1 /*
2  * Copyright(c) 2015-2017 Intel Corporation.
3  *
4  * This file is provided under a dual BSD/GPLv2 license.  When using or
5  * redistributing this file, you may do so under either license.
6  *
7  * GPL LICENSE SUMMARY
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of version 2 of the GNU General Public License as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * BSD LICENSE
19  *
20  * Redistribution and use in source and binary forms, with or without
21  * modification, are permitted provided that the following conditions
22  * are met:
23  *
24  *  - Redistributions of source code must retain the above copyright
25  *    notice, this list of conditions and the following disclaimer.
26  *  - Redistributions in binary form must reproduce the above copyright
27  *    notice, this list of conditions and the following disclaimer in
28  *    the documentation and/or other materials provided with the
29  *    distribution.
30  *  - Neither the name of Intel Corporation nor the names of its
31  *    contributors may be used to endorse or promote products derived
32  *    from this software without specific prior written permission.
33  *
34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
35  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
36  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
37  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
38  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
41  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
42  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
43  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
45  *
46  */
47 #include <asm/page.h>
48 #include <linux/string.h>
49 
50 #include "mmu_rb.h"
51 #include "user_exp_rcv.h"
52 #include "trace.h"
53 
54 static void unlock_exp_tids(struct hfi1_ctxtdata *uctxt,
55 			    struct exp_tid_set *set,
56 			    struct hfi1_filedata *fd);
57 static u32 find_phys_blocks(struct tid_user_buf *tidbuf, unsigned int npages);
58 static int set_rcvarray_entry(struct hfi1_filedata *fd,
59 			      struct tid_user_buf *tbuf,
60 			      u32 rcventry, struct tid_group *grp,
61 			      u16 pageidx, unsigned int npages);
62 static int tid_rb_insert(void *arg, struct mmu_rb_node *node);
63 static void cacheless_tid_rb_remove(struct hfi1_filedata *fdata,
64 				    struct tid_rb_node *tnode);
65 static void tid_rb_remove(void *arg, struct mmu_rb_node *node);
66 static int tid_rb_invalidate(void *arg, struct mmu_rb_node *mnode);
67 static int program_rcvarray(struct hfi1_filedata *fd, struct tid_user_buf *,
68 			    struct tid_group *grp,
69 			    unsigned int start, u16 count,
70 			    u32 *tidlist, unsigned int *tididx,
71 			    unsigned int *pmapped);
72 static int unprogram_rcvarray(struct hfi1_filedata *fd, u32 tidinfo,
73 			      struct tid_group **grp);
74 static void clear_tid_node(struct hfi1_filedata *fd, struct tid_rb_node *node);
75 
76 static struct mmu_rb_ops tid_rb_ops = {
77 	.insert = tid_rb_insert,
78 	.remove = tid_rb_remove,
79 	.invalidate = tid_rb_invalidate
80 };
81 
82 /*
83  * Initialize context and file private data needed for Expected
84  * receive caching. This needs to be done after the context has
85  * been configured with the eager/expected RcvEntry counts.
86  */
87 int hfi1_user_exp_rcv_init(struct hfi1_filedata *fd,
88 			   struct hfi1_ctxtdata *uctxt)
89 {
90 	struct hfi1_devdata *dd = uctxt->dd;
91 	int ret = 0;
92 
93 	spin_lock_init(&fd->tid_lock);
94 	spin_lock_init(&fd->invalid_lock);
95 
96 	fd->entry_to_rb = kcalloc(uctxt->expected_count,
97 				  sizeof(struct rb_node *),
98 				  GFP_KERNEL);
99 	if (!fd->entry_to_rb)
100 		return -ENOMEM;
101 
102 	if (!HFI1_CAP_UGET_MASK(uctxt->flags, TID_UNMAP)) {
103 		fd->invalid_tid_idx = 0;
104 		fd->invalid_tids = kcalloc(uctxt->expected_count,
105 					   sizeof(*fd->invalid_tids),
106 					   GFP_KERNEL);
107 		if (!fd->invalid_tids) {
108 			kfree(fd->entry_to_rb);
109 			fd->entry_to_rb = NULL;
110 			return -ENOMEM;
111 		}
112 
113 		/*
114 		 * Register MMU notifier callbacks. If the registration
115 		 * fails, continue without TID caching for this context.
