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,void * base)72 static void calculate_stripe_array(const struct stripe_conf *conf,
73 const struct ublksrv_io_desc *iod, struct stripe_array *s, void *base)
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 *)(base + 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,int zc)114 static inline enum io_uring_op stripe_to_uring_op(
115 const struct ublksrv_io_desc *iod, int zc)
116 {
117 unsigned ublk_op = ublksrv_get_op(iod);
118
119 if (ublk_op == UBLK_IO_OP_READ)
120 return zc ? IORING_OP_READV_FIXED : IORING_OP_READV;
121 else if (ublk_op == UBLK_IO_OP_WRITE)
122 return zc ? IORING_OP_WRITEV_FIXED : IORING_OP_WRITEV;
123 assert(0);
124 }
125
stripe_queue_tgt_rw_io(struct ublk_queue * q,const struct ublksrv_io_desc * iod,int tag)126 static int stripe_queue_tgt_rw_io(struct ublk_queue *q, const struct ublksrv_io_desc *iod, int tag)
127 {
128 const struct stripe_conf *conf = get_chunk_shift(q);
129 unsigned auto_zc = (ublk_queue_use_auto_zc(q) != 0);
130 unsigned zc = (ublk_queue_use_zc(q) != 0);
131 enum io_uring_op op = stripe_to_uring_op(iod, zc | auto_zc);
132 struct io_uring_sqe *sqe[NR_STRIPE];
133 struct stripe_array *s = alloc_stripe_array(conf, iod);
134 struct ublk_io *io = ublk_get_io(q, tag);
135 int i, extra = zc ? 2 : 0;
136 void *base = (zc | auto_zc) ? NULL : (void *)iod->addr;
137
138 io->private_data = s;
139 calculate_stripe_array(conf, iod, s, base);
140
141 ublk_io_alloc_sqes(ublk_get_io(q, tag), sqe, s->nr + extra);
142
143 if (zc) {
144 io_uring_prep_buf_register(sqe[0], 0, tag, q->q_id, io->buf_index);
145 sqe[0]->flags |= IOSQE_CQE_SKIP_SUCCESS | IOSQE_IO_HARDLINK;
146 sqe[0]->user_data = build_user_data(tag,
147 ublk_cmd_op_nr(sqe[0]->cmd_op), 0, q->q_id, 1);
148 }
149
150 for (i = zc; i < s->nr + extra - zc; i++) {
151 struct stripe *t = &s->s[i - zc];
152
153 io_uring_prep_rw(op, sqe[i],
154 t->seq + 1,
155 (void *)t->vec,
156 t->nr_vec,
157 t->start << 9);
158 io_uring_sqe_set_flags(sqe[i], IOSQE_FIXED_FILE);
159 if (auto_zc || zc) {
160 sqe[i]->buf_index = tag;
161 if (zc)
162 sqe[i]->flags |= IOSQE_IO_HARDLINK;
163 }
164 /* bit63 marks us as tgt io */
165 sqe[i]->user_data = build_user_data(tag, ublksrv_get_op(iod), i - zc, q->q_id, 1);
166 }
167 if (zc) {
168 struct io_uring_sqe *unreg = sqe[s->nr + 1];
169
170 io_uring_prep_buf_unregister(unreg, 0, tag, q->q_id, io->buf_index);
171 unreg->user_data = build_user_data(
172 tag, ublk_cmd_op_nr(unreg->cmd_op), 0, q->q_id, 1);
173 }
174
175 /* register buffer is skip_success */
176 return s->nr + zc;
177 }
178
handle_flush(struct ublk_queue * q,const struct ublksrv_io_desc * iod,int tag)179 static int handle_flush(struct ublk_queue *q, const struct ublksrv_io_desc *iod, int tag)
180 {
181 const struct stripe_conf *conf = get_chunk_shift(q);
182 struct io_uring_sqe *sqe[NR_STRIPE];
183 int i;
184
185 ublk_io_alloc_sqes(ublk_get_io(q, tag), sqe, conf->nr_files);
186 for (i = 0; i < conf->nr_files; i++) {
187 io_uring_prep_fsync(sqe[i], i + 1, IORING_FSYNC_DATASYNC);
