include/linux/swiotlb.h

Source file repositories/reference/linux-study-clean/include/linux/swiotlb.h

File Facts

System
Linux kernel
Corpus path
include/linux/swiotlb.h
Extension
.h
Size
9312 bytes
Lines
309
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct io_tlb_pool {
	phys_addr_t start;
	phys_addr_t end;
	void *vaddr;
	unsigned long nslabs;
	bool late_alloc;
	unsigned int nareas;
	unsigned int area_nslabs;
	struct io_tlb_area *areas;
	struct io_tlb_slot *slots;
#ifdef CONFIG_SWIOTLB_DYNAMIC
	struct list_head node;
	struct rcu_head rcu;
	bool transient;
#endif
};

/**
 * struct io_tlb_mem - Software IO TLB allocator
 * @defpool:	Default (initial) IO TLB memory pool descriptor.
 * @pool:	IO TLB memory pool descriptor (if not dynamic).
 * @nslabs:	Total number of IO TLB slabs in all pools.
 * @debugfs:	The dentry to debugfs.
 * @force_bounce: %true if swiotlb bouncing is forced
 * @for_alloc:  %true if the pool is used for memory allocation
 * @can_grow:	%true if more pools can be allocated dynamically.
 * @phys_limit:	Maximum allowed physical address.
 * @lock:	Lock to synchronize changes to the list.
 * @pools:	List of IO TLB memory pool descriptors (if dynamic).
 * @dyn_alloc:	Dynamic IO TLB pool allocation work.
 * @total_used:	The total number of slots in the pool that are currently used
 *		across all areas. Used only for calculating used_hiwater in
 *		debugfs.
 * @used_hiwater: The high water mark for total_used.  Used only for reporting
 *		in debugfs.
 * @transient_nslabs: The total number of slots in all transient pools that
 *		are currently used across all areas.
 */
struct io_tlb_mem {
	struct io_tlb_pool defpool;
	unsigned long nslabs;
	struct dentry *debugfs;
	bool force_bounce;
	bool for_alloc;
#ifdef CONFIG_SWIOTLB_DYNAMIC
	bool can_grow;
	u64 phys_limit;
	spinlock_t lock;
	struct list_head pools;
	struct work_struct dyn_alloc;
#endif
#ifdef CONFIG_DEBUG_FS
	atomic_long_t total_used;
	atomic_long_t used_hiwater;
	atomic_long_t transient_nslabs;
#endif
};

struct io_tlb_pool *__swiotlb_find_pool(struct device *dev, phys_addr_t paddr);

/**
 * swiotlb_find_pool() - find swiotlb pool to which a physical address belongs
 * @dev:        Device which has mapped the buffer.
 * @paddr:      Physical address within the DMA buffer.
 *
 * Find the swiotlb pool that @paddr points into.
 *
 * Return:
 * * pool address if @paddr points into a bounce buffer
 * * NULL if @paddr does not point into a bounce buffer. As such, this function
 *   can be used to determine if @paddr denotes a swiotlb bounce buffer.
 */
static inline struct io_tlb_pool *swiotlb_find_pool(struct device *dev,
		phys_addr_t paddr)
{
	struct io_tlb_mem *mem = dev->dma_io_tlb_mem;

	if (!mem)
		return NULL;

#ifdef CONFIG_SWIOTLB_DYNAMIC
	/*
	 * All SWIOTLB buffer addresses must have been returned by
	 * swiotlb_tbl_map_single() and passed to a device driver.
	 * If a SWIOTLB address is checked on another CPU, then it was
	 * presumably loaded by the device driver from an unspecified private
	 * data structure. Make sure that this load is ordered before reading
	 * dev->dma_uses_io_tlb here and mem->pools in __swiotlb_find_pool().
	 *
	 * This barrier pairs with smp_mb() in swiotlb_find_slots().

Annotation

Implementation Notes