1 // SPDX-License-Identifier: GPL-2.0
2
3 #include "kublk.h"
4
5 #define NR_STRIPE MAX_BACK_FILES
6
7 struct stripe_conf {
8 unsigned nr_files;
9 unsigned shift;
10 };
11
12 struct stripe {
13 loff_t start;
14 unsigned nr_sects;
15 int seq;
16
17 struct iovec *vec;
18 unsigned nr_vec;
19 unsigned cap;
20 };
21
22 struct stripe_array {
23 struct stripe s[NR_STRIPE];
24 unsigned nr;
25 struct iovec _vec[];
26 };
27
get_chunk_shift(const struct ublk_queue * q)28 static inline const struct stripe_conf *get_chunk_shift(const struct ublk_queue *q)
29 {
30 return (struct stripe_conf *)q->dev->private_data;
31 }
32
calculate_nr_vec(const struct stripe_conf * conf,const struct ublksrv_io_desc * iod)33 static inline unsigned calculate_nr_vec(const struct stripe_conf *conf,
34 const struct ublksrv_io_desc *iod)
35 {
36 const unsigned shift = conf->shift - 9;
37 const unsigned unit_sects = conf->nr_files << shift;
38 loff_t start = iod->start_sector;
39 loff_t end = start + iod->nr_sectors;
40
41 return (end / unit_sects) - (start / unit_sects) + 1;
42 }
43
alloc_stripe_array(const struct stripe_conf * conf,const struct ublksrv_io_desc * iod)44 static struct stripe_array *alloc_stripe_array(const struct stripe_conf *conf,
45 const struct ublksrv_io_desc *iod)
46 {
47 unsigned nr_vecs = calculate_nr_vec(conf, iod);
48 unsigned total = nr_vecs * conf->nr_files;
49 struct stripe_array *s;
50 int i;
51
52 s = malloc(sizeof(*s) + total * sizeof(struct iovec));
53
54 s->nr = 0;
55 for (i = 0; i < conf->nr_files; i++) {
56 struct stripe *t = &s->s[i];
57
58 t->nr_vec = 0;
59 t->vec = &s->_vec[i * nr_vecs];
60 t->nr_sects = 0;
61 t->cap = nr_vecs;
62 }
63
64 return s;
65 }
66
free_stripe_array(struct stripe_array * s)67 static void free_stripe_array(struct stripe_array *s)
68 {
69 free(s);
70 }
71
calculate_stripe_array(const struct stripe_conf * conf,const struct ublksrv_io_desc * iod,struct stripe_array * s)72 static void calculate_stripe_array(const struct stripe_conf *conf,
73 const struct ublksrv_io_desc *iod, struct stripe_array *s)
74 {
75 const unsigned shift = conf->shift - 9;
76 const unsigned chunk_sects = 1 << shift;
77 const unsigned unit_sects = conf->nr_files << shift;
78 off64_t start = iod->start_sector;
79 off64_t end = start + iod->nr_sectors;
80 unsigned long done = 0;
81 unsigned idx = 0;
82
83 while (start < end) {
84 unsigned nr_sects = chunk_sects - (start & (chunk_sects - 1));
85 loff_t unit_off = (start / unit_sects) * unit_sects;
86 unsigned seq = (start - unit_off) >> shift;
87 struct stripe *this = &s->s[idx];
88 loff_t stripe_off = (unit_off / conf->nr_files) +
89 (start & (chunk_sects - 1));
90
91 if (nr_sects > end - start)
92 nr_sects = end - start;
93 if (this->nr_sects == 0) {
94 this->nr_sects = nr_sects;
95 this->start = stripe_off;
96 this->seq = seq;
97 s->nr += 1;
98 } else {
99 assert(seq == this->seq);
100 assert(this->start + this->nr_sects == stripe_off);
101 this->nr_sects += nr_sects;
102 }
103
104 assert(this->nr_vec < this->cap);
105 this->vec[this->nr_vec].iov_base = (void *)(iod->addr + done);
106 this->vec[this->nr_vec++].iov_len = nr_sects << 9;
107
108 start += nr_sects;
109 done += nr_sects << 9;
