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3b77495a JA |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/kernel.h> | |
3 | #include <linux/errno.h> | |
4 | #include <linux/fs.h> | |
5 | #include <linux/file.h> | |
6 | #include <linux/mm.h> | |
7 | #include <linux/slab.h> | |
8 | #include <linux/namei.h> | |
9 | #include <linux/poll.h> | |
10 | #include <linux/io_uring.h> | |
11 | ||
12 | #include <uapi/linux/io_uring.h> | |
13 | ||
3b77495a JA |
14 | #include "io_uring.h" |
15 | #include "opdef.h" | |
16 | #include "kbuf.h" | |
17 | ||
18 | #define IO_BUFFER_LIST_BUF_PER_PAGE (PAGE_SIZE / sizeof(struct io_uring_buf)) | |
19 | ||
20 | #define BGID_ARRAY 64 | |
21 | ||
22 | struct io_provide_buf { | |
23 | struct file *file; | |
24 | __u64 addr; | |
25 | __u32 len; | |
26 | __u32 bgid; | |
27 | __u16 nbufs; | |
28 | __u16 bid; | |
29 | }; | |
30 | ||
31 | static inline struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx, | |
32 | unsigned int bgid) | |
33 | { | |
34 | if (ctx->io_bl && bgid < BGID_ARRAY) | |
35 | return &ctx->io_bl[bgid]; | |
36 | ||
37 | return xa_load(&ctx->io_bl_xa, bgid); | |
38 | } | |
39 | ||
024b8fde HX |
40 | static int io_buffer_add_list(struct io_ring_ctx *ctx, |
41 | struct io_buffer_list *bl, unsigned int bgid) | |
42 | { | |
43 | bl->bgid = bgid; | |
44 | if (bgid < BGID_ARRAY) | |
45 | return 0; | |
46 | ||
47 | return xa_err(xa_store(&ctx->io_bl_xa, bgid, bl, GFP_KERNEL)); | |
48 | } | |
49 | ||
50 | void io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags) | |
3b77495a JA |
51 | { |
52 | struct io_ring_ctx *ctx = req->ctx; | |
53 | struct io_buffer_list *bl; | |
54 | struct io_buffer *buf; | |
55 | ||
56 | /* | |
024b8fde HX |
57 | * For legacy provided buffer mode, don't recycle if we already did |
58 | * IO to this buffer. For ring-mapped provided buffer mode, we should | |
59 | * increment ring->head to explicitly monopolize the buffer to avoid | |
60 | * multiple use. | |
3b77495a | 61 | */ |
024b8fde | 62 | if (req->flags & REQ_F_PARTIAL_IO) |
3b77495a | 63 | return; |
3b77495a JA |
64 | |
65 | io_ring_submit_lock(ctx, issue_flags); | |
66 | ||
67 | buf = req->kbuf; | |
68 | bl = io_buffer_get_list(ctx, buf->bgid); | |
69 | list_add(&buf->list, &bl->buf_list); | |
70 | req->flags &= ~REQ_F_BUFFER_SELECTED; | |
71 | req->buf_index = buf->bgid; | |
72 | ||
73 | io_ring_submit_unlock(ctx, issue_flags); | |
024b8fde | 74 | return; |
3b77495a JA |
75 | } |
76 | ||
53ccf69b PB |
77 | unsigned int __io_put_kbuf(struct io_kiocb *req, unsigned issue_flags) |
78 | { | |
79 | unsigned int cflags; | |
80 | ||
81 | /* | |
82 | * We can add this buffer back to two lists: | |
83 | * | |
84 | * 1) The io_buffers_cache list. This one is protected by the | |
85 | * ctx->uring_lock. If we already hold this lock, add back to this | |
86 | * list as we can grab it from issue as well. | |
87 | * 2) The io_buffers_comp list. This one is protected by the | |
88 | * ctx->completion_lock. | |
89 | * | |
90 | * We migrate buffers from the comp_list to the issue cache list | |
91 | * when we need one. | |
92 | */ | |
93 | if (req->flags & REQ_F_BUFFER_RING) { | |
