xref: /openbmc/linux/include/rdma/rdmavt_mr.h (revision d9fd5a71)
1 /* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
2 /*
3  * Copyright(c) 2016 Intel Corporation.
4  */
5 
6 #ifndef DEF_RDMAVT_INCMR_H
7 #define DEF_RDMAVT_INCMR_H
8 
9 /*
10  * For Memory Regions. This stuff should probably be moved into rdmavt/mr.h once
11  * drivers no longer need access to the MR directly.
12  */
13 #include <linux/percpu-refcount.h>
14 
15 /*
16  * A segment is a linear region of low physical memory.
17  * Used by the verbs layer.
18  */
19 struct rvt_seg {
20 	void *vaddr;
21 	size_t length;
22 };
23 
24 /* The number of rvt_segs that fit in a page. */
25 #define RVT_SEGSZ     (PAGE_SIZE / sizeof(struct rvt_seg))
26 
27 struct rvt_segarray {
28 	struct rvt_seg segs[RVT_SEGSZ];
29 };
30 
31 struct rvt_mregion {
32 	struct ib_pd *pd;       /* shares refcnt of ibmr.pd */
33 	u64 user_base;          /* User's address for this region */
34 	u64 iova;               /* IB start address of this region */
35 	size_t length;
36 	u32 lkey;
37 	u32 offset;             /* offset (bytes) to start of region */
38 	int access_flags;
39 	u32 max_segs;           /* number of rvt_segs in all the arrays */
40 	u32 mapsz;              /* size of the map array */
41 	atomic_t lkey_invalid;	/* true if current lkey is invalid */
42 	u8  page_shift;         /* 0 - non unform/non powerof2 sizes */
43 	u8  lkey_published;     /* in global table */
44 	struct percpu_ref refcount;
45 	struct completion comp; /* complete when refcount goes to zero */
46 	struct rvt_segarray *map[];    /* the segments */
47 };
48 
49 #define RVT_MAX_LKEY_TABLE_BITS 23
50 
51 struct rvt_lkey_table {
52 	/* read mostly fields */
53 	u32 max;                /* size of the table */
54 	u32 shift;              /* lkey/rkey shift */
55 	struct rvt_mregion __rcu **table;
56 	/* writeable fields */
57 	/* protect changes in this struct */
58 	spinlock_t lock ____cacheline_aligned_in_smp;
59 	u32 next;               /* next unused index (speeds search) */
60 	u32 gen;                /* generation count */
61 };
62 
63 /*
64  * These keep track of the copy progress within a memory region.
65  * Used by the verbs layer.
66  */
67 struct rvt_sge {
68 	struct rvt_mregion *mr;
69 	void *vaddr;            /* kernel virtual address of segment */
70 	u32 sge_length;         /* length of the SGE */
71 	u32 length;             /* remaining length of the segment */
72 	u16 m;                  /* current index: mr->map[m] */
73 	u16 n;                  /* current index: mr->map[m]->segs[n] */
74 };
75 
76 struct rvt_sge_state {
77 	struct rvt_sge *sg_list;      /* next SGE to be used if any */
78 	struct rvt_sge sge;   /* progress state for the current SGE */
79 	u32 total_len;
80 	u8 num_sge;
81 };
82 
83 static inline void rvt_put_mr(struct rvt_mregion *mr)
84 {
85 	percpu_ref_put(&mr->refcount);
86 }
87 
88 static inline void rvt_get_mr(struct rvt_mregion *mr)
89 {
90 	percpu_ref_get(&mr->refcount);
91 }
92 
93 static inline void rvt_put_ss(struct rvt_sge_state *ss)
94 {
95 	while (ss->num_sge) {
96 		rvt_put_mr(ss->sge.mr);
97 		if (--ss->num_sge)
98 			ss->sge = *ss->sg_list++;
99 	}
100 }
101 
102 static inline u32 rvt_get_sge_length(struct rvt_sge *sge, u32 length)
103 {
104 	u32 len = sge->length;
105 
106 	if (len > length)
107 		len = length;
108 	if (len > sge->sge_length)
109 		len = sge->sge_length;
110 
111 	return len;
112 }
113 
114 static inline void rvt_update_sge(struct rvt_sge_state *ss, u32 length,
115 				  bool release)
116 {
117 	struct rvt_sge *sge = &ss->sge;
118 
119 	sge->vaddr += length;
120 	sge->length -= length;
121 	sge->sge_length -= length;
122 	if (sge->sge_length == 0) {
123 		if (release)
124 			rvt_put_mr(sge->mr);
125 		if (--ss->num_sge)
126 			*sge = *ss->sg_list++;
127 	} else if (sge->length == 0 && sge->mr->lkey) {
128 		if (++sge->n >= RVT_SEGSZ) {
129 			if (++sge->m >= sge->mr->mapsz)
130 				return;
131 			sge->n = 0;
132 		}
133 		sge->vaddr = sge->mr->map[sge->m]->segs[sge->n].vaddr;
134 		sge->length = sge->mr->map[sge->m]->segs[sge->n].length;
135 	}
136 }
137 
138 static inline void rvt_skip_sge(struct rvt_sge_state *ss, u32 length,
139 				bool release)
140 {
141 	struct rvt_sge *sge = &ss->sge;
142 
143 	while (length) {
144 		u32 len = rvt_get_sge_length(sge, length);
145 
146 		WARN_ON_ONCE(len == 0);
147 		rvt_update_sge(ss, len, release);
148 		length -= len;
149 	}
150 }
151 
152 bool rvt_ss_has_lkey(struct rvt_sge_state *ss, u32 lkey);
153 bool rvt_mr_has_lkey(struct rvt_mregion *mr, u32 lkey);
154 
155 #endif          /* DEF_RDMAVT_INCMRH */
156