116 		 */
117 		ret = hfi1_mmu_rb_register(fd, fd->mm, &tid_rb_ops,
118 					   dd->pport->hfi1_wq,
119 					   &fd->handler);
120 		if (ret) {
121 			dd_dev_info(dd,
122 				    "Failed MMU notifier registration %d\n",
123 				    ret);
124 			ret = 0;
125 		}
126 	}
127 
128 	/*
129 	 * PSM does not have a good way to separate, count, and
130 	 * effectively enforce a limit on RcvArray entries used by
131 	 * subctxts (when context sharing is used) when TID caching
132 	 * is enabled. To help with that, we calculate a per-process
133 	 * RcvArray entry share and enforce that.
134 	 * If TID caching is not in use, PSM deals with usage on its
135 	 * own. In that case, we allow any subctxt to take all of the
136 	 * entries.
137 	 *
138 	 * Make sure that we set the tid counts only after successful
139 	 * init.
140 	 */
141 	spin_lock(&fd->tid_lock);
142 	if (uctxt->subctxt_cnt && fd->handler) {
143 		u16 remainder;
144 
145 		fd->tid_limit = uctxt->expected_count / uctxt->subctxt_cnt;
146 		remainder = uctxt->expected_count % uctxt->subctxt_cnt;
147 		if (remainder && fd->subctxt < remainder)
148 			fd->tid_limit++;
149 	} else {
150 		fd->tid_limit = uctxt->expected_count;
151 	}
152 	spin_unlock(&fd->tid_lock);
153 
154 	return ret;
155 }
156 
157 void hfi1_user_exp_rcv_free(struct hfi1_filedata *fd)
158 {
159 	struct hfi1_ctxtdata *uctxt = fd->uctxt;
160 
161 	/*
162 	 * The notifier would have been removed when the process'es mm
163 	 * was freed.
164 	 */
165 	if (fd->handler) {
166 		hfi1_mmu_rb_unregister(fd->handler);
167 	} else {
168 		if (!EXP_TID_SET_EMPTY(uctxt->tid_full_list))
169 			unlock_exp_tids(uctxt, &uctxt->tid_full_list, fd);
170 		if (!EXP_TID_SET_EMPTY(uctxt->tid_used_list))
171 			unlock_exp_tids(uctxt, &uctxt->tid_used_list, fd);
172 	}
173 
174 	kfree(fd->invalid_tids);
175 	fd->invalid_tids = NULL;
176 
177 	kfree(fd->entry_to_rb);
178 	fd->entry_to_rb = NULL;
179 }
180 
181 /**
182  * Release pinned receive buffer pages.
183  *
184  * @mapped - true if the pages have been DMA mapped. false otherwise.
185  * @idx - Index of the first page to unpin.
186  * @npages - No of pages to unpin.
187  *
188  * If the pages have been DMA mapped (indicated by mapped parameter), their
189  * info will be passed via a struct tid_rb_node. If they haven't been mapped,
190  * their info will be passed via a struct tid_user_buf.
191  */
192 static void unpin_rcv_pages(struct hfi1_filedata *fd,
193 			    struct tid_user_buf *tidbuf,
194 			    struct tid_rb_node *node,
195 			    unsigned int idx,
196 			    unsigned int npages,
197 			    bool mapped)
198 {
199 	struct page **pages;
200 	struct hfi1_devdata *dd = fd->uctxt->dd;
201 
202 	if (mapped) {
203 		pci_unmap_single(dd->pcidev, node->dma_addr,
204 				 node->mmu.len, PCI_DMA_FROMDEVICE);
205 		pages = &node->pages[idx];
206 	} else {
207 		pages = &tidbuf->pages[idx];
208 	}
209 	hfi1_release_user_pages(fd->mm, pages, npages, mapped);
210 	fd->tid_n_pinned -= npages;
211 }
212 
213 /**
214  * Pin receive buffer pages.