188 io_uring_sqe_set_flags(sqe[i], IOSQE_FIXED_FILE);
189 sqe[i]->user_data = build_user_data(tag, UBLK_IO_OP_FLUSH, 0, q->q_id, 1);
190 }
191 return conf->nr_files;
192 }
193
stripe_queue_tgt_io(struct ublk_queue * q,int tag)194 static int stripe_queue_tgt_io(struct ublk_queue *q, int tag)
195 {
196 const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
197 unsigned ublk_op = ublksrv_get_op(iod);
198 int ret = 0;
199
200 switch (ublk_op) {
201 case UBLK_IO_OP_FLUSH:
202 ret = handle_flush(q, iod, tag);
203 break;
204 case UBLK_IO_OP_WRITE_ZEROES:
205 case UBLK_IO_OP_DISCARD:
206 ret = -ENOTSUP;
207 break;
208 case UBLK_IO_OP_READ:
209 case UBLK_IO_OP_WRITE:
210 ret = stripe_queue_tgt_rw_io(q, iod, tag);
211 break;
212 default:
213 ret = -EINVAL;
214 break;
215 }
216 ublk_dbg(UBLK_DBG_IO, "%s: tag %d ublk io %x %llx %u ret %d\n", __func__, tag,
217 iod->op_flags, iod->start_sector, iod->nr_sectors << 9, ret);
218 return ret;
219 }
220
ublk_stripe_queue_io(struct ublk_queue * q,int tag)221 static int ublk_stripe_queue_io(struct ublk_queue *q, int tag)
222 {
223 int queued = stripe_queue_tgt_io(q, tag);
224
225 ublk_queued_tgt_io(q, tag, queued);
226 return 0;
227 }
228
ublk_stripe_io_done(struct ublk_queue * q,int tag,const struct io_uring_cqe * cqe)229 static void ublk_stripe_io_done(struct ublk_queue *q, int tag,
230 const struct io_uring_cqe *cqe)
231 {
232 const struct ublksrv_io_desc *iod = ublk_get_iod(q, tag);
233 unsigned op = user_data_to_op(cqe->user_data);
234 struct ublk_io *io = ublk_get_io(q, tag);
235 int res = cqe->res;
236
237 if (res < 0 || op != ublk_cmd_op_nr(UBLK_U_IO_UNREGISTER_IO_BUF)) {
238 if (!io->result)
239 io->result = res;
240 if (res < 0)
241 ublk_err("%s: io failure %d tag %u\n", __func__, res, tag);
242 }
243
244 /* buffer register op is IOSQE_CQE_SKIP_SUCCESS */
245 if (op == ublk_cmd_op_nr(UBLK_U_IO_REGISTER_IO_BUF))
246 io->tgt_ios += 1;
247
248 /* fail short READ/WRITE simply */
249 if (op == UBLK_IO_OP_READ || op == UBLK_IO_OP_WRITE) {
250 unsigned seq = user_data_to_tgt_data(cqe->user_data);
251 struct stripe_array *s = io->private_data;
252
253 if (res < s->s[seq].nr_sects << 9) {
254 io->result = -EIO;
255 ublk_err("%s: short rw op %u res %d exp %u tag %u\n",
256 __func__, op, res, s->s[seq].vec->iov_len, tag);
257 }
258 }
259
260 if (ublk_completed_tgt_io(q, tag)) {
261 int res = io->result;
262
263 if (!res)
264 res = iod->nr_sectors << 9;
265
266 ublk_complete_io(q, tag, res);
267
268 free_stripe_array(io->private_data);
269 io->private_data = NULL;
270 }
271 }
272
ublk_stripe_tgt_init(const struct dev_ctx * ctx,struct ublk_dev * dev)273 static int ublk_stripe_tgt_init(const struct dev_ctx *ctx, struct ublk_dev *dev)
274 {
275 struct ublk_params p = {
276 .types = UBLK_PARAM_TYPE_BASIC,
277 .basic = {
278 .attrs = UBLK_ATTR_VOLATILE_CACHE,
279 .logical_bs_shift = 9,
280 .physical_bs_shift = 12,
281 .io_opt_shift = 12,
282 .io_min_shift = 9,
283 .max_sectors = dev->dev_info.max_io_buf_bytes >> 9,
