From: Christoph Hellwig <hch@lst.de>
To: "David S. Miller" <davem@davemloft.net>
Cc: Guenter Roeck <linux@roeck-us.net>,
sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 8/9] sparc/iommu: use __sbus_iommu_map_page to implement the map_sg path
Date: Tue, 16 Apr 2019 20:23:46 +0200 [thread overview]
Message-ID: <20190416182347.18441-9-hch@lst.de> (raw)
In-Reply-To: <20190416182347.18441-1-hch@lst.de>
This means we handle > PAGE_SIZE offsets fine, and grow the size check
so far only performed in the map_page path. We lose the optimization
to not double flush a page if it apears in multiple consecutive SG list
entries. But at least for block I/O those don't happen anymore since
we properly merge in higher layers anyway.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Guenter Roeck <linux@roeck-us.net>
---
arch/sparc/mm/iommu.c | 31 ++++++++++---------------------
1 file changed, 10 insertions(+), 21 deletions(-)
diff --git a/arch/sparc/mm/iommu.c b/arch/sparc/mm/iommu.c
index 37b5ce7657f6..8fbc08d14836 100644
--- a/arch/sparc/mm/iommu.c
+++ b/arch/sparc/mm/iommu.c
@@ -217,6 +217,11 @@ static dma_addr_t __sbus_iommu_map_page(struct device *dev, struct page *page,
if (!len || len > 256 * 1024)
return DMA_MAPPING_ERROR;
+ /*
+ * We expect unmapped highmem pages to be not in the cache.
+ * XXX Is this a good assumption?
+ * XXX What if someone else unmaps it here and races us?
+ */
if (per_page_flush && !PageHighMem(page)) {
unsigned long vaddr, p;
@@ -247,30 +252,14 @@ static int __sbus_iommu_map_sg(struct device *dev, struct scatterlist *sgl,
int nents, enum dma_data_direction dir, unsigned long attrs,
bool per_page_flush)
{
- unsigned long page, oldpage = 0;
struct scatterlist *sg;
- int i, j, n;
+ int j;
for_each_sg(sgl, sg, nents, j) {
- n = (sg->length + sg->offset + PAGE_SIZE-1) >> PAGE_SHIFT;
-
- /*
- * We expect unmapped highmem pages to be not in the cache.
- * XXX Is this a good assumption?
- * XXX What if someone else unmaps it here and races us?
- */
- if (per_page_flush && !PageHighMem(sg_page(sg))) {
- page = (unsigned long)page_address(sg_page(sg));
- for (i = 0; i < n; i++) {
- if (page != oldpage) { /* Already flushed? */
- flush_page_for_dma(page);
- oldpage = page;
- }
- page += PAGE_SIZE;
- }
- }
-
- sg->dma_address = iommu_get_one(dev, sg_phys(sg), n) + sg->offset;
+ sg->dma_address =__sbus_iommu_map_page(dev, sg_page(sg),
+ sg->offset, sg->length, per_page_flush);
+ if (sg->dma_address == DMA_MAPPING_ERROR)
+ return 0;
sg->dma_length = sg->length;
}
--
2.20.1
next prev parent reply other threads:[~2019-04-16 18:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-16 18:23 fix SG list handling in the sparc32 iommu driver Christoph Hellwig
2019-04-16 18:23 ` [PATCH 1/9] sparc/iommu: use !PageHighMem to check if a page has a kernel mapping Christoph Hellwig
2019-04-16 18:23 ` [PATCH 2/9] sparc/iommu: use sbus_iommu_unmap_page in sbus_iommu_unmap_sg Christoph Hellwig
2019-04-16 18:23 ` [PATCH 3/9] sparc/iommu: merge iommu_release_one and sbus_iommu_unmap_page Christoph Hellwig
2019-04-16 18:23 ` [PATCH 4/9] sparc/iommu: create a common helper for map_sg Christoph Hellwig
2019-04-16 18:23 ` [PATCH 5/9] sparc/iommu: pass a physical address to iommu_get_one Christoph Hellwig
2019-04-16 18:23 ` [PATCH 6/9] sparc/iommu: move per-page flushing into __sbus_iommu_map_page Christoph Hellwig
2019-04-16 18:23 ` [PATCH 7/9] sparc/iommu: fix __sbus_iommu_map_page for highmem pages Christoph Hellwig
2019-04-16 18:23 ` Christoph Hellwig [this message]
2019-04-16 18:23 ` [PATCH 9/9] sparc/iommu: merge iommu_get_one and __sbus_iommu_map_page Christoph Hellwig
2019-04-16 19:35 ` fix SG list handling in the sparc32 iommu driver Guenter Roeck
2019-04-30 13:17 ` Christoph Hellwig
2019-05-09 0:12 ` David Miller
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