215  */
216 static int pin_rcv_pages(struct hfi1_filedata *fd, struct tid_user_buf *tidbuf)
217 {
218 	int pinned;
219 	unsigned int npages;
220 	unsigned long vaddr = tidbuf->vaddr;
221 	struct page **pages = NULL;
222 	struct hfi1_devdata *dd = fd->uctxt->dd;
223 
224 	/* Get the number of pages the user buffer spans */
225 	npages = num_user_pages(vaddr, tidbuf->length);
226 	if (!npages)
227 		return -EINVAL;
228 
229 	if (npages > fd->uctxt->expected_count) {
230 		dd_dev_err(dd, "Expected buffer too big\n");
231 		return -EINVAL;
232 	}
233 
234 	/* Verify that access is OK for the user buffer */
235 	if (!access_ok(VERIFY_WRITE, (void __user *)vaddr,
236 		       npages * PAGE_SIZE)) {
237 		dd_dev_err(dd, "Fail vaddr %p, %u pages, !access_ok\n",
238 			   (void *)vaddr, npages);
239 		return -EFAULT;
240 	}
241 	/* Allocate the array of struct page pointers needed for pinning */
242 	pages = kcalloc(npages, sizeof(*pages), GFP_KERNEL);
243 	if (!pages)
244 		return -ENOMEM;
245 
246 	/*
247 	 * Pin all the pages of the user buffer. If we can't pin all the
248 	 * pages, accept the amount pinned so far and program only that.
249 	 * User space knows how to deal with partially programmed buffers.
250 	 */
251 	if (!hfi1_can_pin_pages(dd, fd->mm, fd->tid_n_pinned, npages)) {
252 		kfree(pages);
253 		return -ENOMEM;
254 	}
255 
256 	pinned = hfi1_acquire_user_pages(fd->mm, vaddr, npages, true, pages);
257 	if (pinned <= 0) {
258 		kfree(pages);
259 		return pinned;
260 	}
261 	tidbuf->pages = pages;
262 	tidbuf->npages = npages;
263 	fd->tid_n_pinned += pinned;
264 	return pinned;
265 }
266 
267 /*
268  * RcvArray entry allocation for Expected Receives is done by the
269  * following algorithm:
270  *
271  * The context keeps 3 lists of groups of RcvArray entries:
272  *   1. List of empty groups - tid_group_list
273  *      This list is created during user context creation and
274  *      contains elements which describe sets (of 8) of empty
275  *      RcvArray entries.
276  *   2. List of partially used groups - tid_used_list
277  *      This list contains sets of RcvArray entries which are
278  *      not completely used up. Another mapping request could
279  *      use some of all of the remaining entries.
280  *   3. List of full groups - tid_full_list
281  *      This is the list where sets that are completely used
282  *      up go.
283  *
284  * An attempt to optimize the usage of RcvArray entries is
285  * made by finding all sets of physically contiguous pages in a
286  * user's buffer.
287  * These physically contiguous sets are further split into
288  * sizes supported by the receive engine of the HFI. The
289  * resulting sets of pages are stored in struct tid_pageset,
290  * which describes the sets as:
291  *    * .count - number of pages in this set
292  *    * .idx - starting index into struct page ** array
293  *                    of this set
294  *
295  * From this point on, the algorithm deals with the page sets
296  * described above. The number of pagesets is divided by the
297  * RcvArray group size to produce the number of full groups
298  * needed.
299  *
300  * Groups from the 3 lists are manipulated using the following
301  * rules:
302  *   1. For each set of 8 pagesets, a complete group from
303  *      tid_group_list is taken, programmed, and moved to
304  *      the tid_full_list list.
305  *   2. For all remaining pagesets:
306  *      2.1 If the tid_used_list is empty and the tid_group_list
307  *          is empty, stop processing pageset and return only
308  *          what has been programmed up to this point.
309  *      2.2 If the tid_used_list is empty and the tid_group_list
310  *          is not empty, move a group from tid_group_list to
311  *          tid_used_list.
312  *      2.3 For each group is tid_used_group, program as much as
313  *          can fit into the group. If the group becomes fully
314  *          used, move it to tid_full_list.