94 | /* no buffers to recycle for this case */ | |
95 | cflags = __io_put_kbuf_list(req, NULL); | |
96 | } else if (issue_flags & IO_URING_F_UNLOCKED) { | |
97 | struct io_ring_ctx *ctx = req->ctx; | |
98 | ||
99 | spin_lock(&ctx->completion_lock); | |
100 | cflags = __io_put_kbuf_list(req, &ctx->io_buffers_comp); | |
101 | spin_unlock(&ctx->completion_lock); | |
102 | } else { | |
103 | lockdep_assert_held(&req->ctx->uring_lock); | |
104 | ||
105 | cflags = __io_put_kbuf_list(req, &req->ctx->io_buffers_cache); | |
106 | } | |
107 | return cflags; | |
108 | } | |
109 | ||
3b77495a JA |
110 | static void __user *io_provided_buffer_select(struct io_kiocb *req, size_t *len, |
111 | struct io_buffer_list *bl) | |
112 | { | |
113 | if (!list_empty(&bl->buf_list)) { | |
114 | struct io_buffer *kbuf; | |
115 | ||
116 | kbuf = list_first_entry(&bl->buf_list, struct io_buffer, list); | |
117 | list_del(&kbuf->list); | |
b8c01559 | 118 | if (*len == 0 || *len > kbuf->len) |
3b77495a JA |
119 | *len = kbuf->len; |
120 | req->flags |= REQ_F_BUFFER_SELECTED; | |
121 | req->kbuf = kbuf; | |
122 | req->buf_index = kbuf->bid; | |
123 | return u64_to_user_ptr(kbuf->addr); | |
124 | } | |
125 | return NULL; | |
126 | } | |
127 | ||
128 | static void __user *io_ring_buffer_select(struct io_kiocb *req, size_t *len, | |
129 | struct io_buffer_list *bl, | |
130 | unsigned int issue_flags) | |
131 | { | |
132 | struct io_uring_buf_ring *br = bl->buf_ring; | |
133 | struct io_uring_buf *buf; | |
134 | __u16 head = bl->head; | |
135 | ||
136 | if (unlikely(smp_load_acquire(&br->tail) == head)) | |
137 | return NULL; | |
138 | ||
139 | head &= bl->mask; | |
c56e022c JA |
140 | /* mmaped buffers are always contig */ |
141 | if (bl->is_mmap || head < IO_BUFFER_LIST_BUF_PER_PAGE) { | |
3b77495a JA |
142 | buf = &br->bufs[head]; |
143 | } else { | |
144 | int off = head & (IO_BUFFER_LIST_BUF_PER_PAGE - 1); | |
145 | int index = head / IO_BUFFER_LIST_BUF_PER_PAGE; | |
146 | buf = page_address(bl->buf_pages[index]); | |
147 | buf += off; | |
148 | } | |
b8c01559 | 149 | if (*len == 0 || *len > buf->len) |
3b77495a JA |
150 | *len = buf->len; |
151 | req->flags |= REQ_F_BUFFER_RING; | |
152 | req->buf_list = bl; | |
153 | req->buf_index = buf->bid; | |
154 | ||
155 | if (issue_flags & IO_URING_F_UNLOCKED || !file_can_poll(req->file)) { | |
156 | /* | |
157 | * If we came in unlocked, we have no choice but to consume the | |
f09c8643 HX |
158 | * buffer here, otherwise nothing ensures that the buffer won't |
159 | * get used by others. This does mean it'll be pinned until the | |
160 | * IO completes, coming in unlocked means we're being called from | |
161 | * io-wq context and there may be further retries in async hybrid | |
162 | * mode. For the locked case, the caller must call commit when | |
163 | * the transfer completes (or if we get -EAGAIN and must poll of | |
164 | * retry). | |
3b77495a JA |
165 | */ |
166 | req->buf_list = NULL; | |
167 | bl->head++; | |
168 | } | |
169 | return u64_to_user_ptr(buf->addr); | |
170 | } | |
171 | ||
172 | void __user *io_buffer_select(struct io_kiocb *req, size_t *len, | |
