[PATCH v4 2/9] swiotlb: Split size parameter to map/unmap APIs

Lu Baolu
2019-06-03T01:23:49Z

This splits the size parameter to swiotlb_tbl_map_single() and
swiotlb_tbl_unmap_single() into an alloc_size and a mapping_size
parameter, where the latter one is rounded up to the iommu page
size.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/xen/swiotlb-xen.c | 8 ++++----
include/linux/swiotlb.h | 8 ++++++--
kernel/dma/direct.c | 2 +-
kernel/dma/swiotlb.c | 24 +++++++++++++-----------
4 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 5dcb06fe9667..bb734f851d87 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -399,8 +399,8 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
*/
trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);

- map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
- attrs);
+ map = swiotlb_tbl_map_single(dev, start_dma_addr, phys,
+ size, size, dir, attrs);
if (map == DMA_MAPPING_ERROR)
return DMA_MAPPING_ERROR;

@@ -410,7 +410,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
* Ensure that the address returned is DMA'ble
*/
if (unlikely(!dma_capable(dev, dev_addr, size))) {
- swiotlb_tbl_unmap_single(dev, map, size, dir,
+ swiotlb_tbl_unmap_single(dev, map, size, size, dir,
attrs | DMA_ATTR_SKIP_CPU_SYNC);
return DMA_MAPPING_ERROR;
}
@@ -446,7 +446,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,

/* NOTE: We use dev_addr here, not paddr! */
if (is_xen_swiotlb_buffer(dev_addr))
- swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
+ swiotlb_tbl_unmap_single(hwdev, paddr, size, size, dir, attrs);
}

static void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 361f62bb4a8e..cde3dc18e21a 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -46,13 +46,17 @@ enum dma_sync_target {

extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
dma_addr_t tbl_dma_addr,
- phys_addr_t phys, size_t size,
+ phys_addr_t phys,
+ size_t mapping_size,
+ size_t alloc_size,
enum dma_data_direction dir,
unsigned long attrs);

extern void swiotlb_tbl_unmap_single(struct device *hwdev,
phys_addr_t tlb_addr,
- size_t size, enum dma_data_direction dir,
+ size_t mapping_size,
+ size_t alloc_size,
+ enum dma_data_direction dir,
unsigned long attrs);

extern void swiotlb_tbl_sync_single(struct device *hwdev,
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 2c2772e9702a..c892394bbe51 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -290,7 +290,7 @@ void dma_direct_unmap_page(struct device *dev, dma_addr_t addr,
dma_direct_sync_single_for_cpu(dev, addr, size, dir);

if (unlikely(is_swiotlb_buffer(phys)))
- swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs);
+ swiotlb_tbl_unmap_single(dev, phys, size, size, dir, attrs);
}
EXPORT_SYMBOL(dma_direct_unmap_page);

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 13f0cb080a4d..f956f785645a 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -442,7 +442,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,

phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
dma_addr_t tbl_dma_addr,
- phys_addr_t orig_addr, size_t size,
+ phys_addr_t orig_addr,
+ size_t mapping_size,
+ size_t alloc_size,
enum dma_data_direction dir,
unsigned long attrs)
{
@@ -479,8 +481,8 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
* For mappings greater than or equal to a page, we limit the stride
* (and hence alignment) to a page size.
*/
- nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
- if (size >= PAGE_SIZE)
+ nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ if (alloc_size >= PAGE_SIZE)
stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
else
stride = 1;
@@ -545,7 +547,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
spin_unlock_irqrestore(&io_tlb_lock, flags);
if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
- size, io_tlb_nslabs, tmp_io_tlb_used);
+ alloc_size, io_tlb_nslabs, tmp_io_tlb_used);
return DMA_MAPPING_ERROR;
found:
io_tlb_used += nslots;
@@ -560,7 +562,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT);
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
- swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE);
+ swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);

return tlb_addr;
}
@@ -569,11 +571,11 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
* tlb_addr is the physical address of the bounce buffer to unmap.
*/
void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
- size_t size, enum dma_data_direction dir,
- unsigned long attrs)
+ size_t mapping_size, size_t alloc_size,
+ enum dma_data_direction dir, unsigned long attrs)
{
unsigned long flags;
- int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
phys_addr_t orig_addr = io_tlb_orig_addr[index];

@@ -583,7 +585,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
if (orig_addr != INVALID_PHYS_ADDR &&
!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
- swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
+ swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_FROM_DEVICE);

/*
* Return the buffer to the free list by setting the corresponding
@@ -663,14 +665,14 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,

/* Oh well, have to allocate and map a bounce buffer. */
*phys = swiotlb_tbl_map_single(dev, __phys_to_dma(dev, io_tlb_start),
- *phys, size, dir, attrs);
+ *phys, size, size, dir, attrs);
if (*phys == DMA_MAPPING_ERROR)
return false;

/* Ensure that the address returned is DMA'ble */
*dma_addr = __phys_to_dma(dev, *phys);
if (unlikely(!dma_capable(dev, *dma_addr, size))) {
- swiotlb_tbl_unmap_single(dev, *phys, size, dir,
+ swiotlb_tbl_unmap_single(dev, *phys, size, size, dir,
attrs | DMA_ATTR_SKIP_CPU_SYNC);
return false;
}
--
2.17.1