315  */
316 int hfi1_user_exp_rcv_setup(struct hfi1_filedata *fd,
317 			    struct hfi1_tid_info *tinfo)
318 {
319 	int ret = 0, need_group = 0, pinned;
320 	struct hfi1_ctxtdata *uctxt = fd->uctxt;
321 	struct hfi1_devdata *dd = uctxt->dd;
322 	unsigned int ngroups, pageidx = 0, pageset_count,
323 		tididx = 0, mapped, mapped_pages = 0;
324 	u32 *tidlist = NULL;
325 	struct tid_user_buf *tidbuf;
326 
327 	tidbuf = kzalloc(sizeof(*tidbuf), GFP_KERNEL);
328 	if (!tidbuf)
329 		return -ENOMEM;
330 
331 	tidbuf->vaddr = tinfo->vaddr;
332 	tidbuf->length = tinfo->length;
333 	tidbuf->psets = kcalloc(uctxt->expected_count, sizeof(*tidbuf->psets),
334 				GFP_KERNEL);
335 	if (!tidbuf->psets) {
336 		kfree(tidbuf);
337 		return -ENOMEM;
338 	}
339 
340 	pinned = pin_rcv_pages(fd, tidbuf);
341 	if (pinned <= 0) {
342 		kfree(tidbuf->psets);
343 		kfree(tidbuf);
344 		return pinned;
345 	}
346 
347 	/* Find sets of physically contiguous pages */
348 	tidbuf->n_psets = find_phys_blocks(tidbuf, pinned);
349 
350 	/*
351 	 * We don't need to access this under a lock since tid_used is per
352 	 * process and the same process cannot be in hfi1_user_exp_rcv_clear()
353 	 * and hfi1_user_exp_rcv_setup() at the same time.
354 	 */
355 	spin_lock(&fd->tid_lock);
356 	if (fd->tid_used + tidbuf->n_psets > fd->tid_limit)
357 		pageset_count = fd->tid_limit - fd->tid_used;
358 	else
359 		pageset_count = tidbuf->n_psets;
360 	spin_unlock(&fd->tid_lock);
361 
362 	if (!pageset_count)
363 		goto bail;
364 
365 	ngroups = pageset_count / dd->rcv_entries.group_size;
366 	tidlist = kcalloc(pageset_count, sizeof(*tidlist), GFP_KERNEL);
367 	if (!tidlist) {
368 		ret = -ENOMEM;
369 		goto nomem;
370 	}
371 
372 	tididx = 0;
373 
374 	/*
375 	 * From this point on, we are going to be using shared (between master
376 	 * and subcontexts) context resources. We need to take the lock.
377 	 */
378 	mutex_lock(&uctxt->exp_lock);
379 	/*
380 	 * The first step is to program the RcvArray entries which are complete
381 	 * groups.
382 	 */
383 	while (ngroups && uctxt->tid_group_list.count) {
384 		struct tid_group *grp =
385 			tid_group_pop(&uctxt->tid_group_list);
386 
387 		ret = program_rcvarray(fd, tidbuf, grp,
388 				       pageidx, dd->rcv_entries.group_size,
389 				       tidlist, &tididx, &mapped);
390 		/*
391 		 * If there was a failure to program the RcvArray
392 		 * entries for the entire group, reset the grp fields
393 		 * and add the grp back to the free group list.
394 		 */
395 		if (ret <= 0) {
396 			tid_group_add_tail(grp, &uctxt->tid_group_list);
397 			hfi1_cdbg(TID,
398 				  "Failed to program RcvArray group %d", ret);
399 			goto unlock;
400 		}
401 
402 		tid_group_add_tail(grp, &uctxt->tid_full_list);
403 		ngroups--;
404 		pageidx += ret;
405 		mapped_pages += mapped;
406 	}
407 
408 	while (pageidx < pageset_count) {
409 		struct tid_group *grp, *ptr;
410 		/*
411 		 * If we don't have any partially used tid groups, check
412 		 * if we have empty groups. If so, take one from there and
413 		 * put in the partially used list.
414 		 */
415 		if (!uctxt->tid_used_list.count || need_group) {
416 			if (!uctxt->tid_group_list.count)
417 				goto unlock;
418 
419 			grp = tid_group_pop(&uctxt->tid_group_list);
420 			tid_group_add_tail(grp, &uctxt->tid_used_list);
421 			need_group = 0;
422 		}
423 		/*
424 		 * There is an optimization opportunity here - instead of
425 		 * fitting as many page sets as we can, check for a group
426 		 * later on in the list that could fit all of them.
