[PATCH] mm/hmm: remove hmm_range_dma_map and hmm_range_dma_unmap

From: Christoph Hellwig <hch@lst.de>
To: jgg@ziepe.ca, jglisse@redhat.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH] mm/hmm: remove hmm_range_dma_map and hmm_range_dma_unmap
Date: Wed, 13 Nov 2019 14:45:28 +0100	[thread overview]
Message-ID: <20191113134528.21187-1-hch@lst.de> (raw)

These two functions have never been used since they were added.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/hmm.h |  23 -------
 mm/hmm.c            | 147 --------------------------------------------
 2 files changed, 170 deletions(-)

diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index b4af51735232..922c8d015cdb 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -230,34 +230,11 @@ static inline uint64_t hmm_device_entry_from_pfn(const struct hmm_range *range,
  * Please see Documentation/vm/hmm.rst for how to use the range API.
  */
 long hmm_range_fault(struct hmm_range *range, unsigned int flags);
-
-long hmm_range_dma_map(struct hmm_range *range,
-		       struct device *device,
-		       dma_addr_t *daddrs,
-		       unsigned int flags);
-long hmm_range_dma_unmap(struct hmm_range *range,
-			 struct device *device,
-			 dma_addr_t *daddrs,
-			 bool dirty);
 #else
 static inline long hmm_range_fault(struct hmm_range *range, unsigned int flags)
 {
 	return -EOPNOTSUPP;
 }
-
-static inline long hmm_range_dma_map(struct hmm_range *range,
-				     struct device *device, dma_addr_t *daddrs,
-				     unsigned int flags)
-{
-	return -EOPNOTSUPP;
-}
-
-static inline long hmm_range_dma_unmap(struct hmm_range *range,
-				       struct device *device,
-				       dma_addr_t *daddrs, bool dirty)
-{
-	return -EOPNOTSUPP;
-}
 #endif
 
 /*
diff --git a/mm/hmm.c b/mm/hmm.c
index 9e9d3f4ea17c..ab883eefe847 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -698,150 +698,3 @@ long hmm_range_fault(struct hmm_range *range, unsigned int flags)
 	return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT;
 }
 EXPORT_SYMBOL(hmm_range_fault);
-
-/**
- * hmm_range_dma_map - hmm_range_fault() and dma map page all in one.
- * @range:	range being faulted
- * @device:	device to map page to
- * @daddrs:	array of dma addresses for the mapped pages
- * @flags:	HMM_FAULT_*
- *
- * Return: the number of pages mapped on success (including zero), or any
- * status return from hmm_range_fault() otherwise.
- */
-long hmm_range_dma_map(struct hmm_range *range, struct device *device,
-		dma_addr_t *daddrs, unsigned int flags)
-{
-	unsigned long i, npages, mapped;
-	long ret;
-
-	ret = hmm_range_fault(range, flags);
-	if (ret <= 0)
-		return ret ? ret : -EBUSY;
-
-	npages = (range->end - range->start) >> PAGE_SHIFT;
-	for (i = 0, mapped = 0; i < npages; ++i) {
-		enum dma_data_direction dir = DMA_TO_DEVICE;
-		struct page *page;
-
-		/*
-		 * FIXME need to update DMA API to provide invalid DMA address
-		 * value instead of a function to test dma address value. This
-		 * would remove lot of dumb code duplicated accross many arch.
-		 *
-		 * For now setting it to 0 here is good enough as the pfns[]
-		 * value is what is use to check what is valid and what isn't.
-		 */
-		daddrs[i] = 0;
-
-		page = hmm_device_entry_to_page(range, range->pfns[i]);
-		if (page == NULL)
-			continue;
-
-		/* Check if range is being invalidated */
-		if (mmu_range_check_retry(range->notifier,
-					  range->notifier_seq)) {
-			ret = -EBUSY;
-			goto unmap;
-		}
-
-		/* If it is read and write than map bi-directional. */
-		if (range->pfns[i] & range->flags[HMM_PFN_WRITE])
-			dir = DMA_BIDIRECTIONAL;
-
-		daddrs[i] = dma_map_page(device, page, 0, PAGE_SIZE, dir);
-		if (dma_mapping_error(device, daddrs[i])) {
-			ret = -EFAULT;
-			goto unmap;
-		}
-
-		mapped++;
-	}
-
-	return mapped;
-
-unmap:
-	for (npages = i, i = 0; (i < npages) && mapped; ++i) {
-		enum dma_data_direction dir = DMA_TO_DEVICE;
-		struct page *page;
-
-		page = hmm_device_entry_to_page(range, range->pfns[i]);
-		if (page == NULL)
-			continue;
-
-		if (dma_mapping_error(device, daddrs[i]))
-			continue;
-
-		/* If it is read and write than map bi-directional. */
-		if (range->pfns[i] & range->flags[HMM_PFN_WRITE])
-			dir = DMA_BIDIRECTIONAL;
-
-		dma_unmap_page(device, daddrs[i], PAGE_SIZE, dir);
-		mapped--;
-	}
-
-	return ret;
-}
-EXPORT_SYMBOL(hmm_range_dma_map);
-
-/**
- * hmm_range_dma_unmap() - unmap range of that was map with hmm_range_dma_map()
- * @range: range being unmapped
- * @device: device against which dma map was done
- * @daddrs: dma address of mapped pages
- * @dirty: dirty page if it had the write flag set
- * Return: number of page unmapped on success, -EINVAL otherwise
- *
- * Note that caller MUST abide by mmu notifier or use HMM mirror and abide
- * to the sync_cpu_device_pagetables() callback so that it is safe here to
- * call set_page_dirty(). Caller must also take appropriate locks to avoid
- * concurrent mmu notifier or sync_cpu_device_pagetables() to make progress.
- */
-long hmm_range_dma_unmap(struct hmm_range *range,
-			 struct device *device,
-			 dma_addr_t *daddrs,
-			 bool dirty)
-{
-	unsigned long i, npages;
-	long cpages = 0;
-
-	/* Sanity check. */
-	if (range->end <= range->start)
-		return -EINVAL;
-	if (!daddrs)
-		return -EINVAL;
-	if (!range->pfns)
-		return -EINVAL;
-
-	npages = (range->end - range->start) >> PAGE_SHIFT;
-	for (i = 0; i < npages; ++i) {
-		enum dma_data_direction dir = DMA_TO_DEVICE;
-		struct page *page;
-
-		page = hmm_device_entry_to_page(range, range->pfns[i]);
-		if (page == NULL)
-			continue;
-
-		/* If it is read and write than map bi-directional. */
-		if (range->pfns[i] & range->flags[HMM_PFN_WRITE]) {
-			dir = DMA_BIDIRECTIONAL;
-
-			/*
-			 * See comments in function description on why it is
-			 * safe here to call set_page_dirty()
-			 */
-			if (dirty)
-				set_page_dirty(page);
-		}
-
-		/* Unmap and clear pfns/dma address */
-		dma_unmap_page(device, daddrs[i], PAGE_SIZE, dir);
-		range->pfns[i] = range->values[HMM_PFN_NONE];
-		/* FIXME see comments in hmm_vma_dma_map() */
-		daddrs[i] = 0;
-		cpages++;
-	}
-
-	return cpages;
-}
-EXPORT_SYMBOL(hmm_range_dma_unmap);
-- 
2.20.1

