linux-stable/include/linux/dma-debug.h
Linus Torvalds 5848dc5b1b dma-debug: remove debug_dma_assert_idle() function
This remoes the code from the COW path to call debug_dma_assert_idle(),
which was added many years ago.

Google shows that it hasn't caught anything in the 6+ years we've had it
apart from a false positive, and Hugh just noticed how it had a very
unfortunate spinlock serialization in the COW path.

He fixed that issue the previous commit (a85ffd59bd: "dma-debug: fix
debug_dma_assert_idle(), use rcu_read_lock()"), but let's see if anybody
even notices when we remove this function entirely.

NOTE! We keep the dma tracking infrastructure that was added by the
commit that introduced it.  Partly to make it easier to resurrect this
debug code if we ever deside to, and partly because that tracking by pfn
and offset looks quite reasonable.

The problem with this debug code was simply that it was expensive and
didn't seem worth it, not that it was wrong per se.

Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-14 15:22:43 -07:00

160 lines
4.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2008 Advanced Micro Devices, Inc.
*
* Author: Joerg Roedel <joerg.roedel@amd.com>
*/
#ifndef __DMA_DEBUG_H
#define __DMA_DEBUG_H
#include <linux/types.h>
struct device;
struct scatterlist;
struct bus_type;
#ifdef CONFIG_DMA_API_DEBUG
extern void dma_debug_add_bus(struct bus_type *bus);
extern void debug_dma_map_single(struct device *dev, const void *addr,
unsigned long len);
extern void debug_dma_map_page(struct device *dev, struct page *page,
size_t offset, size_t size,
int direction, dma_addr_t dma_addr);
extern void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr);
extern void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, int direction);
extern void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
int nents, int mapped_ents, int direction);
extern void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
int nelems, int dir);
extern void debug_dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t dma_addr, void *virt);
extern void debug_dma_free_coherent(struct device *dev, size_t size,
void *virt, dma_addr_t addr);
extern void debug_dma_map_resource(struct device *dev, phys_addr_t addr,
size_t size, int direction,
dma_addr_t dma_addr);
extern void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
size_t size, int direction);
extern void debug_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size,
int direction);
extern void debug_dma_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle,
size_t size, int direction);
extern void debug_dma_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sg,
int nelems, int direction);
extern void debug_dma_sync_sg_for_device(struct device *dev,
struct scatterlist *sg,
int nelems, int direction);
extern void debug_dma_dump_mappings(struct device *dev);
#else /* CONFIG_DMA_API_DEBUG */
static inline void dma_debug_add_bus(struct bus_type *bus)
{
}
static inline void debug_dma_map_single(struct device *dev, const void *addr,
unsigned long len)
{
}
static inline void debug_dma_map_page(struct device *dev, struct page *page,
size_t offset, size_t size,
int direction, dma_addr_t dma_addr)
{
}
static inline void debug_dma_mapping_error(struct device *dev,
dma_addr_t dma_addr)
{
}
static inline void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, int direction)
{
}
static inline void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
int nents, int mapped_ents, int direction)
{
}
static inline void debug_dma_unmap_sg(struct device *dev,
struct scatterlist *sglist,
int nelems, int dir)
{
}
static inline void debug_dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t dma_addr, void *virt)
{
}
static inline void debug_dma_free_coherent(struct device *dev, size_t size,
void *virt, dma_addr_t addr)
{
}
static inline void debug_dma_map_resource(struct device *dev, phys_addr_t addr,
size_t size, int direction,
dma_addr_t dma_addr)
{
}
static inline void debug_dma_unmap_resource(struct device *dev,
dma_addr_t dma_addr, size_t size,
int direction)
{
}
static inline void debug_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle,
size_t size, int direction)
{
}
static inline void debug_dma_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle,
size_t size, int direction)
{
}
static inline void debug_dma_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sg,
int nelems, int direction)
{
}
static inline void debug_dma_sync_sg_for_device(struct device *dev,
struct scatterlist *sg,
int nelems, int direction)
{
}
static inline void debug_dma_dump_mappings(struct device *dev)
{
}
#endif /* CONFIG_DMA_API_DEBUG */
#endif /* __DMA_DEBUG_H */