[RFC PATCH 3/7] swiotlb: Make io_tlb_overflow_buffer a physicaladdress
From: Alexander Duyck
Date: Wed Oct 03 2012 - 20:39:34 EST
This change makes it so that we can avoid virt_to_phys overhead when using the
io_tlb_overflow_buffer. My original plan was to completely remove the value
and replace it with a constant but I had seen that there were recent patches
that stated this couldn't be done until all device drivers that depended on
that functionality be updated.
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
---
lib/swiotlb.c | 61 ++++++++++++++++++++++++++++++++-------------------------
1 files changed, 34 insertions(+), 27 deletions(-)
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 02abb72..62848fb 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -70,7 +70,7 @@ static unsigned long io_tlb_nslabs;
*/
static unsigned long io_tlb_overflow = 32*1024;
-static void *io_tlb_overflow_buffer;
+phys_addr_t io_tlb_overflow_buffer;
/*
* This is a free list describing the number of free entries available from
@@ -138,6 +138,7 @@ void swiotlb_print_info(void)
void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
{
+ void *v_overflow_buffer;
unsigned long i, bytes;
bytes = nslabs << IO_TLB_SHIFT;
@@ -146,6 +147,15 @@ void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
io_tlb_start = __pa(tlb);
/*
+ * Get the overflow emergency buffer
+ */
+ v_overflow_buffer = alloc_bootmem_low_pages(PAGE_ALIGN(io_tlb_overflow));
+ if (!v_overflow_buffer)
+ panic("Cannot allocate SWIOTLB overflow buffer!\n");
+
+ io_tlb_overflow_buffer = __pa(v_overflow_buffer);
+
+ /*
* Allocate and initialize the free list array. This array is used
* to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
*/
@@ -155,12 +165,6 @@ void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
io_tlb_index = 0;
io_tlb_orig_addr = alloc_bootmem_pages(PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
- /*
- * Get the overflow emergency buffer
- */
- io_tlb_overflow_buffer = alloc_bootmem_low_pages(PAGE_ALIGN(io_tlb_overflow));
- if (!io_tlb_overflow_buffer)
- panic("Cannot allocate SWIOTLB overflow buffer!\n");
if (verbose)
swiotlb_print_info();
}
@@ -250,6 +254,7 @@ int
swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
{
unsigned long i, bytes;
+ unsigned char *v_overflow_buffer;
bytes = nslabs << IO_TLB_SHIFT;
@@ -259,13 +264,23 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
memset(tlb, 0, bytes);
/*
+ * Get the overflow emergency buffer
+ */
+ v_overflow_buffer = (void *)__get_free_pages(GFP_DMA,
+ get_order(io_tlb_overflow));
+ if (!v_overflow_buffer)
+ goto cleanup2;
+
+ io_tlb_overflow_buffer = virt_to_phys(v_overflow_buffer);
+
+ /*
* Allocate and initialize the free list array. This array is used
* to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
*/
io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL,
get_order(io_tlb_nslabs * sizeof(int)));
if (!io_tlb_list)
- goto cleanup2;
+ goto cleanup3;
for (i = 0; i < io_tlb_nslabs; i++)
io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
@@ -276,18 +291,10 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
get_order(io_tlb_nslabs *
sizeof(phys_addr_t)));
if (!io_tlb_orig_addr)
- goto cleanup3;
+ goto cleanup4;
memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(phys_addr_t));
- /*
- * Get the overflow emergency buffer
- */
- io_tlb_overflow_buffer = (void *)__get_free_pages(GFP_DMA,
- get_order(io_tlb_overflow));
- if (!io_tlb_overflow_buffer)
- goto cleanup4;
-
swiotlb_print_info();
late_alloc = 1;
@@ -295,13 +302,13 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
return 0;
cleanup4:
- free_pages((unsigned long)io_tlb_orig_addr,
- get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
- io_tlb_orig_addr = NULL;
-cleanup3:
free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
sizeof(int)));
io_tlb_list = NULL;
+cleanup3:
+ free_pages((unsigned long)v_overflow_buffer,
+ get_order(io_tlb_overflow));
+ io_tlb_overflow_buffer = 0;
cleanup2:
io_tlb_start = 0;
io_tlb_nslabs = 0;
@@ -310,11 +317,11 @@ cleanup2:
void __init swiotlb_free(void)
{
- if (!io_tlb_overflow_buffer)
+ if (!io_tlb_orig_addr)
return;
if (late_alloc) {
- free_pages((unsigned long)io_tlb_overflow_buffer,
+ free_pages((unsigned long)phys_to_virt(io_tlb_overflow_buffer),
get_order(io_tlb_overflow));
free_pages((unsigned long)io_tlb_orig_addr,
get_order(io_tlb_nslabs * sizeof(phys_addr_t)));
@@ -323,7 +330,7 @@ void __init swiotlb_free(void)
free_pages((unsigned long)phys_to_virt(io_tlb_start),
get_order(io_tlb_nslabs << IO_TLB_SHIFT));
} else {
- free_bootmem_late(__pa(io_tlb_overflow_buffer),
+ free_bootmem_late(io_tlb_overflow_buffer,
PAGE_ALIGN(io_tlb_overflow));
free_bootmem_late(__pa(io_tlb_orig_addr),
PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
@@ -694,7 +701,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
map = map_single(dev, phys, size, dir);
if (!map) {
swiotlb_full(dev, size, dir, 1);
- map = io_tlb_overflow_buffer;
+ return phys_to_dma(dev, io_tlb_overflow_buffer);
}
dev_addr = swiotlb_virt_to_bus(dev, map);
@@ -704,7 +711,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
*/
if (!dma_capable(dev, dev_addr, size)) {
swiotlb_tbl_unmap_single(dev, map, size, dir);
- dev_addr = swiotlb_virt_to_bus(dev, io_tlb_overflow_buffer);
+ return phys_to_dma(dev, io_tlb_overflow_buffer);
}
return dev_addr;
@@ -923,7 +930,7 @@ EXPORT_SYMBOL(swiotlb_sync_sg_for_device);
int
swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
{
- return (dma_addr == swiotlb_virt_to_bus(hwdev, io_tlb_overflow_buffer));
+ return (dma_addr == phys_to_dma(hwdev, io_tlb_overflow_buffer));
}
EXPORT_SYMBOL(swiotlb_dma_mapping_error);
--
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