1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
/* Copyright (c) 2026, NVIDIA CORPORATION & AFFILIATES. */
#ifndef _RDMA_ITER_H_
#define _RDMA_ITER_H_
#include <linux/scatterlist.h>
#include <rdma/ib_umem.h>
/**
* IB block DMA iterator
*
* Iterates the DMA-mapped SGL in contiguous memory blocks aligned
* to a HW supported page size.
*/
struct ib_block_iter {
/* internal states */
struct scatterlist *__sg; /* sg holding the current aligned block */
dma_addr_t __dma_addr; /* unaligned DMA address of this block */
size_t __sg_numblocks; /* ib_umem_num_dma_blocks() */
unsigned int __sg_nents; /* number of SG entries */
unsigned int __sg_advance; /* number of bytes to advance in sg in next step */
unsigned int __pg_bit; /* alignment of current block */
};
void __rdma_block_iter_start(struct ib_block_iter *biter,
struct scatterlist *sglist,
unsigned int nents,
unsigned long pgsz);
bool __rdma_block_iter_next(struct ib_block_iter *biter);
/**
* rdma_block_iter_dma_address - get the aligned dma address of the current
* block held by the block iterator.
* @biter: block iterator holding the memory block
*/
static inline dma_addr_t
rdma_block_iter_dma_address(struct ib_block_iter *biter)
{
return biter->__dma_addr & ~(BIT_ULL(biter->__pg_bit) - 1);
}
/**
* rdma_for_each_block - iterate over contiguous memory blocks of the sg list
* @sglist: sglist to iterate over
* @biter: block iterator holding the memory block
* @nents: maximum number of sg entries to iterate over
* @pgsz: best HW supported page size to use
*
* Callers may use rdma_block_iter_dma_address() to get each
* blocks aligned DMA address.
*/
#define rdma_for_each_block(sglist, biter, nents, pgsz) \
for (__rdma_block_iter_start(biter, sglist, nents, \
pgsz); \
__rdma_block_iter_next(biter);)
static inline void __rdma_umem_block_iter_start(struct ib_block_iter *biter,
struct ib_umem *umem,
unsigned long pgsz)
{
__rdma_block_iter_start(biter, umem->sgt_append.sgt.sgl,
umem->sgt_append.sgt.nents, pgsz);
biter->__sg_advance = ib_umem_offset(umem) & ~(pgsz - 1);
biter->__sg_numblocks = ib_umem_num_dma_blocks(umem, pgsz);
}
static inline bool __rdma_umem_block_iter_next(struct ib_block_iter *biter)
{
return __rdma_block_iter_next(biter) && biter->__sg_numblocks--;
}
/**
* rdma_umem_for_each_dma_block - iterate over contiguous DMA blocks of the umem
* @umem: umem to iterate over
* @pgsz: Page size to split the list into
*
* pgsz must be <= PAGE_SIZE or computed by ib_umem_find_best_pgsz(). The
* returned DMA blocks will be aligned to pgsz and span the range:
* ALIGN_DOWN(umem->address, pgsz) to ALIGN(umem->address + umem->length, pgsz)
*
* Performs exactly ib_umem_num_dma_blocks() iterations.
*/
#define rdma_umem_for_each_dma_block(umem, biter, pgsz) \
for (__rdma_umem_block_iter_start(biter, umem, pgsz); \
__rdma_umem_block_iter_next(biter);)
#endif /* _RDMA_ITER_H_ */
|
