Based-on-idea-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
---
include/linux/swiotlb.h | 25 ++++++
kernel/dma/swiotlb.c | 173 +++++++++++++++++++++++++++++++---------
2 files changed, 162 insertions(+), 36 deletions(-)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index 7ed35dd3de6e..489c249da434 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -62,6 +62,24 @@ dma_addr_t swiotlb_map(struct device *dev, phys_addr_t phys,
#ifdef CONFIG_SWIOTLB
extern enum swiotlb_force swiotlb_force;
+/**
+ * struct io_tlb_area - IO TLB memory area descriptor
+ *
+ * This is a single area with a single lock.
+ *
+ * @used: The number of used IO TLB block.
+ * @area_index: The index of to tlb area.
+ * @index: The slot index to start searching in this area for next round.
+ * @lock: The lock to protect the above data structures in the map and
+ * unmap calls.
+ */
+struct io_tlb_area {
+ unsigned long used;
+ unsigned int area_index;
+ unsigned int index;
+ spinlock_t lock;
+};
+
/**
* struct io_tlb_mem - IO TLB Memory Pool Descriptor
*
@@ -89,6 +107,9 @@ extern enum swiotlb_force swiotlb_force;
* @late_alloc: %true if allocated using the page allocator
* @force_bounce: %true if swiotlb bouncing is forced
* @for_alloc: %true if the pool is used for memory allocation
+ * @num_areas: The area number in the pool.
+ * @area_start: The area index to start searching in the next round.
+ * @area_nslabs: The slot number in the area.
*/
struct io_tlb_mem {
phys_addr_t start;
@@ -102,6 +123,10 @@ struct io_tlb_mem {
bool late_alloc;
bool force_bounce;
bool for_alloc;
+ unsigned int num_areas;
+ unsigned int area_start;
+ unsigned int area_nslabs;
+ struct io_tlb_area *areas;
struct io_tlb_slot {
phys_addr_t orig_addr;
size_t alloc_size;
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index e2ef0864eb1e..00a16f540f20 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -62,6 +62,8 @@
#define INVALID_PHYS_ADDR (~(phys_addr_t)0)
+#define NUM_AREAS_DEFAULT 1
+
static bool swiotlb_force_bounce;
static bool swiotlb_force_disable;
@@ -70,6 +72,25 @@ struct io_tlb_mem io_tlb_default_mem;
phys_addr_t swiotlb_unencrypted_base;
static unsigned long default_nslabs = IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT;
+static unsigned long default_area_num = NUM_AREAS_DEFAULT;
+
+static int swiotlb_setup_areas(struct io_tlb_mem *mem,
+ unsigned int num_areas, unsigned long nslabs)
+{
+ if (nslabs < 1 || !is_power_of_2(num_areas)) {
+ pr_err("swiotlb: Invalid areas parameter %d.\n", num_areas);
+ return -EINVAL;
+ }
+
+ /* Round up number of slabs to the next power of 2.
+ * The last area is going be smaller than the rest if default_nslabs is
+ * not power of two.
+ */
+ mem->area_start = 0;
+ mem->num_areas = num_areas;
+ mem->area_nslabs = nslabs / num_areas;
+ return 0;
+}
static int __init
setup_io_tlb_npages(char *str)
@@ -114,6 +135,8 @@ void __init swiotlb_adjust_size(unsigned long size)
return;
size = ALIGN(size, IO_TLB_SIZE);
default_nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
+ swiotlb_setup_areas(&io_tlb_default_mem, default_area_num,
+ default_nslabs);
pr_info("SWIOTLB bounce buffer size adjusted to %luMB", size >> 20);
}
@@ -195,7 +218,8 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
unsigned long nslabs, bool late_alloc)
{
void *vaddr = phys_to_virt(start);
- unsigned long bytes = nslabs << IO_TLB_SHIFT, i;
+ unsigned long bytes = nslabs << IO_TLB_SHIFT, i, j;
+ unsigned int block_list;
mem->nslabs = nslabs;
mem->start = start;
@@ -206,8 +230,13 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
if (swiotlb_force_bounce)
mem->force_bounce = true;
- spin_lock_init(&mem->lock);
- for (i = 0; i < mem->nslabs; i++) {
+ for (i = 0, j = 0, k = 0; i < mem->nslabs; i++) {
+ if (!(i % mem->area_nslabs)) {
+ mem->areas[j].index = 0;
+ spin_lock_init(&mem->areas[j].lock);
+ j++;
+ }
+
mem->slots[i].list = IO_TLB_SEGSIZE - io_tlb_offset(i);
mem->slots[i].orig_addr = INVALID_PHYS_ADDR;
mem->slots[i].alloc_size = 0;
@@ -272,6 +301,13 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags,
panic("%s: Failed to allocate %zu bytes align=0x%lx\n",
__func__, alloc_size, PAGE_SIZE);
+ swiotlb_setup_areas(&io_tlb_default_mem, default_area_num,
+ default_nslabs);
+ mem->areas = memblock_alloc(sizeof(struct io_tlb_area) * mem->num_areas,
+ SMP_CACHE_BYTES);
+ if (!mem->areas)
+ panic("%s: Failed to allocate mem->areas.\n", __func__);
+
swiotlb_init_io_tlb_mem(mem, __pa(tlb), default_nslabs, false);
mem->force_bounce = flags & SWIOTLB_FORCE;
@@ -296,7 +332,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask,
unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);
unsigned long bytes;
unsigned char *vstart = NULL;
- unsigned int order;
+ unsigned int order, area_order;
int rc = 0;
if (swiotlb_force_disable)
@@ -334,18 +370,32 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask,
goto retry;
}
+ swiotlb_setup_areas(&io_tlb_default_mem, default_area_num,
+ nslabs);
+
+ area_order = get_order(array_size(sizeof(*mem->areas),
+ default_area_num));
+ mem->areas = (struct io_tlb_area *)
+ __get_free_pages(GFP_KERNEL | __GFP_ZERO, area_order);
+ if (!mem->areas)
+ goto error_area;
+
mem->slots = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
get_order(array_size(sizeof(*mem->slots), nslabs)));
- if (!mem->slots) {
- free_pages((unsigned long)vstart, order);
- return -ENOMEM;
- }
+ if (!mem->slots)
+ goto error_slots;
set_memory_decrypted((unsigned long)vstart, bytes >> PAGE_SHIFT);
swiotlb_init_io_tlb_mem(mem, virt_to_phys(vstart), nslabs, true);
swiotlb_print_info();
return 0;
+
+error_slots:
+ free_pages((unsigned long)mem->areas, area_order);
+error_area:
+ free_pages((unsigned long)vstart, order);
+ return -ENOMEM;
}
void __init swiotlb_exit(void)
@@ -353,6 +403,7 @@ void __init swiotlb_exit(void)
struct io_tlb_mem *mem = &io_tlb_default_mem;
unsigned long tbl_vaddr;
size_t tbl_size, slots_size;
+ unsigned int area_order;
if (swiotlb_force_bounce)
return;
@@ -367,9 +418,14 @@ void __init swiotlb_exit(void)
set_memory_encrypted(tbl_vaddr, tbl_size >> PAGE_SHIFT);
if (mem->late_alloc) {
+ area_order = get_order(array_size(sizeof(*mem->areas),
+ mem->num_areas));
+ free_pages((unsigned long)mem->areas, area_order);
free_pages(tbl_vaddr, get_order(tbl_size));
free_pages((unsigned long)mem->slots, get_order(slots_size));
} else {
+ memblock_free_late(__pa(mem->areas),
+ mem->num_areas * sizeof(struct io_tlb_area));
memblock_free_late(mem->start, tbl_size);
memblock_free_late(__pa(mem->slots), slots_size);
}
@@ -472,9 +528,9 @@ static inline unsigned long get_max_slots(unsigned long boundary_mask)
return nr_slots(boundary_mask + 1);
}
-static unsigned int wrap_index(struct io_tlb_mem *mem, unsigned int index)
+static unsigned int wrap_area_index(struct io_tlb_mem *mem, unsigned int index)
{
- if (index >= mem->nslabs)
+ if (index >= mem->area_nslabs)
return 0;
return index;
}
@@ -483,10 +539,13 @@ static unsigned int wrap_index(struct io_tlb_mem *mem, unsigned int index)
* Find a suitable number of IO TLB entries size that will fit this request and
* allocate a buffer from that IO TLB pool.
*/
-static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
- size_t alloc_size, unsigned int alloc_align_mask)
+static int swiotlb_do_find_slots(struct io_tlb_mem *mem,
+ struct io_tlb_area *area,
+ int area_index,
+ struct device *dev, phys_addr_t orig_addr,
+ size_t alloc_size,
+ unsigned int alloc_align_mask)
{
- struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
unsigned long boundary_mask = dma_get_seg_boundary(dev);
dma_addr_t tbl_dma_addr =
phys_to_dma_unencrypted(dev, mem->start) & boundary_mask;
@@ -497,8 +556,11 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
unsigned int index, wrap, count = 0, i;
unsigned int offset = swiotlb_align_offset(dev, orig_addr);
unsigned long flags;
+ unsigned int slot_base;
+ unsigned int slot_index;
BUG_ON(!nslots);
+ BUG_ON(area_index >= mem->num_areas);
/*
* For mappings with an alignment requirement don't bother looping to
@@ -510,16 +572,20 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
stride = max(stride, stride << (PAGE_SHIFT - IO_TLB_SHIFT));
stride = max(stride, (alloc_align_mask >> IO_TLB_SHIFT) + 1);
- spin_lock_irqsave(&mem->lock, flags);
- if (unlikely(nslots > mem->nslabs - mem->used))
+ spin_lock_irqsave(&area->lock, flags);
+ if (unlikely(nslots > mem->area_nslabs - area->used))
goto not_found;
- index = wrap = wrap_index(mem, ALIGN(mem->index, stride));
+ slot_base = area_index * mem->area_nslabs;
+ index = wrap = wrap_area_index(mem, ALIGN(area->index, stride));
+
do {
+ slot_index = slot_base + index;
+
if (orig_addr &&
- (slot_addr(tbl_dma_addr, index) & iotlb_align_mask) !=
- (orig_addr & iotlb_align_mask)) {
- index = wrap_index(mem, index + 1);
+ (slot_addr(tbl_dma_addr, slot_index) &
+ iotlb_align_mask) != (orig_addr & iotlb_align_mask)) {
+ index = wrap_area_index(mem, index + 1);
continue;
}
@@ -528,26 +594,26 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
* contiguous buffers, we allocate the buffers from that slot
* and mark the entries as '0' indicating unavailable.
