Commit f71f6421 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'dma-mapping-6.5-2023-07-09' of git://git.infradead.org/users/hch/dma-mapping 

Pull dma-mapping fixes from Christoph Hellwig:

 - swiotlb area sizing fixes (Petr Tesarik)

* tag 'dma-mapping-6.5-2023-07-09' of git://git.infradead.org/users/hch/dma-mapping:
  swiotlb: reduce the number of areas to match actual memory pool size
  swiotlb: always set the number of areas before allocating the pool
parents a9943ad3 8ac04063

kernel/dma/swiotlb.c

+35 −11
Original line number Diff line number Diff line
@@ -115,9 +115,16 @@ static bool round_up_default_nslabs(void) 
	return true;

}



/**

 * swiotlb_adjust_nareas() - adjust the number of areas and slots

 * @nareas:	Desired number of areas. Zero is treated as 1.

 *

 * Adjust the default number of areas in a memory pool.

 * The default size of the memory pool may also change to meet minimum area

 * size requirements.

 */

static void swiotlb_adjust_nareas(unsigned int nareas)

{

	/* use a single area when non is specified */

	if (!nareas)

		nareas = 1;

	else if (!is_power_of_2(nareas))
@@ -131,6 +138,23 @@ static void swiotlb_adjust_nareas(unsigned int nareas) 
			(default_nslabs << IO_TLB_SHIFT) >> 20);

}



/**

 * limit_nareas() - get the maximum number of areas for a given memory pool size

 * @nareas:	Desired number of areas.

 * @nslots:	Total number of slots in the memory pool.

 *

 * Limit the number of areas to the maximum possible number of areas in

 * a memory pool of the given size.

 *

 * Return: Maximum possible number of areas.

 */

static unsigned int limit_nareas(unsigned int nareas, unsigned long nslots)

{

	if (nslots < nareas * IO_TLB_SEGSIZE)

		return nslots / IO_TLB_SEGSIZE;

	return nareas;

}



static int __init

setup_io_tlb_npages(char *str)

{
@@ -290,6 +314,7 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, 
{

	struct io_tlb_mem *mem = &io_tlb_default_mem;

	unsigned long nslabs;

	unsigned int nareas;

	size_t alloc_size;

	void *tlb;
@@ -298,18 +323,16 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, 
	if (swiotlb_force_disable)

		return;



	/*

	 * default_nslabs maybe changed when adjust area number.

	 * So allocate bounce buffer after adjusting area number.

	 */

	if (!default_nareas)

		swiotlb_adjust_nareas(num_possible_cpus());



	nslabs = default_nslabs;

	nareas = limit_nareas(default_nareas, nslabs);

	while ((tlb = swiotlb_memblock_alloc(nslabs, flags, remap)) == NULL) {

		if (nslabs <= IO_TLB_MIN_SLABS)

			return;

		nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE);

		nareas = limit_nareas(nareas, nslabs);

	}



	if (default_nslabs != nslabs) {
@@ -355,6 +378,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask, 
{

	struct io_tlb_mem *mem = &io_tlb_default_mem;

	unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE);

	unsigned int nareas;

	unsigned char *vstart = NULL;

	unsigned int order, area_order;

	bool retried = false;
@@ -363,6 +387,9 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask, 
	if (swiotlb_force_disable)

		return 0;



	if (!default_nareas)

		swiotlb_adjust_nareas(num_possible_cpus());



retry:

	order = get_order(nslabs << IO_TLB_SHIFT);

	nslabs = SLABS_PER_PAGE << order;
@@ -397,11 +424,8 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask, 
			(PAGE_SIZE << order) >> 20);

	}



	if (!default_nareas)

		swiotlb_adjust_nareas(num_possible_cpus());



	area_order = get_order(array_size(sizeof(*mem->areas),

		default_nareas));

	nareas = limit_nareas(default_nareas, nslabs);

	area_order = get_order(array_size(sizeof(*mem->areas), nareas));

	mem->areas = (struct io_tlb_area *)

		__get_free_pages(GFP_KERNEL | __GFP_ZERO, area_order);

	if (!mem->areas)
@@ -415,7 +439,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask, 
	set_memory_decrypted((unsigned long)vstart,

			     (nslabs << IO_TLB_SHIFT) >> PAGE_SHIFT);

	swiotlb_init_io_tlb_mem(mem, virt_to_phys(vstart), nslabs, 0, true,

				default_nareas);

				nareas);



	swiotlb_print_info();

	return 0;