In 2.6.29 io_tlb_orig_addr[] got converted from storing virtual addresses
to storing physical ones. While checking virtual addresses against NULL
is a legitimate thing to catch invalid entries, checking physical ones
against zero isn't: There's no guarantee that PFN 0 is reserved on a
particular platform.
Since it is unclear whether the check in swiotlb_tbl_unmap_single() is
actually needed, retain it but check against a guaranteed invalid physical
address. This requires setting up the array in a suitable fashion. And
since the original code failed to invalidate array entries when regions
get unmapped, this is being fixed at once along with adding a similar
check to swiotlb_tbl_sync_single().
Obviously the less intrusive change would be to simply drop the check in
swiotlb_tbl_unmap_single().
Signed-off-by: Jan Beulich <jbeul...@suse.com>
---
lib/swiotlb.c | 28 ++++++++++++++++++----------
1 file changed, 18 insertions(+), 10 deletions(-)
--- 3.15-rc8/lib/swiotlb.c
+++ 3.15-rc8-swiotlb-unmap-single-phys-check/lib/swiotlb.c
@@ -86,6 +86,7 @@ static unsigned int io_tlb_index;
* We need to save away the original address corresponding to a mapped entry
* for the sync operations.
*/
+#define INVALID_PHYS_ADDR (~(phys_addr_t)0)
static phys_addr_t *io_tlb_orig_addr;
/*
@@ -188,12 +189,14 @@ int __init swiotlb_init_with_tbl(char *t
io_tlb_list = memblock_virt_alloc(
PAGE_ALIGN(io_tlb_nslabs * sizeof(int)),
PAGE_SIZE);
- 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 = memblock_virt_alloc(
PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)),
PAGE_SIZE);
+ for (i = 0; i < io_tlb_nslabs; i++) {
+ io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+ io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+ }
+ io_tlb_index = 0;
if (verbose)
swiotlb_print_info();
@@ -313,10 +316,6 @@ swiotlb_late_init_with_tbl(char *tlb, un
if (!io_tlb_list)
goto cleanup3;
- 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 = (phys_addr_t *)
__get_free_pages(GFP_KERNEL,
get_order(io_tlb_nslabs *
@@ -324,7 +323,11 @@ swiotlb_late_init_with_tbl(char *tlb, un
if (!io_tlb_orig_addr)
goto cleanup4;
- memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(phys_addr_t));
+ for (i = 0; i < io_tlb_nslabs; i++) {
+ io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+ io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+ }
+ io_tlb_index = 0;
swiotlb_print_info();
@@ -556,7 +559,8 @@ void swiotlb_tbl_unmap_single(struct dev
/*
* First, sync the memory before unmapping the entry
*/
- if (orig_addr && ((dir == DMA_FROM_DEVICE) || (dir ==
DMA_BIDIRECTIONAL)))
+ if (orig_addr != INVALID_PHYS_ADDR &&
+ ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
/*
@@ -573,8 +577,10 @@ void swiotlb_tbl_unmap_single(struct dev
* Step 1: return the slots to the free list, merging the
* slots with superceeding slots
*/
- for (i = index + nslots - 1; i >= index; i--)
+ for (i = index + nslots - 1; i >= index; i--) {
io_tlb_list[i] = ++count;
+ io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
+ }
/*
* Step 2: merge the returned slots with the preceding slots,
* if available (non zero)
@@ -593,6 +599,8 @@ void swiotlb_tbl_sync_single(struct devi
int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT;
phys_addr_t orig_addr = io_tlb_orig_addr[index];
+ if (orig_addr == INVALID_PHYS_ADDR)
+ return;
orig_addr += (unsigned long)tlb_addr & ((1 << IO_TLB_SHIFT) - 1);
switch (target) {
--
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