173 | unsigned int issue_flags) | |
174 | { | |
175 | struct io_ring_ctx *ctx = req->ctx; | |
176 | struct io_buffer_list *bl; | |
177 | void __user *ret = NULL; | |
178 | ||
179 | io_ring_submit_lock(req->ctx, issue_flags); | |
180 | ||
181 | bl = io_buffer_get_list(ctx, req->buf_index); | |
182 | if (likely(bl)) { | |
25a2c188 | 183 | if (bl->is_mapped) |
3b77495a JA |
184 | ret = io_ring_buffer_select(req, len, bl, issue_flags); |
185 | else | |
186 | ret = io_provided_buffer_select(req, len, bl); | |
187 | } | |
188 | io_ring_submit_unlock(req->ctx, issue_flags); | |
189 | return ret; | |
190 | } | |
191 | ||
192 | static __cold int io_init_bl_list(struct io_ring_ctx *ctx) | |
193 | { | |
194 | int i; | |
195 | ||
196 | ctx->io_bl = kcalloc(BGID_ARRAY, sizeof(struct io_buffer_list), | |
197 | GFP_KERNEL); | |
198 | if (!ctx->io_bl) | |
199 | return -ENOMEM; | |
200 | ||
201 | for (i = 0; i < BGID_ARRAY; i++) { | |
202 | INIT_LIST_HEAD(&ctx->io_bl[i].buf_list); | |
203 | ctx->io_bl[i].bgid = i; | |
204 | } | |
205 | ||
206 | return 0; | |
207 | } | |
208 | ||
209 | static int __io_remove_buffers(struct io_ring_ctx *ctx, | |
210 | struct io_buffer_list *bl, unsigned nbufs) | |
211 | { | |
212 | unsigned i = 0; | |
213 | ||
214 | /* shouldn't happen */ | |
215 | if (!nbufs) | |
216 | return 0; | |
217 | ||
c56e022c | 218 | if (bl->is_mapped) { |
3b77495a | 219 | i = bl->buf_ring->tail - bl->head; |
c56e022c | 220 | if (bl->is_mmap) { |
99a9e0b8 | 221 | folio_put(virt_to_folio(bl->buf_ring)); |
ceac766a | 222 | bl->buf_ring = NULL; |
c56e022c JA |
223 | bl->is_mmap = 0; |
224 | } else if (bl->buf_nr_pages) { | |
225 | int j; | |
226 | ||
227 | for (j = 0; j < bl->buf_nr_pages; j++) | |
228 | unpin_user_page(bl->buf_pages[j]); | |
229 | kvfree(bl->buf_pages); | |
230 | bl->buf_pages = NULL; | |
231 | bl->buf_nr_pages = 0; | |
232 | } | |
3b77495a JA |
233 | /* make sure it's seen as empty */ |
234 | INIT_LIST_HEAD(&bl->buf_list); | |
25a2c188 | 235 | bl->is_mapped = 0; |
3b77495a JA |
236 | return i; |
237 | } | |
238 | ||
b4a72c05 WL |
239 | /* protects io_buffers_cache */ |
240 | lockdep_assert_held(&ctx->uring_lock); | |
241 | ||
3b77495a JA |
242 | while (!list_empty(&bl->buf_list)) { |
243 | struct io_buffer *nxt; | |
244 | ||
245 | nxt = list_first_entry(&bl->buf_list, struct io_buffer, list); | |
b4a72c05 | 246 | list_move(&nxt->list, &ctx->io_buffers_cache); |
3b77495a JA |
247 | if (++i == nbufs) |
248 | return i; | |
249 | cond_resched(); | |
250 | } | |
3b77495a JA |
251 | |
252 | return i; | |
253 | } | |
254 | ||
255 | void io_destroy_buffers(struct io_ring_ctx *ctx) | |
256 | { | |
257 | struct io_buffer_list *bl; | |
258 | unsigned long index; | |
259 | int i; | |
260 | ||
261 | for (i = 0; i < BGID_ARRAY; i++) { | |
262 | if (!ctx->io_bl) | |
263 | break; | |
264 | __io_remove_buffers(ctx, &ctx->io_bl[i], -1U); | |
265 | } | |
266 | ||
267 | xa_for_each(&ctx->io_bl_xa, index, bl) { | |
268 | xa_erase(&ctx->io_bl_xa, bl->bgid); | |
269 | __io_remove_buffers(ctx, bl, -1U); | |
270 | kfree(bl); | |
271 | } | |
272 | ||
273 | while (!list_empty(&ctx->io_buffers_pages)) { | |
