1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun * Copyright (C) Nelson Integration, LLC 2016
3*4882a593Smuzhiyun * Author: Eric Nelson<eric@nelint.com>
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * SPDX-License-Identifier: GPL-2.0+
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun */
8*4882a593Smuzhiyun #include <config.h>
9*4882a593Smuzhiyun #include <common.h>
10*4882a593Smuzhiyun #include <malloc.h>
11*4882a593Smuzhiyun #include <part.h>
12*4882a593Smuzhiyun #include <linux/ctype.h>
13*4882a593Smuzhiyun #include <linux/list.h>
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun struct block_cache_node {
16*4882a593Smuzhiyun struct list_head lh;
17*4882a593Smuzhiyun int iftype;
18*4882a593Smuzhiyun int devnum;
19*4882a593Smuzhiyun lbaint_t start;
20*4882a593Smuzhiyun lbaint_t blkcnt;
21*4882a593Smuzhiyun unsigned long blksz;
22*4882a593Smuzhiyun char *cache;
23*4882a593Smuzhiyun };
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun static LIST_HEAD(block_cache);
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun static struct block_cache_stats _stats = {
28*4882a593Smuzhiyun .max_blocks_per_entry = 2,
29*4882a593Smuzhiyun .max_entries = 32
30*4882a593Smuzhiyun };
31*4882a593Smuzhiyun
cache_find(int iftype,int devnum,lbaint_t start,lbaint_t blkcnt,unsigned long blksz)32*4882a593Smuzhiyun static struct block_cache_node *cache_find(int iftype, int devnum,
33*4882a593Smuzhiyun lbaint_t start, lbaint_t blkcnt,
34*4882a593Smuzhiyun unsigned long blksz)
35*4882a593Smuzhiyun {
36*4882a593Smuzhiyun struct block_cache_node *node;
37*4882a593Smuzhiyun
38*4882a593Smuzhiyun list_for_each_entry(node, &block_cache, lh)
39*4882a593Smuzhiyun if ((node->iftype == iftype) &&
40*4882a593Smuzhiyun (node->devnum == devnum) &&
41*4882a593Smuzhiyun (node->blksz == blksz) &&
42*4882a593Smuzhiyun (node->start <= start) &&
43*4882a593Smuzhiyun (node->start + node->blkcnt >= start + blkcnt)) {
44*4882a593Smuzhiyun if (block_cache.next != &node->lh) {
45*4882a593Smuzhiyun /* maintain MRU ordering */
46*4882a593Smuzhiyun list_del(&node->lh);
47*4882a593Smuzhiyun list_add(&node->lh, &block_cache);
48*4882a593Smuzhiyun }
49*4882a593Smuzhiyun return node;
50*4882a593Smuzhiyun }
51*4882a593Smuzhiyun return 0;
52*4882a593Smuzhiyun }
53*4882a593Smuzhiyun
blkcache_read(int iftype,int devnum,lbaint_t start,lbaint_t blkcnt,unsigned long blksz,void * buffer)54*4882a593Smuzhiyun int blkcache_read(int iftype, int devnum,
55*4882a593Smuzhiyun lbaint_t start, lbaint_t blkcnt,
56*4882a593Smuzhiyun unsigned long blksz, void *buffer)
57*4882a593Smuzhiyun {
58*4882a593Smuzhiyun struct block_cache_node *node = cache_find(iftype, devnum, start,
59*4882a593Smuzhiyun blkcnt, blksz);
60*4882a593Smuzhiyun if (node) {
61*4882a593Smuzhiyun const char *src = node->cache + (start - node->start) * blksz;
62*4882a593Smuzhiyun memcpy(buffer, src, blksz * blkcnt);
63*4882a593Smuzhiyun debug("hit: start " LBAF ", count " LBAFU "\n",
64*4882a593Smuzhiyun start, blkcnt);
65*4882a593Smuzhiyun ++_stats.hits;
66*4882a593Smuzhiyun return 1;
67*4882a593Smuzhiyun }
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun debug("miss: start " LBAF ", count " LBAFU "\n",
70*4882a593Smuzhiyun start, blkcnt);
71*4882a593Smuzhiyun ++_stats.misses;
72*4882a593Smuzhiyun return 0;
73*4882a593Smuzhiyun }
74*4882a593Smuzhiyun
blkcache_fill(int iftype,int devnum,lbaint_t start,lbaint_t blkcnt,unsigned long blksz,void const * buffer)75*4882a593Smuzhiyun void blkcache_fill(int iftype, int devnum,
76*4882a593Smuzhiyun lbaint_t start, lbaint_t blkcnt,
77*4882a593Smuzhiyun unsigned long blksz, void const *buffer)
78*4882a593Smuzhiyun {
79*4882a593Smuzhiyun lbaint_t bytes;
80*4882a593Smuzhiyun struct block_cache_node *node;
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun /* don't cache big stuff */
83*4882a593Smuzhiyun if (blkcnt > _stats.max_blocks_per_entry)