110 idx = (idx + 1) % conf->nr_files;
111 }
112 }
113
stripe_to_uring_op(const struct ublksrv_io_desc * iod)114 static inline enum io_uring_op stripe_to_uring_op(const struct ublksrv_io_desc *iod)
115 {
116 unsigned ublk_op = ublksrv_get_op(iod);
117
118 if (ublk_op == UBLK_IO_OP_READ)
119 return IORING_OP_READV;
120 else if (ublk_op == UBLK_IO_OP_WRITE)
121 return IORING_OP_WRITEV;
122 assert(0);
123 }
124
stripe_queue_tgt_rw_io(struct ublk_queue * q,const struct ublksrv_io_desc * iod,int tag)125 static int stripe_queue_tgt_rw_io(struct ublk_queue *q, const struct ublksrv_io_desc *iod, int tag)
126 {
127 const struct stripe_conf *conf = get_chunk_shift(q);
128 enum io_uring_op op = stripe_to_uring_op(iod);
129 struct io_uring_sqe *sqe[NR_STRIPE];
130 struct stripe_array *s = alloc_stripe_array(conf, iod);
131 struct ublk_io *io = ublk_get_io(q, tag);
132 int i;
133
134 io->private_data = s;
135 calculate_stripe_array(conf, iod, s);
136
137 ublk_queue_alloc_sqes(q, sqe, s->nr);
138 for (i = 0; i < s->nr; i++) {
139 struct stripe *t = &s->s[i];
140
141 io_uring_prep_rw(op, sqe[i],
142 t->seq + 1,
143 (void *)t->vec,
144 t->nr_vec,
145 t->start << 9);
146 io_uring_sqe_set_flags(sqe[i], IOSQE_FIXED_FILE);
147 /* bit63 marks us as tgt io */
148 sqe[i]->user_data = build_user_data(tag, ublksrv_get_op(iod), i, 1);
149 }
150 return s->nr;
151 }
152
handle_flush(struct ublk_queue * q,const struct ublksrv_io_desc * iod,int tag)153 static int handle_flush(struct ublk_queue *q, const struct ublksrv_io_desc *iod, int tag)
154 {
155 const struct stripe_conf *conf = get_chunk_shift(q);
156 struct io_uring_sqe *sqe[NR_STRIPE];
157 int i;
158
159 ublk_queue_alloc_sqes(q, sqe, conf->nr_files);
160 for (i = 0; i < conf->nr_files; i++) {
161 io_uring_prep_fsync(sqe[i], i + 1, IORING_FSYNC_DATASYNC);
162 io_uring_sqe_set_flags(sqe[i], IOSQE_FIXED_FILE);
163 sqe[i]->user_data = build_user_data(tag, UBLK_IO_OP_FLUSH, 0, 1);
164 }
165 return conf->nr_files;
166 }
167
stripe_queue_tgt_io(struct ublk_queue * q,int tag)168 static int stripe_queue_tgt_io(struct ublk_queue *q, int tag)
169 {
170 const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
171 unsigned ublk_op = ublksrv_get_op(iod);
172 int ret = 0;
173
174 switch (ublk_op) {
175 case UBLK_IO_OP_FLUSH:
176 ret = handle_flush(q, iod, tag);
177 break;
178 case UBLK_IO_OP_WRITE_ZEROES:
179 case UBLK_IO_OP_DISCARD:
180 ret = -ENOTSUP;
181 break;
182 case UBLK_IO_OP_READ:
183 case UBLK_IO_OP_WRITE:
184 ret = stripe_queue_tgt_rw_io(q, iod, tag);
185 break;
186 default:
187 ret = -EINVAL;
188 break;
189 }
190 ublk_dbg(UBLK_DBG_IO, "%s: tag %d ublk io %x %llx %u ret %d\n", __func__, tag,
191 iod->op_flags, iod->start_sector, iod->nr_sectors << 9, ret);
192 return ret;
193 }
194
ublk_stripe_queue_io(struct ublk_queue * q,int tag)195 static int ublk_stripe_queue_io(struct ublk_queue *q, int tag)
196 {
197 int queued = stripe_queue_tgt_io(q, tag);
198
199 ublk_queued_tgt_io(q, tag, queued);
200 return 0;
201 }
202
ublk_stripe_io_done(struct ublk_queue * q,int tag,const struct io_uring_cqe * cqe)203 static void ublk_stripe_io_done(struct ublk_queue *q, int tag,
204 const struct io_uring_cqe *cqe)
205 {
206 const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