274 | struct page *page; | |
275 | ||
276 | page = list_first_entry(&ctx->io_buffers_pages, struct page, lru); | |
277 | list_del_init(&page->lru); | |
278 | __free_page(page); | |
279 | } | |
280 | } | |
281 | ||
282 | int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) | |
283 | { | |
f2ccb5ae | 284 | struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); |
3b77495a JA |
285 | u64 tmp; |
286 | ||
287 | if (sqe->rw_flags || sqe->addr || sqe->len || sqe->off || | |
288 | sqe->splice_fd_in) | |
289 | return -EINVAL; | |
290 | ||
291 | tmp = READ_ONCE(sqe->fd); | |
292 | if (!tmp || tmp > USHRT_MAX) | |
293 | return -EINVAL; | |
294 | ||
295 | memset(p, 0, sizeof(*p)); | |
296 | p->nbufs = tmp; | |
297 | p->bgid = READ_ONCE(sqe->buf_group); | |
298 | return 0; | |
299 | } | |
300 | ||
301 | int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags) | |
302 | { | |
f2ccb5ae | 303 | struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); |
3b77495a JA |
304 | struct io_ring_ctx *ctx = req->ctx; |
305 | struct io_buffer_list *bl; | |
306 | int ret = 0; | |
307 | ||
308 | io_ring_submit_lock(ctx, issue_flags); | |
309 | ||
310 | ret = -ENOENT; | |
311 | bl = io_buffer_get_list(ctx, p->bgid); | |
312 | if (bl) { | |
313 | ret = -EINVAL; | |
314 | /* can't use provide/remove buffers command on mapped buffers */ | |
25a2c188 | 315 | if (!bl->is_mapped) |
3b77495a JA |
316 | ret = __io_remove_buffers(ctx, bl, p->nbufs); |
317 | } | |
c3b49093 | 318 | io_ring_submit_unlock(ctx, issue_flags); |
3b77495a JA |
319 | if (ret < 0) |
320 | req_set_fail(req); | |
3b77495a | 321 | io_req_set_res(req, ret, 0); |
c3b49093 | 322 | return IOU_OK; |
3b77495a JA |
323 | } |
324 | ||
325 | int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) | |
326 | { | |
327 | unsigned long size, tmp_check; | |
f2ccb5ae | 328 | struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); |
3b77495a JA |
329 | u64 tmp; |
330 | ||
331 | if (sqe->rw_flags || sqe->splice_fd_in) | |
332 | return -EINVAL; | |
333 | ||
334 | tmp = READ_ONCE(sqe->fd); | |
335 | if (!tmp || tmp > USHRT_MAX) | |
336 | return -E2BIG; | |
337 | p->nbufs = tmp; | |
338 | p->addr = READ_ONCE(sqe->addr); | |
339 | p->len = READ_ONCE(sqe->len); | |
340 | ||
341 | if (check_mul_overflow((unsigned long)p->len, (unsigned long)p->nbufs, | |
342 | &size)) | |
343 | return -EOVERFLOW; | |
344 | if (check_add_overflow((unsigned long)p->addr, size, &tmp_check)) | |
345 | return -EOVERFLOW; | |
346 | ||
347 | size = (unsigned long)p->len * p->nbufs; | |
348 | if (!access_ok(u64_to_user_ptr(p->addr), size)) | |
349 | return -EFAULT; | |
350 | ||
351 | p->bgid = READ_ONCE(sqe->buf_group); | |
352 | tmp = READ_ONCE(sqe->off); | |
353 | if (tmp > USHRT_MAX) | |
354 | return -E2BIG; | |
3851d25c JA |
355 | if (tmp + p->nbufs >= USHRT_MAX) |
356 | return -EINVAL; | |
3b77495a JA |
357 | p->bid = tmp; |
358 | return 0; | |
359 | } | |
360 | ||
361 | static int io_refill_buffer_cache(struct io_ring_ctx *ctx) | |
362 | { | |
363 | struct io_buffer *buf; | |
364 | struct page *page; | |
365 | int bufs_in_page; | |
366 | ||
367 | /* | |
