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-rw-r--r--kernel/dma/swiotlb.c91
1 files changed, 58 insertions, 33 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 86fe172b5958..a5e0dfc44d24 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -69,11 +69,14 @@
* @alloc_size: Size of the allocated buffer.
* @list: The free list describing the number of free entries available
* from each index.
+ * @pad_slots: Number of preceding padding slots. Valid only in the first
+ * allocated non-padding slot.
*/
struct io_tlb_slot {
phys_addr_t orig_addr;
size_t alloc_size;
- unsigned int list;
+ unsigned short list;
+ unsigned short pad_slots;
};
static bool swiotlb_force_bounce;
@@ -287,6 +290,7 @@ static void swiotlb_init_io_tlb_pool(struct io_tlb_pool *mem, phys_addr_t start,
mem->nslabs - i);
mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
mem->slots[i].alloc_size = 0;
+ mem->slots[i].pad_slots = 0;
}
memset(vaddr, 0, bytes);
@@ -821,12 +825,30 @@ void swiotlb_dev_init(struct device *dev)
#endif
}
-/*
- * Return the offset into a iotlb slot required to keep the device happy.
+/**
+ * swiotlb_align_offset() - Get required offset into an IO TLB allocation.
+ * @dev: Owning device.
+ * @align_mask: Allocation alignment mask.
+ * @addr: DMA address.
+ *
+ * Return the minimum offset from the start of an IO TLB allocation which is
+ * required for a given buffer address and allocation alignment to keep the
+ * device happy.
+ *
+ * First, the address bits covered by min_align_mask must be identical in the
+ * original address and the bounce buffer address. High bits are preserved by
+ * choosing a suitable IO TLB slot, but bits below IO_TLB_SHIFT require extra
+ * padding bytes before the bounce buffer.
+ *
+ * Second, @align_mask specifies which bits of the first allocated slot must
+ * be zero. This may require allocating additional padding slots, and then the
+ * offset (in bytes) from the first such padding slot is returned.
*/
-static unsigned int swiotlb_align_offset(struct device *dev, u64 addr)
+static unsigned int swiotlb_align_offset(struct device *dev,
+ unsigned int align_mask, u64 addr)
{
- return addr & dma_get_min_align_mask(dev) & (IO_TLB_SIZE - 1);
+ return addr & dma_get_min_align_mask(dev) &
+ (align_mask | (IO_TLB_SIZE - 1));
}
/*
@@ -841,27 +863,23 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size
size_t alloc_size = mem->slots[index].alloc_size;
unsigned long pfn = PFN_DOWN(orig_addr);
unsigned char *vaddr = mem->vaddr + tlb_addr - mem->start;
- unsigned int tlb_offset, orig_addr_offset;
+ int tlb_offset;
if (orig_addr == INVALID_PHYS_ADDR)
return;
- tlb_offset = tlb_addr & (IO_TLB_SIZE - 1);
- orig_addr_offset = swiotlb_align_offset(dev, orig_addr);
- if (tlb_offset < orig_addr_offset) {
- dev_WARN_ONCE(dev, 1,
- "Access before mapping start detected. orig offset %u, requested offset %u.\n",
- orig_addr_offset, tlb_offset);
- return;
- }
-
- tlb_offset -= orig_addr_offset;
- if (tlb_offset > alloc_size) {
- dev_WARN_ONCE(dev, 1,
- "Buffer overflow detected. Allocation size: %zu. Mapping size: %zu+%u.\n",
- alloc_size, size, tlb_offset);
- return;
- }
+ /*
+ * It's valid for tlb_offset to be negative. This can happen when the
+ * "offset" returned by swiotlb_align_offset() is non-zero, and the
+ * tlb_addr is pointing within the first "offset" bytes of the second
+ * or subsequent slots of the allocated swiotlb area. While it's not
+ * valid for tlb_addr to be pointing within the first "offset" bytes
+ * of the first slot, there's no way to check for such an error since
+ * this function can't distinguish the first slot from the second and
+ * subsequent slots.
