Commit c03e9c42 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'dma-mapping-6.19-2026-01-20' of... 

Merge tag 'dma-mapping-6.19-2026-01-20' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux

Pull dma-mapping fixes from Marek Szyprowski:

 - minor fixes for the corner cases of the SWIOTLB pool management
   (Robin Murphy)

* tag 'dma-mapping-6.19-2026-01-20' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
  dma/pool: Avoid allocating redundant pools
  mm_zone: Generalise has_managed_dma()
  dma/pool: Improve pool lookup
parents 8f7537ef c6ccd098

include/linux/mmzone.h

+5 −4
Original line number Diff line number Diff line
@@ -1648,14 +1648,15 @@ static inline int is_highmem(const struct zone *zone) 
	return is_highmem_idx(zone_idx(zone));

}



#ifdef CONFIG_ZONE_DMA

bool has_managed_dma(void);

#else

bool has_managed_zone(enum zone_type zone);

static inline bool has_managed_dma(void)

{

#ifdef CONFIG_ZONE_DMA

	return has_managed_zone(ZONE_DMA);

#else

	return false;

}

#endif

}





#ifndef CONFIG_NUMA

kernel/dma/pool.c

+18 −9
Original line number Diff line number Diff line
@@ -184,6 +184,12 @@ static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size, 
	return pool;

}



#ifdef CONFIG_ZONE_DMA32

#define has_managed_dma32 has_managed_zone(ZONE_DMA32)

#else

#define has_managed_dma32 false

#endif



static int __init dma_atomic_pool_init(void)

{

	int ret = 0;
@@ -199,17 +205,20 @@ static int __init dma_atomic_pool_init(void) 
	}

	INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);



	/* All memory might be in the DMA zone(s) to begin with */

	if (has_managed_zone(ZONE_NORMAL)) {

		atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,

						    GFP_KERNEL);

		if (!atomic_pool_kernel)

			ret = -ENOMEM;

	}

	if (has_managed_dma()) {

		atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,

						GFP_KERNEL | GFP_DMA);

		if (!atomic_pool_dma)

			ret = -ENOMEM;

	}

	if (IS_ENABLED(CONFIG_ZONE_DMA32)) {

	if (has_managed_dma32) {

		atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,

						GFP_KERNEL | GFP_DMA32);

		if (!atomic_pool_dma32)
@@ -224,11 +233,11 @@ postcore_initcall(dma_atomic_pool_init); 
static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp)

{

	if (prev == NULL) {

		if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))

			return atomic_pool_dma32;

		if (atomic_pool_dma && (gfp & GFP_DMA))

			return atomic_pool_dma;

		return atomic_pool_kernel;

		if (gfp & GFP_DMA)

			return atomic_pool_dma ?: atomic_pool_dma32 ?: atomic_pool_kernel;

		if (gfp & GFP_DMA32)

			return atomic_pool_dma32 ?: atomic_pool_dma ?: atomic_pool_kernel;

		return atomic_pool_kernel ?: atomic_pool_dma32 ?: atomic_pool_dma;

	}

	if (prev == atomic_pool_kernel)

		return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma;

mm/page_alloc.c

+2 −6
Original line number Diff line number Diff line
@@ -7457,20 +7457,16 @@ bool put_page_back_buddy(struct page *page) 
}

#endif



#ifdef CONFIG_ZONE_DMA

bool has_managed_dma(void)

bool has_managed_zone(enum zone_type zone)

{

	struct pglist_data *pgdat;



	for_each_online_pgdat(pgdat) {

		struct zone *zone = &pgdat->node_zones[ZONE_DMA];



		if (managed_zone(zone))

		if (managed_zone(&pgdat->node_zones[zone]))

			return true;

	}

	return false;

}

#endif /* CONFIG_ZONE_DMA */



#ifdef CONFIG_UNACCEPTED_MEMORY