368 | * Completions that don't happen inline (eg not under uring_lock) will | |
369 | * add to ->io_buffers_comp. If we don't have any free buffers, check | |
370 | * the completion list and splice those entries first. | |
371 | */ | |
372 | if (!list_empty_careful(&ctx->io_buffers_comp)) { | |
373 | spin_lock(&ctx->completion_lock); | |
374 | if (!list_empty(&ctx->io_buffers_comp)) { | |
375 | list_splice_init(&ctx->io_buffers_comp, | |
376 | &ctx->io_buffers_cache); | |
377 | spin_unlock(&ctx->completion_lock); | |
378 | return 0; | |
379 | } | |
380 | spin_unlock(&ctx->completion_lock); | |
381 | } | |
382 | ||
383 | /* | |
384 | * No free buffers and no completion entries either. Allocate a new | |
385 | * page worth of buffer entries and add those to our freelist. | |
386 | */ | |
387 | page = alloc_page(GFP_KERNEL_ACCOUNT); | |
388 | if (!page) | |
389 | return -ENOMEM; | |
390 | ||
391 | list_add(&page->lru, &ctx->io_buffers_pages); | |
392 | ||
393 | buf = page_address(page); | |
394 | bufs_in_page = PAGE_SIZE / sizeof(*buf); | |
395 | while (bufs_in_page) { | |
396 | list_add_tail(&buf->list, &ctx->io_buffers_cache); | |
397 | buf++; | |
398 | bufs_in_page--; | |
399 | } | |
400 | ||
401 | return 0; | |
402 | } | |
403 | ||
404 | static int io_add_buffers(struct io_ring_ctx *ctx, struct io_provide_buf *pbuf, | |
405 | struct io_buffer_list *bl) | |
406 | { | |
407 | struct io_buffer *buf; | |
408 | u64 addr = pbuf->addr; | |
409 | int i, bid = pbuf->bid; | |
410 | ||
411 | for (i = 0; i < pbuf->nbufs; i++) { | |
412 | if (list_empty(&ctx->io_buffers_cache) && | |
413 | io_refill_buffer_cache(ctx)) | |
414 | break; | |
415 | buf = list_first_entry(&ctx->io_buffers_cache, struct io_buffer, | |
416 | list); | |
417 | list_move_tail(&buf->list, &bl->buf_list); | |
418 | buf->addr = addr; | |
419 | buf->len = min_t(__u32, pbuf->len, MAX_RW_COUNT); | |
420 | buf->bid = bid; | |
421 | buf->bgid = pbuf->bgid; | |
422 | addr += pbuf->len; | |
423 | bid++; | |
424 | cond_resched(); | |
425 | } | |
426 | ||
427 | return i ? 0 : -ENOMEM; | |
428 | } | |
429 | ||
430 | int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags) | |
431 | { | |
f2ccb5ae | 432 | struct io_provide_buf *p = io_kiocb_to_cmd(req, struct io_provide_buf); |
3b77495a JA |
433 | struct io_ring_ctx *ctx = req->ctx; |
434 | struct io_buffer_list *bl; | |
435 | int ret = 0; | |
436 | ||
437 | io_ring_submit_lock(ctx, issue_flags); | |
438 | ||
439 | if (unlikely(p->bgid < BGID_ARRAY && !ctx->io_bl)) { | |
440 | ret = io_init_bl_list(ctx); | |
441 | if (ret) | |
442 | goto err; | |
443 | } | |
444 | ||
445 | bl = io_buffer_get_list(ctx, p->bgid); | |
446 | if (unlikely(!bl)) { | |
cc18cc5e | 447 | bl = kzalloc(sizeof(*bl), GFP_KERNEL_ACCOUNT); |
3b77495a JA |
448 | if (!bl) { |
449 | ret = -ENOMEM; | |
450 | goto err; | |
451 | } | |
452 | INIT_LIST_HEAD(&bl->buf_list); | |
453 | ret = io_buffer_add_list(ctx, bl, p->bgid); | |
454 | if (ret) { | |
455 | kfree(bl); | |
456 | goto err; | |
457 | } | |
458 | } | |
459 | /* can't add buffers via this command for a mapped buffer ring */ | |
25a2c188 | 460 | if (bl->is_mapped) { |
3b77495a JA |