427 		 */
428 		list_for_each_entry_safe(grp, ptr, &uctxt->tid_used_list.list,
429 					 list) {
430 			unsigned use = min_t(unsigned, pageset_count - pageidx,
431 					     grp->size - grp->used);
432 
433 			ret = program_rcvarray(fd, tidbuf, grp,
434 					       pageidx, use, tidlist,
435 					       &tididx, &mapped);
436 			if (ret < 0) {
437 				hfi1_cdbg(TID,
438 					  "Failed to program RcvArray entries %d",
439 					  ret);
440 				ret = -EFAULT;
441 				goto unlock;
442 			} else if (ret > 0) {
443 				if (grp->used == grp->size)
444 					tid_group_move(grp,
445 						       &uctxt->tid_used_list,
446 						       &uctxt->tid_full_list);
447 				pageidx += ret;
448 				mapped_pages += mapped;
449 				need_group = 0;
450 				/* Check if we are done so we break out early */
451 				if (pageidx >= pageset_count)
452 					break;
453 			} else if (WARN_ON(ret == 0)) {
454 				/*
455 				 * If ret is 0, we did not program any entries
456 				 * into this group, which can only happen if
457 				 * we've screwed up the accounting somewhere.
458 				 * Warn and try to continue.
459 				 */
460 				need_group = 1;
461 			}
462 		}
463 	}
464 unlock:
465 	mutex_unlock(&uctxt->exp_lock);
466 nomem:
467 	hfi1_cdbg(TID, "total mapped: tidpairs:%u pages:%u (%d)", tididx,
468 		  mapped_pages, ret);
469 	if (tididx) {
470 		spin_lock(&fd->tid_lock);
471 		fd->tid_used += tididx;
472 		spin_unlock(&fd->tid_lock);
473 		tinfo->tidcnt = tididx;
474 		tinfo->length = mapped_pages * PAGE_SIZE;
475 
476 		if (copy_to_user((void __user *)(unsigned long)tinfo->tidlist,
477 				 tidlist, sizeof(tidlist[0]) * tididx)) {
478 			/*
479 			 * On failure to copy to the user level, we need to undo
480 			 * everything done so far so we don't leak resources.
481 			 */
482 			tinfo->tidlist = (unsigned long)&tidlist;
483 			hfi1_user_exp_rcv_clear(fd, tinfo);
484 			tinfo->tidlist = 0;
485 			ret = -EFAULT;
486 			goto bail;
487 		}
488 	}
489 
490 	/*
491 	 * If not everything was mapped (due to insufficient RcvArray entries,
492 	 * for example), unpin all unmapped pages so we can pin them nex time.
493 	 */
494 	if (mapped_pages != pinned)
495 		unpin_rcv_pages(fd, tidbuf, NULL, mapped_pages,
496 				(pinned - mapped_pages), false);
497 bail:
498 	kfree(tidbuf->psets);
499 	kfree(tidlist);
500 	kfree(tidbuf->pages);
501 	kfree(tidbuf);
502 	return ret > 0 ? 0 : ret;
503 }
504 
505 int hfi1_user_exp_rcv_clear(struct hfi1_filedata *fd,
506 			    struct hfi1_tid_info *tinfo)
507 {
508 	int ret = 0;
509 	struct hfi1_ctxtdata *uctxt = fd->uctxt;
510 	u32 *tidinfo;
511 	unsigned tididx;
512 
513 	if (unlikely(tinfo->tidcnt > fd->tid_used))
514 		return -EINVAL;
515 
516 	tidinfo = memdup_user((void __user *)(unsigned long)tinfo->tidlist,
517 			      sizeof(tidinfo[0]) * tinfo->tidcnt);
518 	if (IS_ERR(tidinfo))
519 		return PTR_ERR(tidinfo);
520 
521 	mutex_lock(&uctxt->exp_lock);
522 	for (tididx = 0; tididx < tinfo->tidcnt; tididx++) {
523 		ret = unprogram_rcvarray(fd, tidinfo[tididx], NULL);
524 		if (ret) {
