Commit 72311809 authored by Tianyu Lan's avatar Tianyu Lan Committed by Christoph Hellwig
Browse files

swiotlb: clean up some coding style and minor issues 



- 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: default avatarTianyu Lan <tiala@microsoft.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent a45e52bf

Documentation/admin-guide/kernel-parameters.txt

+2 −1
Original line number Diff line number Diff line
@@ -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)

kernel/dma/swiotlb.c

+15 −11
Original line number Diff line number Diff line
@@ -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;