284 },
285 };
286 unsigned chunk_size = ctx->stripe.chunk_size;
287 struct stripe_conf *conf;
288 unsigned chunk_shift;
289 loff_t bytes = 0;
290 int ret, i, mul = 1;
291
292 if (ctx->auto_zc_fallback) {
293 ublk_err("%s: not support auto_zc_fallback\n", __func__);
294 return -EINVAL;
295 }
296
297 if ((chunk_size & (chunk_size - 1)) || !chunk_size) {
298 ublk_err("invalid chunk size %u\n", chunk_size);
299 return -EINVAL;
300 }
301
302 if (chunk_size < 4096 || chunk_size > 512 * 1024) {
303 ublk_err("invalid chunk size %u\n", chunk_size);
304 return -EINVAL;
305 }
306
307 chunk_shift = ilog2(chunk_size);
308
309 ret = backing_file_tgt_init(dev);
310 if (ret)
311 return ret;
312
313 if (!dev->tgt.nr_backing_files || dev->tgt.nr_backing_files > NR_STRIPE)
314 return -EINVAL;
315
316 assert(dev->nr_fds == dev->tgt.nr_backing_files + 1);
317
318 for (i = 0; i < dev->tgt.nr_backing_files; i++)
319 dev->tgt.backing_file_size[i] &= ~((1 << chunk_shift) - 1);
320
321 for (i = 0; i < dev->tgt.nr_backing_files; i++) {
322 unsigned long size = dev->tgt.backing_file_size[i];
323
324 if (size != dev->tgt.backing_file_size[0])
325 return -EINVAL;
326 bytes += size;
327 }
328
329 conf = malloc(sizeof(*conf));
330 conf->shift = chunk_shift;
331 conf->nr_files = dev->tgt.nr_backing_files;
332
333 dev->private_data = conf;
334 dev->tgt.dev_size = bytes;
335 p.basic.dev_sectors = bytes >> 9;
336 dev->tgt.params = p;
337
338 if (dev->dev_info.flags & UBLK_F_SUPPORT_ZERO_COPY)
339 mul = 2;
340 dev->tgt.sq_depth = mul * dev->dev_info.queue_depth * conf->nr_files;
341 dev->tgt.cq_depth = mul * dev->dev_info.queue_depth * conf->nr_files;
342
343 printf("%s: shift %u files %u\n", __func__, conf->shift, conf->nr_files);
344
345 return 0;
346 }
347
ublk_stripe_tgt_deinit(struct ublk_dev * dev)348 static void ublk_stripe_tgt_deinit(struct ublk_dev *dev)
349 {
350 free(dev->private_data);
351 backing_file_tgt_deinit(dev);
352 }
353
ublk_stripe_cmd_line(struct dev_ctx * ctx,int argc,char * argv[])354 static void ublk_stripe_cmd_line(struct dev_ctx *ctx, int argc, char *argv[])
355 {
356 static const struct option longopts[] = {
357 { "chunk_size", 1, NULL, 0 },
358 { 0, 0, 0, 0 }
359 };
360 int option_idx, opt;
361
362 ctx->stripe.chunk_size = 65536;
363 while ((opt = getopt_long(argc, argv, "",
364 longopts, &option_idx)) != -1) {
365 switch (opt) {
366 case 0:
367 if (!strcmp(longopts[option_idx].name, "chunk_size"))
368 ctx->stripe.chunk_size = strtol(optarg, NULL, 10);
369 }
370 }
371 }
372
ublk_stripe_usage(const struct ublk_tgt_ops * ops)373 static void ublk_stripe_usage(const struct ublk_tgt_ops *ops)
374 {
375 printf("\tstripe: [--chunk_size chunk_size (default 65536)]\n");
376 }
377
378 const struct ublk_tgt_ops stripe_tgt_ops = {
379 .name = "stripe",
380 .init_tgt = ublk_stripe_tgt_init,
381 .deinit_tgt = ublk_stripe_tgt_deinit,
382 .queue_io = ublk_stripe_queue_io,
383 .tgt_io_done = ublk_stripe_io_done,
384 .parse_cmd_line = ublk_stripe_cmd_line,
385 .usage = ublk_stripe_usage,
386 };
387