+ */
+ tlb_offset = (tlb_addr & (IO_TLB_SIZE - 1)) -
+ swiotlb_align_offset(dev, 0, orig_addr);
orig_addr += tlb_offset;
alloc_size -= tlb_offset;
@@ -1005,7 +1023,7 @@ static int swiotlb_search_pool_area(struct device *dev, struct io_tlb_pool *pool
unsigned long max_slots = get_max_slots(boundary_mask);
unsigned int iotlb_align_mask = dma_get_min_align_mask(dev);
unsigned int nslots = nr_slots(alloc_size), stride;
- unsigned int offset = swiotlb_align_offset(dev, orig_addr);
+ unsigned int offset = swiotlb_align_offset(dev, 0, orig_addr);
unsigned int index, slots_checked, count = 0, i;
unsigned long flags;
unsigned int slot_base;
@@ -1328,11 +1346,12 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
unsigned long attrs)
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
- unsigned int offset = swiotlb_align_offset(dev, orig_addr);
+ unsigned int offset;
struct io_tlb_pool *pool;
unsigned int i;
int index;
phys_addr_t tlb_addr;
+ unsigned short pad_slots;
if (!mem || !mem->nslabs) {
dev_warn_ratelimited(dev,
@@ -1349,6 +1368,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
return (phys_addr_t)DMA_MAPPING_ERROR;
}
+ offset = swiotlb_align_offset(dev, alloc_align_mask, orig_addr);
index = swiotlb_find_slots(dev, orig_addr,
alloc_size + offset, alloc_align_mask, &pool);
if (index == -1) {
@@ -1364,6 +1384,10 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
* This is needed when we sync the memory. Then we sync the buffer if
* needed.
*/
+ pad_slots = offset >> IO_TLB_SHIFT;
+ offset &= (IO_TLB_SIZE - 1);
+ index += pad_slots;
+ pool->slots[index].pad_slots = pad_slots;
for (i = 0; i < nr_slots(alloc_size + offset); i++)
pool->slots[index + i].orig_addr = slot_addr(orig_addr, i);
tlb_addr = slot_addr(pool->start, index) + offset;
@@ -1384,13 +1408,17 @@ static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr)
{
struct io_tlb_pool *mem = swiotlb_find_pool(dev, tlb_addr);
unsigned long flags;
- unsigned int offset = swiotlb_align_offset(dev, tlb_addr);
- int index = (tlb_addr - offset - mem->start) >> IO_TLB_SHIFT;
- int nslots = nr_slots(mem->slots[index].alloc_size + offset);
- int aindex = index / mem->area_nslabs;
- struct io_tlb_area *area = &mem->areas[aindex];
+ unsigned int offset = swiotlb_align_offset(dev, 0, tlb_addr);
+ int index, nslots, aindex;
+ struct io_tlb_area *area;
int count, i;
+ index = (tlb_addr - offset - mem->start) >> IO_TLB_SHIFT;
+ index -= mem->slots[index].pad_slots;
+ nslots = nr_slots(mem->slots[index].alloc_size + offset);
+ aindex = index / mem->area_nslabs;
+ area = &mem->areas[aindex];
+
/*
* Return the buffer to the free list by setting the corresponding
* entries to indicate the number of contiguous entries available.
@@ -1413,6 +1441,7 @@ static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr)
mem->slots[i].list = ++count;
mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
mem->slots[i].alloc_size = 0;
+ mem->slots[i].pad_slots = 0;
}
/*
@@ -1647,9 +1676,6 @@ DEFINE_DEBUGFS_ATTRIBUTE(fops_io_tlb_hiwater, io_tlb_hiwater_get,
static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem,
const char *dirname)
{
- atomic_long_set(&mem->total_used, 0);
- atomic_long_set(&mem->used_hiwater, 0);
-
mem->debugfs = debugfs_create_dir(dirname, io_tlb_default_mem.debugfs);
if (!mem->nslabs)
return;
@@ -1660,7 +1686,6 @@ static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem,
debugfs_create_file("io_tlb_used_hiwater", 0600, mem->debugfs, mem,
&fops_io_tlb_hiwater);
#ifdef CONFIG_SWIOTLB_DYNAMIC
- atomic_long_set(&mem->transient_nslabs, 0);
debugfs_create_file("io_tlb_transient_nslabs", 0400, mem->debugfs,
mem, &fops_io_tlb_transient_used);
#endif