMMU driver Alexey Kardashevskiy
2015-02-16 10:05 ` [PATCH v4 02/28] vfio: powerpc/spapr: Do cleanup when releasing the group Alexey Kardashevskiy
2015-02-16 10:05 ` [PATCH v4 03/28] vfio: powerpc/spapr: Check that TCE page size is equal to it_page_size Alexey Kardashevskiy
2015-02-16 10:05 ` [PATCH v4 04/28] vfio: powerpc/spapr: Use it_page_size Alexey Kardashevskiy
2015-02-16 10:05 ` [PATCH v4 05/28] vfio: powerpc/spapr: Move locked_vm accounting to helpers Alexey Kardashevskiy
2015-02-16 10:05 ` [PATCH v4 06/28] vfio: powerpc/spapr: Disable DMA mappings on disabled container Alexey Kardashevskiy
2015-02-16 10:05 ` Alexey Kardashevskiy [this message]
2015-02-16 10:06 ` [PATCH v4 08/28] vfio: powerpc/spapr: Register memory Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 09/28] powerpc/powernv: Do not set "read" flag if direction==DMA_NONE Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 10/28] powerpc/iommu: Move tce_xxx callbacks from ppc_md to iommu_table Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 11/28] powerpc/iommu: Introduce iommu_table_alloc() helper Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 12/28] powerpc/spapr: vfio: Switch from iommu_table to new powerpc_iommu Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 13/28] powerpc/iommu: Fix IOMMU ownership control functions Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 14/28] vfio: powerpc/spapr: powerpc/powernv/ioda2: Rework IOMMU ownership control Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 15/28] powerpc/powernv/ioda/ioda2: Rework tce_build()/tce_free() Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 16/28] powerpc/iommu/powernv: Release replaced TCE Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 17/28] powerpc/pseries/lpar: Enable VFIO Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 18/28] poweppc/powernv/ioda2: Rework iommu_table creation Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 19/28] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_create_table Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 20/28] powerpc/powernv/ioda2: Introduce pnv_pci_ioda2_set_window Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 21/28] powerpc/iommu: Split iommu_free_table into 2 helpers Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 22/28] powerpc/powernv: Implement multilevel TCE tables Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 23/28] powerpc/powernv: Change prototypes to receive iommu Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 24/28] powerpc/powernv/ioda: Define and implement DMA table/window management callbacks Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 25/28] vfio: powerpc/spapr: powerpc/powernv/ioda2: Rework ownership Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 26/28] vfio: powerpc/spapr: Rework an IOMMU group attach/detach Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 27/28] vfio: powerpc/spapr: Register memory Alexey Kardashevskiy
2015-02-20  2:18   ` Alexey Kardashevskiy
2015-02-16 10:06 ` [PATCH v4 28/28] vfio: powerpc/spapr: Support Dynamic DMA windows Alexey Kardashevskiy

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