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Subject[PATCH 1 of 9] revert "swiotlb: support bouncing of HighMem pages."
Date
From
git commit ef9b189352f2eb78f14e52996f4780a523b04a49

---
lib/swiotlb.c | 122 +++++++++++++++------------------------------------------
1 file changed, 33 insertions(+), 89 deletions(-)
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -26,7 +26,6 @@
#include <linux/swiotlb.h>
#include <linux/types.h>
#include <linux/ctype.h>
-#include <linux/highmem.h>

#include <asm/io.h>
#include <asm/dma.h>
@@ -39,6 +38,9 @@
#define OFFSET(val,align) ((unsigned long) \
( (val) & ( (align) - 1)))

+#define SG_ENT_VIRT_ADDRESS(sg) (sg_virt((sg)))
+#define SG_ENT_PHYS_ADDRESS(sg) virt_to_bus(SG_ENT_VIRT_ADDRESS(sg))
+
#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))

/*
@@ -89,10 +91,7 @@
* We need to save away the original address corresponding to a mapped entry
* for the sync operations.
*/
-static struct swiotlb_phys_addr {
- struct page *page;
- unsigned int offset;
-} *io_tlb_orig_addr;
+static unsigned char **io_tlb_orig_addr;

/*
* Protect the above data structures in the map and unmap calls
@@ -151,11 +150,6 @@
return 0;
}

-static dma_addr_t swiotlb_sg_to_bus(struct scatterlist *sg)
-{
- return swiotlb_phys_to_bus(page_to_phys(sg_page(sg)) + sg->offset);
-}
-
static void swiotlb_print_info(unsigned long bytes)
{
phys_addr_t pstart, pend;
@@ -215,7 +209,7 @@
for (i = 0; i < io_tlb_nslabs; i++)
io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
io_tlb_index = 0;
- io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(struct swiotlb_phys_addr));
+ io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(char *));

/*
* Get the overflow emergency buffer
@@ -289,12 +283,12 @@
io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
io_tlb_index = 0;

- io_tlb_orig_addr = (struct swiotlb_phys_addr *)__get_free_pages(GFP_KERNEL,
- get_order(io_tlb_nslabs * sizeof(struct swiotlb_phys_addr)));
+ io_tlb_orig_addr = (unsigned char **)__get_free_pages(GFP_KERNEL,
+ get_order(io_tlb_nslabs * sizeof(char *)));
if (!io_tlb_orig_addr)
goto cleanup3;

- memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(struct swiotlb_phys_addr));
+ memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(char *));

/*
* Get the overflow emergency buffer
@@ -341,59 +335,20 @@
return addr >= io_tlb_start && addr < io_tlb_end;
}

-static struct swiotlb_phys_addr swiotlb_bus_to_phys_addr(char *dma_addr)
+static void
+__sync_single(char *buffer, char *dma_addr, size_t size, int dir)
{
- int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
- struct swiotlb_phys_addr buffer = io_tlb_orig_addr[index];
- buffer.offset += (long)dma_addr & ((1 << IO_TLB_SHIFT) - 1);
- buffer.page += buffer.offset >> PAGE_SHIFT;
- buffer.offset &= PAGE_SIZE - 1;
- return buffer;
-}
-
-static void
-__sync_single(struct swiotlb_phys_addr buffer, char *dma_addr, size_t size, int dir)
-{
- if (PageHighMem(buffer.page)) {
- size_t len, bytes;
- char *dev, *host, *kmp;
-
- len = size;
- while (len != 0) {
- unsigned long flags;
-
- bytes = len;
- if ((bytes + buffer.offset) > PAGE_SIZE)
- bytes = PAGE_SIZE - buffer.offset;
- local_irq_save(flags); /* protects KM_BOUNCE_READ */
- kmp = kmap_atomic(buffer.page, KM_BOUNCE_READ);
- dev = dma_addr + size - len;
- host = kmp + buffer.offset;
- if (dir == DMA_FROM_DEVICE)
- memcpy(host, dev, bytes);
- else
- memcpy(dev, host, bytes);
- kunmap_atomic(kmp, KM_BOUNCE_READ);
- local_irq_restore(flags);
- len -= bytes;
- buffer.page++;
- buffer.offset = 0;
- }
- } else {
- void *v = page_address(buffer.page) + buffer.offset;
-
- if (dir == DMA_TO_DEVICE)
- memcpy(dma_addr, v, size);
- else
- memcpy(v, dma_addr, size);
- }
+ if (dir == DMA_TO_DEVICE)
+ memcpy(dma_addr, buffer, size);
+ else
+ memcpy(buffer, dma_addr, size);
}