525 			hfi1_cdbg(TID, "Failed to unprogram rcv array %d",
526 				  ret);
527 			break;
528 		}
529 	}
530 	spin_lock(&fd->tid_lock);
531 	fd->tid_used -= tididx;
532 	spin_unlock(&fd->tid_lock);
533 	tinfo->tidcnt = tididx;
534 	mutex_unlock(&uctxt->exp_lock);
535 
536 	kfree(tidinfo);
537 	return ret;
538 }
539 
540 int hfi1_user_exp_rcv_invalid(struct hfi1_filedata *fd,
541 			      struct hfi1_tid_info *tinfo)
542 {
543 	struct hfi1_ctxtdata *uctxt = fd->uctxt;
544 	unsigned long *ev = uctxt->dd->events +
545 		(((uctxt->ctxt - uctxt->dd->first_dyn_alloc_ctxt) *
546 		  HFI1_MAX_SHARED_CTXTS) + fd->subctxt);
547 	u32 *array;
548 	int ret = 0;
549 
550 	if (!fd->invalid_tids)
551 		return -EINVAL;
552 
553 	/*
554 	 * copy_to_user() can sleep, which will leave the invalid_lock
555 	 * locked and cause the MMU notifier to be blocked on the lock
556 	 * for a long time.
557 	 * Copy the data to a local buffer so we can release the lock.
558 	 */
559 	array = kcalloc(uctxt->expected_count, sizeof(*array), GFP_KERNEL);
560 	if (!array)
561 		return -EFAULT;
562 
563 	spin_lock(&fd->invalid_lock);
564 	if (fd->invalid_tid_idx) {
565 		memcpy(array, fd->invalid_tids, sizeof(*array) *
566 		       fd->invalid_tid_idx);
567 		memset(fd->invalid_tids, 0, sizeof(*fd->invalid_tids) *
568 		       fd->invalid_tid_idx);
569 		tinfo->tidcnt = fd->invalid_tid_idx;
570 		fd->invalid_tid_idx = 0;
571 		/*
572 		 * Reset the user flag while still holding the lock.
573 		 * Otherwise, PSM can miss events.
574 		 */
575 		clear_bit(_HFI1_EVENT_TID_MMU_NOTIFY_BIT, ev);
576 	} else {
577 		tinfo->tidcnt = 0;
578 	}
579 	spin_unlock(&fd->invalid_lock);
580 
581 	if (tinfo->tidcnt) {
582 		if (copy_to_user((void __user *)tinfo->tidlist,
583 				 array, sizeof(*array) * tinfo->tidcnt))
584 			ret = -EFAULT;
585 	}
586 	kfree(array);
587 
588 	return ret;
589 }
590 
591 static u32 find_phys_blocks(struct tid_user_buf *tidbuf, unsigned int npages)
592 {
593 	unsigned pagecount, pageidx, setcount = 0, i;
594 	unsigned long pfn, this_pfn;
595 	struct page **pages = tidbuf->pages;
596 	struct tid_pageset *list = tidbuf->psets;
597 
598 	if (!npages)
599 		return 0;
600 
601 	/*
602 	 * Look for sets of physically contiguous pages in the user buffer.
603 	 * This will allow us to optimize Expected RcvArray entry usage by
604 	 * using the bigger supported sizes.
605 	 */
606 	pfn = page_to_pfn(pages[0]);
607 	for (pageidx = 0, pagecount = 1, i = 1; i <= npages; i++) {
608 		this_pfn = i < npages ? page_to_pfn(pages[i]) : 0;
609 
610 		/*
611 		 * If the pfn's are not sequential, pages are not physically
612 		 * contiguous.
613 		 */
614 		if (this_pfn != ++pfn) {
615 			/*
616 			 * At this point we have to loop over the set of
617 			 * physically contiguous pages and break them down it
618 			 * sizes supported by the HW.
619 			 * There are two main constraints:
620 			 *     1. The max buffer size is MAX_EXPECTED_BUFFER.
621 			 *        If the total set size is bigger than that
622 			 *        program only a MAX_EXPECTED_BUFFER chunk.