84*4882a593Smuzhiyun return;
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun if (_stats.max_entries == 0)
87*4882a593Smuzhiyun return;
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun bytes = blksz * blkcnt;
90*4882a593Smuzhiyun if (_stats.max_entries <= _stats.entries) {
91*4882a593Smuzhiyun /* pop LRU */
92*4882a593Smuzhiyun node = (struct block_cache_node *)block_cache.prev;
93*4882a593Smuzhiyun list_del(&node->lh);
94*4882a593Smuzhiyun _stats.entries--;
95*4882a593Smuzhiyun debug("drop: start " LBAF ", count " LBAFU "\n",
96*4882a593Smuzhiyun node->start, node->blkcnt);
97*4882a593Smuzhiyun if (node->blkcnt * node->blksz < bytes) {
98*4882a593Smuzhiyun free(node->cache);
99*4882a593Smuzhiyun node->cache = 0;
100*4882a593Smuzhiyun }
101*4882a593Smuzhiyun } else {
102*4882a593Smuzhiyun node = malloc(sizeof(*node));
103*4882a593Smuzhiyun if (!node)
104*4882a593Smuzhiyun return;
105*4882a593Smuzhiyun node->cache = 0;
106*4882a593Smuzhiyun }
107*4882a593Smuzhiyun
108*4882a593Smuzhiyun if (!node->cache) {
109*4882a593Smuzhiyun node->cache = malloc(bytes);
110*4882a593Smuzhiyun if (!node->cache) {
111*4882a593Smuzhiyun free(node);
112*4882a593Smuzhiyun return;
113*4882a593Smuzhiyun }
114*4882a593Smuzhiyun }
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun debug("fill: start " LBAF ", count " LBAFU "\n",
117*4882a593Smuzhiyun start, blkcnt);
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun node->iftype = iftype;
120*4882a593Smuzhiyun node->devnum = devnum;
121*4882a593Smuzhiyun node->start = start;
122*4882a593Smuzhiyun node->blkcnt = blkcnt;
123*4882a593Smuzhiyun node->blksz = blksz;
124*4882a593Smuzhiyun memcpy(node->cache, buffer, bytes);
125*4882a593Smuzhiyun list_add(&node->lh, &block_cache);
126*4882a593Smuzhiyun _stats.entries++;
127*4882a593Smuzhiyun }
128*4882a593Smuzhiyun
blkcache_invalidate(int iftype,int devnum)129*4882a593Smuzhiyun void blkcache_invalidate(int iftype, int devnum)
130*4882a593Smuzhiyun {
131*4882a593Smuzhiyun struct list_head *entry, *n;
132*4882a593Smuzhiyun struct block_cache_node *node;
133*4882a593Smuzhiyun
134*4882a593Smuzhiyun list_for_each_safe(entry, n, &block_cache) {
135*4882a593Smuzhiyun node = (struct block_cache_node *)entry;
136*4882a593Smuzhiyun if ((node->iftype == iftype) &&
137*4882a593Smuzhiyun (node->devnum == devnum)) {
138*4882a593Smuzhiyun list_del(entry);
139*4882a593Smuzhiyun free(node->cache);
140*4882a593Smuzhiyun free(node);
141*4882a593Smuzhiyun --_stats.entries;
142*4882a593Smuzhiyun }
143*4882a593Smuzhiyun }
144*4882a593Smuzhiyun }
145*4882a593Smuzhiyun
blkcache_configure(unsigned blocks,unsigned entries)146*4882a593Smuzhiyun void blkcache_configure(unsigned blocks, unsigned entries)
147*4882a593Smuzhiyun {
148*4882a593Smuzhiyun struct block_cache_node *node;
149*4882a593Smuzhiyun if ((blocks != _stats.max_blocks_per_entry) ||
150*4882a593Smuzhiyun (entries != _stats.max_entries)) {
151*4882a593Smuzhiyun /* invalidate cache */
152*4882a593Smuzhiyun while (!list_empty(&block_cache)) {
153*4882a593Smuzhiyun node = (struct block_cache_node *)block_cache.next;
154*4882a593Smuzhiyun list_del(&node->lh);
155*4882a593Smuzhiyun free(node->cache);
156*4882a593Smuzhiyun free(node);
157*4882a593Smuzhiyun }
158*4882a593Smuzhiyun _stats.entries = 0;
159*4882a593Smuzhiyun }
160*4882a593Smuzhiyun
161*4882a593Smuzhiyun _stats.max_blocks_per_entry = blocks;
162*4882a593Smuzhiyun _stats.max_entries = entries;
163*4882a593Smuzhiyun
164*4882a593Smuzhiyun _stats.hits = 0;
165*4882a593Smuzhiyun _stats.misses = 0;
166*4882a593Smuzhiyun }
167*4882a593Smuzhiyun
blkcache_stats(struct block_cache_stats * stats)168*4882a593Smuzhiyun void blkcache_stats(struct block_cache_stats *stats)
169*4882a593Smuzhiyun {
170*4882a593Smuzhiyun memcpy(stats, &_stats, sizeof(*stats));
171*4882a593Smuzhiyun _stats.hits = 0;
172*4882a593Smuzhiyun _stats.misses = 0;
173*4882a593Smuzhiyun }
174