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dma: compile-out DMA sync op calls when not used

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Some platforms do have DMA, but DMA there is always direct and coherent.
Currently, even on such platforms DMA sync operations are compiled and
called.
Add a new hidden Kconfig symbol, DMA_NEED_SYNC, and set it only when
either sync operations are needed or there is DMA ops or swiotlb
or DMA debug is enabled. Compile global dma_sync_*() and dma_need_sync()
only when it's set, otherwise provide empty inline stubs.
The change allows for future optimizations of DMA sync calls depending
on runtime conditions.

Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Alexander Lobakin 2024-05-07 13:20:20 +02:00 committed by Christoph Hellwig
parent 2650073f1b
commit fe7514b149
3 changed files with 50 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
include/linux/dma-mapping.h
View File

@ -117,14 +117,6 @@ dma_addr_t dma_map_resource(struct device *dev, phys_addr_t phys_addr,
size_t size, enum dma_data_direction dir, unsigned long attrs);
void dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
enum dma_data_direction dir, unsigned long attrs);
void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
enum dma_data_direction dir);
void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir);
void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir);
void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir);
void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
gfp_t flag, unsigned long attrs);
void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
@ -147,7 +139,6 @@ u64 dma_get_required_mask(struct device *dev);
bool dma_addressing_limited(struct device *dev);
size_t dma_max_mapping_size(struct device *dev);
size_t dma_opt_mapping_size(struct device *dev);
bool dma_need_sync(struct device *dev, dma_addr_t dma_addr);
unsigned long dma_get_merge_boundary(struct device *dev);
struct sg_table *dma_alloc_noncontiguous(struct device *dev, size_t size,
enum dma_data_direction dir, gfp_t gfp, unsigned long attrs);
@ -195,22 +186,6 @@ static inline void dma_unmap_resource(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
}
static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir)
{
}
static inline void dma_sync_single_for_device(struct device *dev,
dma_addr_t addr, size_t size, enum dma_data_direction dir)
{
}
static inline void dma_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sg, int nelems, enum dma_data_direction dir)
{
}
static inline void dma_sync_sg_for_device(struct device *dev,
struct scatterlist *sg, int nelems, enum dma_data_direction dir)
{
}
static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
return -ENOMEM;
@ -277,10 +252,6 @@ static inline size_t dma_opt_mapping_size(struct device *dev)
{
return 0;
}
static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
{
return false;
}
static inline unsigned long dma_get_merge_boundary(struct device *dev)
{
return 0;
@ -310,6 +281,39 @@ static inline int dma_mmap_noncontiguous(struct device *dev,
}
#endif /* CONFIG_HAS_DMA */
#if defined(CONFIG_HAS_DMA) && defined(CONFIG_DMA_NEED_SYNC)
void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
enum dma_data_direction dir);
void dma_sync_single_for_device(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir);
void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir);
void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir);
bool dma_need_sync(struct device *dev, dma_addr_t dma_addr);
#else /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */
static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir)
{
}
static inline void dma_sync_single_for_device(struct device *dev,
dma_addr_t addr, size_t size, enum dma_data_direction dir)
{
}
static inline void dma_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sg, int nelems, enum dma_data_direction dir)
{
}
static inline void dma_sync_sg_for_device(struct device *dev,
struct scatterlist *sg, int nelems, enum dma_data_direction dir)
{
}
static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
{
return false;
}
#endif /* !CONFIG_HAS_DMA || !CONFIG_DMA_NEED_SYNC */
struct page *dma_alloc_pages(struct device *dev, size_t size,
dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp);
void dma_free_pages(struct device *dev, size_t size, struct page *page,

5
kernel/dma/Kconfig
View File

@ -107,6 +107,11 @@ config DMA_BOUNCE_UNALIGNED_KMALLOC
bool
depends on SWIOTLB
config DMA_NEED_SYNC
def_bool ARCH_HAS_SYNC_DMA_FOR_DEVICE || ARCH_HAS_SYNC_DMA_FOR_CPU || \
ARCH_HAS_SYNC_DMA_FOR_CPU_ALL || DMA_API_DEBUG || DMA_OPS || \
SWIOTLB
config DMA_RESTRICTED_POOL
bool "DMA Restricted Pool"
depends on OF && OF_RESERVED_MEM && SWIOTLB

22
kernel/dma/mapping.c
View File

@ -329,6 +329,7 @@ void dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
}
EXPORT_SYMBOL(dma_unmap_resource);
#ifdef CONFIG_DMA_NEED_SYNC
void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, size_t size,
enum dma_data_direction dir)
{
@ -385,6 +386,17 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
}
EXPORT_SYMBOL(dma_sync_sg_for_device);
bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
if (dma_map_direct(dev, ops))
return dma_direct_need_sync(dev, dma_addr);
return ops->sync_single_for_cpu || ops->sync_single_for_device;
}
EXPORT_SYMBOL_GPL(dma_need_sync);
#endif /* CONFIG_DMA_NEED_SYNC */
/*
* The whole dma_get_sgtable() idea is fundamentally unsafe - it seems
* that the intention is to allow exporting memory allocated via the
@ -841,16 +853,6 @@ size_t dma_opt_mapping_size(struct device *dev)
}
EXPORT_SYMBOL_GPL(dma_opt_mapping_size);
bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
if (dma_map_direct(dev, ops))
return dma_direct_need_sync(dev, dma_addr);
return ops->sync_single_for_cpu || ops->sync_single_for_device;
}
EXPORT_SYMBOL_GPL(dma_need_sync);
unsigned long dma_get_merge_boundary(struct device *dev)
{
const struct dma_map_ops *ops = get_dma_ops(dev);