/*
* Allocates bounce buffer and returns its kernel virtual address.
*/
static void *
-map_single(struct device *hwdev, struct swiotlb_phys_addr buffer, size_t size, int dir)
+map_single(struct device *hwdev, char *buffer, size_t size, int dir)
{
unsigned long flags;
char *dma_addr;
@@ -403,7 +358,6 @@
unsigned long mask;
unsigned long offset_slots;
unsigned long max_slots;
- struct swiotlb_phys_addr slot_buf;

mask = dma_get_seg_boundary(hwdev);
start_dma_addr = swiotlb_virt_to_bus(io_tlb_start) & mask;
@@ -488,13 +442,8 @@
* This is needed when we sync the memory. Then we sync the buffer if
* needed.
*/
- slot_buf = buffer;
- for (i = 0; i < nslots; i++) {
- slot_buf.page += slot_buf.offset >> PAGE_SHIFT;
- slot_buf.offset &= PAGE_SIZE - 1;
- io_tlb_orig_addr[index+i] = slot_buf;
- slot_buf.offset += 1 << IO_TLB_SHIFT;
- }
+ for (i = 0; i < nslots; i++)
+ io_tlb_orig_addr[index+i] = buffer + (i << IO_TLB_SHIFT);
if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
__sync_single(buffer, dma_addr, size, DMA_TO_DEVICE);

@@ -510,12 +459,12 @@
unsigned long flags;
int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
- struct swiotlb_phys_addr buffer = swiotlb_bus_to_phys_addr(dma_addr);
+ char *buffer = io_tlb_orig_addr[index];

/*
* First, sync the memory before unmapping the entry
*/
- if ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))
+ if (buffer && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
/*
* bounce... copy the data back into the original buffer * and
* delete the bounce buffer.
@@ -552,7 +501,10 @@
sync_single(struct device *hwdev, char *dma_addr, size_t size,
int dir, int target)
{
- struct swiotlb_phys_addr buffer = swiotlb_bus_to_phys_addr(dma_addr);
+ int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
+ char *buffer = io_tlb_orig_addr[index];
+
+ buffer += ((unsigned long)dma_addr & ((1 << IO_TLB_SHIFT) - 1));

switch (target) {
case SYNC_FOR_CPU:
@@ -600,10 +552,7 @@
* swiotlb_map_single(), which will grab memory from
* the lowest available address range.
*/
- struct swiotlb_phys_addr buffer;
- buffer.page = virt_to_page(NULL);
- buffer.offset = 0;
- ret = map_single(hwdev, buffer, size, DMA_FROM_DEVICE);
+ ret = map_single(hwdev, NULL, size, DMA_FROM_DEVICE);
if (!ret)
return NULL;
}
@@ -671,7 +620,6 @@
{
dma_addr_t dev_addr = swiotlb_virt_to_bus(ptr);
void *map;
- struct swiotlb_phys_addr buffer;

BUG_ON(dir == DMA_NONE);
/*
@@ -686,9 +634,7 @@
/*
* Oh well, have to allocate and map a bounce buffer.
*/
- buffer.page = virt_to_page(ptr);
- buffer.offset = (unsigned long)ptr & ~PAGE_MASK;
- map = map_single(hwdev, buffer, size, dir);
+ map = map_single(hwdev, ptr, size, dir);
if (!map) {
swiotlb_full(hwdev, size, dir, 1);
map = io_tlb_overflow_buffer;
@@ -833,20 +779,18 @@
int dir, struct dma_attrs *attrs)
{
struct scatterlist *sg;
- struct swiotlb_phys_addr buffer;
+ void *addr;
dma_addr_t dev_addr;
int i;

BUG_ON(dir == DMA_NONE);

for_each_sg(sgl, sg, nelems, i) {
- dev_addr = swiotlb_sg_to_bus(sg);
+ addr = SG_ENT_VIRT_ADDRESS(sg);
+ dev_addr = swiotlb_virt_to_bus(addr);
if (range_needs_mapping(sg_virt(sg), sg->length) ||
address_needs_mapping(hwdev, dev_addr, sg->length)) {
- void *map;
- buffer.page = sg_page(sg);
- buffer.offset = sg->offset;
- map = map_single(hwdev, buffer, sg->length, dir);
+ void *map = map_single(hwdev, addr, sg->length, dir);
if (!map) {
/* Don't panic here, we expect map_sg users
to do proper error handling. */
@@ -886,11 +830,11 @@
BUG_ON(dir == DMA_NONE);

for_each_sg(sgl, sg, nelems, i) {
- if (sg->dma_address != swiotlb_sg_to_bus(sg))
+ if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
unmap_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
sg->dma_length, dir);
else if (dir == DMA_FROM_DEVICE)
- dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
+ dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
}
}
EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
@@ -919,11 +863,11 @@
BUG_ON(dir == DMA_NONE);

for_each_sg(sgl, sg, nelems, i) {
- if (sg->dma_address != swiotlb_sg_to_bus(sg))
+ if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
sync_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
sg->dma_length, dir, target);
else if (dir == DMA_FROM_DEVICE)
- dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
+ dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
}
}




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