461 | ret = -EINVAL; |
462 | goto err; | |
463 | } | |
464 | ||
465 | ret = io_add_buffers(ctx, p, bl); | |
466 | err: | |
c3b49093 PB |
467 | io_ring_submit_unlock(ctx, issue_flags); |
468 | ||
3b77495a JA |
469 | if (ret < 0) |
470 | req_set_fail(req); | |
3b77495a | 471 | io_req_set_res(req, ret, 0); |
c3b49093 | 472 | return IOU_OK; |
3b77495a JA |
473 | } |
474 | ||
ba56b632 JA |
475 | static int io_pin_pbuf_ring(struct io_uring_buf_reg *reg, |
476 | struct io_buffer_list *bl) | |
3b77495a JA |
477 | { |
478 | struct io_uring_buf_ring *br; | |
3b77495a | 479 | struct page **pages; |
f8024f1f | 480 | int i, nr_pages; |
3b77495a | 481 | |
ba56b632 JA |
482 | pages = io_pin_pages(reg->ring_addr, |
483 | flex_array_size(br, bufs, reg->ring_entries), | |
484 | &nr_pages); | |
485 | if (IS_ERR(pages)) | |
486 | return PTR_ERR(pages); | |
487 | ||
f8024f1f JA |
488 | /* |
489 | * Apparently some 32-bit boxes (ARM) will return highmem pages, | |
490 | * which then need to be mapped. We could support that, but it'd | |
491 | * complicate the code and slowdown the common cases quite a bit. | |
492 | * So just error out, returning -EINVAL just like we did on kernels | |
493 | * that didn't support mapped buffer rings. | |
494 | */ | |
495 | for (i = 0; i < nr_pages; i++) | |
496 | if (PageHighMem(pages[i])) | |
497 | goto error_unpin; | |
498 | ||
ba56b632 | 499 | br = page_address(pages[0]); |
fcb46c0c JA |
500 | #ifdef SHM_COLOUR |
501 | /* | |
502 | * On platforms that have specific aliasing requirements, SHM_COLOUR | |
503 | * is set and we must guarantee that the kernel and user side align | |
504 | * nicely. We cannot do that if IOU_PBUF_RING_MMAP isn't set and | |
505 | * the application mmap's the provided ring buffer. Fail the request | |
506 | * if we, by chance, don't end up with aligned addresses. The app | |
507 | * should use IOU_PBUF_RING_MMAP instead, and liburing will handle | |
508 | * this transparently. | |
509 | */ | |
f8024f1f JA |
510 | if ((reg->ring_addr | (unsigned long) br) & (SHM_COLOUR - 1)) |
511 | goto error_unpin; | |
fcb46c0c | 512 | #endif |
ba56b632 JA |
513 | bl->buf_pages = pages; |
514 | bl->buf_nr_pages = nr_pages; | |
515 | bl->buf_ring = br; | |
25a2c188 | 516 | bl->is_mapped = 1; |
c56e022c JA |
517 | bl->is_mmap = 0; |
518 | return 0; | |
f8024f1f JA |
519 | error_unpin: |
520 | for (i = 0; i < nr_pages; i++) | |
521 | unpin_user_page(pages[i]); | |
522 | kvfree(pages); | |
523 | return -EINVAL; | |
c56e022c JA |
524 | } |
525 | ||
526 | static int io_alloc_pbuf_ring(struct io_uring_buf_reg *reg, | |
527 | struct io_buffer_list *bl) | |
528 | { | |
529 | gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP; | |
530 | size_t ring_size; | |
531 | void *ptr; | |
532 | ||
533 | ring_size = reg->ring_entries * sizeof(struct io_uring_buf_ring); | |
534 | ptr = (void *) __get_free_pages(gfp, get_order(ring_size)); | |
535 | if (!ptr) | |
536 | return -ENOMEM; | |
537 | ||
538 | bl->buf_ring = ptr; | |
539 | bl->is_mapped = 1; | |
540 | bl->is_mmap = 1; | |
ba56b632 JA |
541 | return 0; |
542 | } | |
543 | ||
544 | int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) | |
