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From:   Leonardo Bras <leobras.c@gmail.com>
To:     Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
        Christophe Leroy <christophe.leroy@c-s.fr>,
        Leonardo Bras <leobras.c@gmail.com>,
        Joel Stanley <joel@jms.id.au>,
        Thiago Jung Bauermann <bauerman@linux.ibm.com>,
        Ram Pai <linuxram@us.ibm.com>,
        Brian King <brking@linux.vnet.ibm.com>,
        Murilo Fossa Vicentini <muvic@linux.ibm.com>,
        David Dai <zdai@linux.vnet.ibm.com>
Cc:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH v1 02/10] powerpc/kernel/iommu: Align size for IOMMU_PAGE_SIZE on iommu_*_coherent()
Date:   Mon, 17 Aug 2020 20:40:25 -0300
Message-Id: <20200817234033.442511-3-leobras.c@gmail.com>
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Both iommu_alloc_coherent() and iommu_free_coherent() assume that once
size is aligned to PAGE_SIZE it will be aligned to IOMMU_PAGE_SIZE.

Update those functions to guarantee alignment with requested size
using IOMMU_PAGE_ALIGN() before doing iommu_alloc() / iommu_free().

Also, on iommu_range_alloc(), replace ALIGN(n, 1 << tbl->it_page_shift)
with IOMMU_PAGE_ALIGN(n, tbl), which seems easier to read.

Signed-off-by: Leonardo Bras <leobras.c@gmail.com>
---
 arch/powerpc/kernel/iommu.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 9704f3f76e63..d7086087830f 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -237,10 +237,9 @@ static unsigned long iommu_range_alloc(struct device *dev,
 	}
 
 	if (dev)
-		boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
-				      1 << tbl->it_page_shift);
+		boundary_size = IOMMU_PAGE_ALIGN(dma_get_seg_boundary(dev) + 1, tbl);
 	else
-		boundary_size = ALIGN(1UL << 32, 1 << tbl->it_page_shift);
+		boundary_size = IOMMU_PAGE_ALIGN(1UL << 32, tbl);
 	/* 4GB boundary for iseries_hv_alloc and iseries_hv_map */
 
 	n = iommu_area_alloc(tbl->it_map, limit, start, npages, tbl->it_offset,
@@ -858,6 +857,7 @@ void *iommu_alloc_coherent(struct device *dev, struct iommu_table *tbl,
 	unsigned int order;
 	unsigned int nio_pages, io_order;
 	struct page *page;
+	size_t size_io = size;
 
 	size = PAGE_ALIGN(size);
 	order = get_order(size);
@@ -884,8 +884,9 @@ void *iommu_alloc_coherent(struct device *dev, struct iommu_table *tbl,
 	memset(ret, 0, size);
 
 	/* Set up tces to cover the allocated range */
-	nio_pages = size >> tbl->it_page_shift;
-	io_order = get_iommu_order(size, tbl);
+	size_io = IOMMU_PAGE_ALIGN(size_io, tbl);
+	nio_pages = size_io >> tbl->it_page_shift;
+	io_order = get_iommu_order(size_io, tbl);
 	mapping = iommu_alloc(dev, tbl, ret, nio_pages, DMA_BIDIRECTIONAL,
 			      mask >> tbl->it_page_shift, io_order, 0);
 	if (mapping == DMA_MAPPING_ERROR) {
@@ -900,11 +901,11 @@ void iommu_free_coherent(struct iommu_table *tbl, size_t size,
 			 void *vaddr, dma_addr_t dma_handle)
 {
 	if (tbl) {
-		unsigned int nio_pages;
+		size_t size_io = IOMMU_PAGE_ALIGN(size, tbl);
+		unsigned int nio_pages = size_io >> tbl->it_page_shift;
 
-		size = PAGE_ALIGN(size);
-		nio_pages = size >> tbl->it_page_shift;
 		iommu_free(tbl, dma_handle, nio_pages);
+
 		size = PAGE_ALIGN(size);
 		free_pages((unsigned long)vaddr, get_order(size));
 	}
-- 
2.25.4