623 			 *     2. The buffer size has to be a power of two. If
624 			 *        it is not, round down to the closes power of
625 			 *        2 and program that size.
626 			 */
627 			while (pagecount) {
628 				int maxpages = pagecount;
629 				u32 bufsize = pagecount * PAGE_SIZE;
630 
631 				if (bufsize > MAX_EXPECTED_BUFFER)
632 					maxpages =
633 						MAX_EXPECTED_BUFFER >>
634 						PAGE_SHIFT;
635 				else if (!is_power_of_2(bufsize))
636 					maxpages =
637 						rounddown_pow_of_two(bufsize) >>
638 						PAGE_SHIFT;
639 
640 				list[setcount].idx = pageidx;
641 				list[setcount].count = maxpages;
642 				pagecount -= maxpages;
643 				pageidx += maxpages;
644 				setcount++;
645 			}
646 			pageidx = i;
647 			pagecount = 1;
648 			pfn = this_pfn;
649 		} else {
650 			pagecount++;
651 		}
652 	}
653 	return setcount;
654 }
655 
656 /**
657  * program_rcvarray() - program an RcvArray group with receive buffers
658  * @fd: filedata pointer
659  * @tbuf: pointer to struct tid_user_buf that has the user buffer starting
660  *	  virtual address, buffer length, page pointers, pagesets (array of
661  *	  struct tid_pageset holding information on physically contiguous
662  *	  chunks from the user buffer), and other fields.
663  * @grp: RcvArray group
664  * @start: starting index into sets array
665  * @count: number of struct tid_pageset's to program
666  * @tidlist: the array of u32 elements when the information about the
667  *           programmed RcvArray entries is to be encoded.
668  * @tididx: starting offset into tidlist
669  * @pmapped: (output parameter) number of pages programmed into the RcvArray
670  *           entries.
671  *
672  * This function will program up to 'count' number of RcvArray entries from the
673  * group 'grp'. To make best use of write-combining writes, the function will
674  * perform writes to the unused RcvArray entries which will be ignored by the
675  * HW. Each RcvArray entry will be programmed with a physically contiguous
676  * buffer chunk from the user's virtual buffer.
677  *
678  * Return:
679  * -EINVAL if the requested count is larger than the size of the group,
680  * -ENOMEM or -EFAULT on error from set_rcvarray_entry(), or
681  * number of RcvArray entries programmed.
682  */
683 static int program_rcvarray(struct hfi1_filedata *fd, struct tid_user_buf *tbuf,
684 			    struct tid_group *grp,
685 			    unsigned int start, u16 count,
686 			    u32 *tidlist, unsigned int *tididx,
687 			    unsigned int *pmapped)
688 {
689 	struct hfi1_ctxtdata *uctxt = fd->uctxt;
690 	struct hfi1_devdata *dd = uctxt->dd;
691 	u16 idx;
692 	u32 tidinfo = 0, rcventry, useidx = 0;
693 	int mapped = 0;
694 
695 	/* Count should never be larger than the group size */
696 	if (count > grp->size)
697 		return -EINVAL;
698 
699 	/* Find the first unused entry in the group */
700 	for (idx = 0; idx < grp->size; idx++) {
701 		if (!(grp->map & (1 << idx))) {
702 			useidx = idx;
703 			break;
704 		}
705 		rcv_array_wc_fill(dd, grp->base + idx);
706 	}
707 
708 	idx = 0;
709 	while (idx < count) {
710 		u16 npages, pageidx, setidx = start + idx;
711 		int ret = 0;
712 
713 		/*
714 		 * If this entry in the group is used, move to the next one.
715 		 * If we go past the end of the group, exit the loop.