207 unsigned op = user_data_to_op(cqe->user_data);
208 struct ublk_io *io = ublk_get_io(q, tag);
209 int res = cqe->res;
210
211 if (res < 0) {
212 if (!io->result)
213 io->result = res;
214 ublk_err("%s: io failure %d tag %u\n", __func__, res, tag);
215 }
216
217 /* fail short READ/WRITE simply */
218 if (op == UBLK_IO_OP_READ || op == UBLK_IO_OP_WRITE) {
219 unsigned seq = user_data_to_tgt_data(cqe->user_data);
220 struct stripe_array *s = io->private_data;
221
222 if (res < s->s[seq].vec->iov_len)
223 io->result = -EIO;
224 }
225
226 if (ublk_completed_tgt_io(q, tag)) {
227 int res = io->result;
228
229 if (!res)
230 res = iod->nr_sectors << 9;
231
232 ublk_complete_io(q, tag, res);
233
234 free_stripe_array(io->private_data);
235 io->private_data = NULL;
236 }
237 }
238
ublk_stripe_tgt_init(const struct dev_ctx * ctx,struct ublk_dev * dev)239 static int ublk_stripe_tgt_init(const struct dev_ctx *ctx, struct ublk_dev *dev)
240 {
241 struct ublk_params p = {
242 .types = UBLK_PARAM_TYPE_BASIC,
243 .basic = {
244 .attrs = UBLK_ATTR_VOLATILE_CACHE,
245 .logical_bs_shift = 9,
246 .physical_bs_shift = 12,
247 .io_opt_shift = 12,
248 .io_min_shift = 9,
249 .max_sectors = dev->dev_info.max_io_buf_bytes >> 9,
250 },
251 };
252 unsigned chunk_size = ctx->chunk_size;
253 struct stripe_conf *conf;
254 unsigned chunk_shift;
255 loff_t bytes = 0;
256 int ret, i;
257
258 if ((chunk_size & (chunk_size - 1)) || !chunk_size) {
259 ublk_err("invalid chunk size %u\n", chunk_size);
260 return -EINVAL;
261 }
262
263 if (chunk_size < 4096 || chunk_size > 512 * 1024) {
264 ublk_err("invalid chunk size %u\n", chunk_size);
265 return -EINVAL;
266 }
267
268 chunk_shift = ilog2(chunk_size);
269
270 ret = backing_file_tgt_init(dev);
271 if (ret)
272 return ret;
273
274 if (!dev->tgt.nr_backing_files || dev->tgt.nr_backing_files > NR_STRIPE)
275 return -EINVAL;
276
277 assert(dev->nr_fds == dev->tgt.nr_backing_files + 1);
278
279 for (i = 0; i < dev->tgt.nr_backing_files; i++)
280 dev->tgt.backing_file_size[i] &= ~((1 << chunk_shift) - 1);
281
282 for (i = 0; i < dev->tgt.nr_backing_files; i++) {
283 unsigned long size = dev->tgt.backing_file_size[i];
284
285 if (size != dev->tgt.backing_file_size[0])
286 return -EINVAL;
287 bytes += size;
288 }
289
290 conf = malloc(sizeof(*conf));
291 conf->shift = chunk_shift;
292 conf->nr_files = dev->tgt.nr_backing_files;
293
294 dev->private_data = conf;
295 dev->tgt.dev_size = bytes;
296 p.basic.dev_sectors = bytes >> 9;
297 dev->tgt.params = p;
298 dev->tgt.sq_depth = dev->dev_info.queue_depth * conf->nr_files;
299 dev->tgt.cq_depth = dev->dev_info.queue_depth * conf->nr_files;
300
301 printf("%s: shift %u files %u\n", __func__, conf->shift, conf->nr_files);
302
303 return 0;
304 }
305
ublk_stripe_tgt_deinit(struct ublk_dev * dev)306 static void ublk_stripe_tgt_deinit(struct ublk_dev *dev)
307 {
308 free(dev->private_data);
309 backing_file_tgt_deinit(dev);
310 }
311
312 const struct ublk_tgt_ops stripe_tgt_ops = {
313 .name = "stripe",
314 .init_tgt = ublk_stripe_tgt_init,
315 .deinit_tgt = ublk_stripe_tgt_deinit,
316 .queue_io = ublk_stripe_queue_io,
317 .tgt_io_done = ublk_stripe_io_done,
318 };
319