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swiotlb: clean up some coding style and minor issues

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- Fix the used field of struct io_tlb_area wasn't initialized
- Set area number to be 0 if input area number parameter is 0
- Use array_size() to calculate io_tlb_area array size
- Make parameters of swiotlb_do_find_slots() more reasonable

Fixes: 26ffb91fa5e0 ("swiotlb: split up the global swiotlb lock")
Signed-off-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Tianyu Lan 2022-07-21 23:38:46 -04:00 committed by Christoph Hellwig
parent a45e52bf1e
commit 7231180903
2 changed files with 17 additions and 12 deletions
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3
Documentation/admin-guide/kernel-parameters.txt
View File

@ -5907,7 +5907,8 @@
Format: { <int> [,<int>] | force | noforce }
<int> -- Number of I/O TLB slabs
<int> -- Second integer after comma. Number of swiotlb
areas with their own lock. Must be power of 2.
areas with their own lock. Will be rounded up
to a power of 2.
force -- force using of bounce buffers even if they
wouldn't be automatically used by the kernel
noforce -- Never use bounce buffers (for debugging)

26
kernel/dma/swiotlb.c
View File

@ -119,7 +119,10 @@ static bool round_up_default_nslabs(void)
static void swiotlb_adjust_nareas(unsigned int nareas)
{
if (!is_power_of_2(nareas))
/* use a single area when non is specified */
if (!nareas)
nareas = 1;
else if (!is_power_of_2(nareas))
nareas = roundup_pow_of_two(nareas);
default_nareas = nareas;
@ -276,6 +279,7 @@ static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start,
for (i = 0; i < mem->nareas; i++) {
spin_lock_init(&mem->areas[i].lock);
mem->areas[i].index = 0;
mem->areas[i].used = 0;
}
for (i = 0; i < mem->nslabs; i++) {
@ -358,8 +362,8 @@ 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);
mem->areas = memblock_alloc(sizeof(struct io_tlb_area) *
default_nareas, SMP_CACHE_BYTES);
mem->areas = memblock_alloc(array_size(sizeof(struct io_tlb_area),
default_nareas), SMP_CACHE_BYTES);
if (!mem->areas)
panic("%s: Failed to allocate mem->areas.\n", __func__);
@ -484,7 +488,7 @@ void __init swiotlb_exit(void)
free_pages((unsigned long)mem->slots, get_order(slots_size));
} else {
memblock_free_late(__pa(mem->areas),
mem->nareas * sizeof(struct io_tlb_area));
array_size(sizeof(*mem->areas), mem->nareas));
memblock_free_late(mem->start, tbl_size);
memblock_free_late(__pa(mem->slots), slots_size);
}
@ -598,11 +602,12 @@ static unsigned int wrap_area_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_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)
static int swiotlb_do_find_slots(struct device *dev, int area_index,
phys_addr_t orig_addr, size_t alloc_size,
unsigned int alloc_align_mask)
{
struct io_tlb_mem *mem = dev->dma_io_tlb_mem;
struct io_tlb_area *area = mem->areas + area_index;
unsigned long boundary_mask = dma_get_seg_boundary(dev);
dma_addr_t tbl_dma_addr =
phys_to_dma_unencrypted(dev, mem->start) & boundary_mask;
@ -691,12 +696,11 @@ 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 = raw_smp_processor_id() & ((1U << __fls(mem->nareas)) - 1);
int start = raw_smp_processor_id() & (mem->nareas - 1);
int i = start, index;
do {
index = swiotlb_do_find_slots(mem, mem->areas + i, i,
dev, orig_addr, alloc_size,
index = swiotlb_do_find_slots(dev, i, orig_addr, alloc_size,
alloc_align_mask);
if (index >= 0)
return index;