*/
- if (!iommu_is_span_boundary(index, nslots,
+ if (!iommu_is_span_boundary(slot_index, nslots,
nr_slots(tbl_dma_addr),
max_slots)) {
- if (mem->slots[index].list >= nslots)
+ if (mem->slots[slot_index].list >= nslots)
goto found;
}
- index = wrap_index(mem, index + stride);
+ index = wrap_area_index(mem, index + stride);
} while (index != wrap);
not_found:
- spin_unlock_irqrestore(&mem->lock, flags);
+ spin_unlock_irqrestore(&area->lock, flags);
return -1;
found:
- for (i = index; i < index + nslots; i++) {
+ for (i = slot_index; i < slot_index + nslots; i++) {
mem->slots[i].list = 0;
mem->slots[i].alloc_size =
- alloc_size - (offset + ((i - index) << IO_TLB_SHIFT));
+ alloc_size - (offset + ((i - slot_index) << IO_TLB_SHIFT));
}
- for (i = index - 1;
+ for (i = slot_index - 1;
io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 &&
mem->slots[i].list; i--)
mem->slots[i].list = ++count;
@@ -555,14 +621,45 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
/*
* Update the indices to avoid searching in the next round.
*/
- if (index + nslots < mem->nslabs)
- mem->index = index + nslots;
+ if (index + nslots < mem->area_nslabs)
+ area->index = index + nslots;
else
- mem->index = 0;
- mem->used += nslots;
+ area->index = 0;
+ area->used += nslots;
+ spin_unlock_irqrestore(&area->lock, flags);
+ return slot_index;
+}
- spin_unlock_irqrestore(&mem->lock, flags);
- return index;
+static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr,
+ size_t alloc_size, unsigned int alloc_align_mask)
+{
+ struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
+ int start, i, index;
+
+ i = start = mem->area_start;
+ mem->area_start = (mem->area_start + 1) % mem->num_areas;
+
+ do {
+ index = swiotlb_do_find_slots(mem, mem->areas + i, i,
+ dev, orig_addr, alloc_size,
+ alloc_align_mask);
+ if (index >= 0)
+ return index;
+ if (++i >= mem->num_areas)
+ i = 0;
+ } while (i != start);
+
+ return -1;
+}
+
+static unsigned long mem_used(struct io_tlb_mem *mem)
+{
+ int i;
+ unsigned long used = 0;
+
+ for (i = 0; i < mem->num_areas; i++)
+ used += mem->areas[i].used;
+ return used;
}
phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
@@ -594,7 +691,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr,
if (!(attrs & DMA_ATTR_NO_WARN))
dev_warn_ratelimited(dev,
"swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
- alloc_size, mem->nslabs, mem->used);
+ alloc_size, mem->nslabs, mem_used(mem));
return (phys_addr_t)DMA_MAPPING_ERROR;
}
@@ -624,6 +721,8 @@ static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr)
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];
int count, i;
/*
@@ -632,7 +731,9 @@ static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr)
* While returning the entries to the free list, we merge the entries
* with slots below and above the pool being returned.
*/
- spin_lock_irqsave(&mem->lock, flags);
+ BUG_ON(aindex >= mem->num_areas);
+
+ spin_lock_irqsave(&area->lock, flags);
if (index + nslots < ALIGN(index + 1, IO_TLB_SEGSIZE))
count = mem->slots[index + nslots].list;
else
@@ -656,8 +757,8 @@ static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr)
io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 && mem->slots[i].list;
i--)
mem->slots[i].list = ++count;
- mem->used -= nslots;
- spin_unlock_irqrestore(&mem->lock, flags);
+ area->used -= nslots;
+ spin_unlock_irqrestore(&area->lock, flags);
}
/*