545 | { | |
546 | struct io_uring_buf_reg reg; | |
547 | struct io_buffer_list *bl, *free_bl = NULL; | |
548 | int ret; | |
549 | ||
3b77495a JA |
550 | if (copy_from_user(®, arg, sizeof(reg))) |
551 | return -EFAULT; | |
552 | ||
81cf17cd | 553 | if (reg.resv[0] || reg.resv[1] || reg.resv[2]) |
3b77495a | 554 | return -EINVAL; |
c56e022c | 555 | if (reg.flags & ~IOU_PBUF_RING_MMAP) |
3b77495a | 556 | return -EINVAL; |
c56e022c JA |
557 | if (!(reg.flags & IOU_PBUF_RING_MMAP)) { |
558 | if (!reg.ring_addr) | |
559 | return -EFAULT; | |
560 | if (reg.ring_addr & ~PAGE_MASK) | |
561 | return -EINVAL; | |
562 | } else { | |
563 | if (reg.ring_addr) | |
564 | return -EINVAL; | |
565 | } | |
566 | ||
3b77495a JA |
567 | if (!is_power_of_2(reg.ring_entries)) |
568 | return -EINVAL; | |
569 | ||
570 | /* cannot disambiguate full vs empty due to head/tail size */ | |
571 | if (reg.ring_entries >= 65536) | |
572 | return -EINVAL; | |
573 | ||
574 | if (unlikely(reg.bgid < BGID_ARRAY && !ctx->io_bl)) { | |
575 | int ret = io_init_bl_list(ctx); | |
576 | if (ret) | |
577 | return ret; | |
578 | } | |
579 | ||
580 | bl = io_buffer_get_list(ctx, reg.bgid); | |
581 | if (bl) { | |
582 | /* if mapped buffer ring OR classic exists, don't allow */ | |
25a2c188 | 583 | if (bl->is_mapped || !list_empty(&bl->buf_list)) |
3b77495a JA |
584 | return -EEXIST; |
585 | } else { | |
586 | free_bl = bl = kzalloc(sizeof(*bl), GFP_KERNEL); | |
587 | if (!bl) | |
588 | return -ENOMEM; | |
589 | } | |
590 | ||
c56e022c JA |
591 | if (!(reg.flags & IOU_PBUF_RING_MMAP)) |
592 | ret = io_pin_pbuf_ring(®, bl); | |
593 | else | |
594 | ret = io_alloc_pbuf_ring(®, bl); | |
3b77495a | 595 | |
c56e022c JA |
596 | if (!ret) { |
597 | bl->nr_entries = reg.ring_entries; | |
598 | bl->mask = reg.ring_entries - 1; | |
ba56b632 | 599 | |
c56e022c JA |
600 | io_buffer_add_list(ctx, bl, reg.bgid); |
601 | return 0; | |
3b77495a JA |
602 | } |
603 | ||
c56e022c JA |
604 | kfree(free_bl); |
605 | return ret; | |
3b77495a JA |
606 | } |
607 | ||
608 | int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg) | |
609 | { | |
610 | struct io_uring_buf_reg reg; | |
611 | struct io_buffer_list *bl; | |
612 | ||
613 | if (copy_from_user(®, arg, sizeof(reg))) | |
614 | return -EFAULT; | |
81cf17cd JA |
615 | if (reg.resv[0] || reg.resv[1] || reg.resv[2]) |
616 | return -EINVAL; | |
617 | if (reg.flags) | |
3b77495a JA |
618 | return -EINVAL; |
619 | ||
620 | bl = io_buffer_get_list(ctx, reg.bgid); | |
621 | if (!bl) | |
622 | return -ENOENT; | |
25a2c188 | 623 | if (!bl->is_mapped) |
3b77495a JA |
624 | return -EINVAL; |
625 | ||
626 | __io_remove_buffers(ctx, bl, -1U); | |
627 | if (bl->bgid >= BGID_ARRAY) { | |
628 | xa_erase(&ctx->io_bl_xa, bl->bgid); | |
629 | kfree(bl); | |
630 | } | |
631 | return 0; | |
632 | } | |
c56e022c JA |
633 | |
634 | void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid) | |
635 | { | |
636 | struct io_buffer_list *bl; | |
637 | ||
638 | bl = io_buffer_get_list(ctx, bgid); | |
639 | if (!bl || !bl->is_mmap) | |
640 | return NULL; | |
641 | ||
642 | return bl->buf_ring; | |
643 | } |