716 		 */
717 		if (useidx >= grp->size) {
718 			break;
719 		} else if (grp->map & (1 << useidx)) {
720 			rcv_array_wc_fill(dd, grp->base + useidx);
721 			useidx++;
722 			continue;
723 		}
724 
725 		rcventry = grp->base + useidx;
726 		npages = tbuf->psets[setidx].count;
727 		pageidx = tbuf->psets[setidx].idx;
728 
729 		ret = set_rcvarray_entry(fd, tbuf,
730 					 rcventry, grp, pageidx,
731 					 npages);
732 		if (ret)
733 			return ret;
734 		mapped += npages;
735 
736 		tidinfo = rcventry2tidinfo(rcventry - uctxt->expected_base) |
737 			EXP_TID_SET(LEN, npages);
738 		tidlist[(*tididx)++] = tidinfo;
739 		grp->used++;
740 		grp->map |= 1 << useidx++;
741 		idx++;
742 	}
743 
744 	/* Fill the rest of the group with "blank" writes */
745 	for (; useidx < grp->size; useidx++)
746 		rcv_array_wc_fill(dd, grp->base + useidx);
747 	*pmapped = mapped;
748 	return idx;
749 }
750 
751 static int set_rcvarray_entry(struct hfi1_filedata *fd,
752 			      struct tid_user_buf *tbuf,
753 			      u32 rcventry, struct tid_group *grp,
754 			      u16 pageidx, unsigned int npages)
755 {
756 	int ret;
757 	struct hfi1_ctxtdata *uctxt = fd->uctxt;
758 	struct tid_rb_node *node;
759 	struct hfi1_devdata *dd = uctxt->dd;
760 	dma_addr_t phys;
761 	struct page **pages = tbuf->pages + pageidx;
762 
763 	/*
764 	 * Allocate the node first so we can handle a potential
765 	 * failure before we've programmed anything.
766 	 */
767 	node = kzalloc(sizeof(*node) + (sizeof(struct page *) * npages),
768 		       GFP_KERNEL);
769 	if (!node)
770 		return -ENOMEM;
771 
772 	phys = pci_map_single(dd->pcidev,
773 			      __va(page_to_phys(pages[0])),
774 			      npages * PAGE_SIZE, PCI_DMA_FROMDEVICE);
775 	if (dma_mapping_error(&dd->pcidev->dev, phys)) {
776 		dd_dev_err(dd, "Failed to DMA map Exp Rcv pages 0x%llx\n",
777 			   phys);
778 		kfree(node);
779 		return -EFAULT;
780 	}
781 
782 	node->mmu.addr = tbuf->vaddr + (pageidx * PAGE_SIZE);
783 	node->mmu.len = npages * PAGE_SIZE;
784 	node->phys = page_to_phys(pages[0]);
785 	node->npages = npages;
786 	node->rcventry = rcventry;
787 	node->dma_addr = phys;
788 	node->grp = grp;
789 	node->freed = false;
790 	memcpy(node->pages, pages, sizeof(struct page *) * npages);
791 
792 	if (!fd->handler)
793 		ret = tid_rb_insert(fd, &node->mmu);
794 	else
795 		ret = hfi1_mmu_rb_insert(fd->handler, &node->mmu);
796 
797 	if (ret) {
798 		hfi1_cdbg(TID, "Failed to insert RB node %u 0x%lx, 0x%lx %d",
799 			  node->rcventry, node->mmu.addr, node->phys, ret);
800 		pci_unmap_single(dd->pcidev, phys, npages * PAGE_SIZE,
801 				 PCI_DMA_FROMDEVICE);
802 		kfree(node);
803 		return -EFAULT;
804 	}
805 	hfi1_put_tid(dd, rcventry, PT_EXPECTED, phys, ilog2(npages) + 1);
806 	trace_hfi1_exp_tid_reg(uctxt->ctxt, fd->subctxt, rcventry, npages,
807 			       node->mmu.addr, node->phys, phys);
808 	return 0;
809 }
810 
811 static int unprogram_rcvarray(struct hfi1_filedata *fd, u32 tidinfo,
812 			      struct tid_group **grp)
813 {
814 	struct hfi1_ctxtdata *uctxt = fd->uctxt;
815 	struct hfi1_devdata *dd = uctxt->dd;
816 	struct tid_rb_node *node;
817 	u8 tidctrl = EXP_TID_GET(tidinfo, CTRL);
818 	u32 tididx = EXP_TID_GET(tidinfo, IDX) << 1, rcventry;
819 
820 	if (tididx >= uctxt->expected_count) {
821 		dd_dev_err(dd, "Invalid RcvArray entry (%u) index for ctxt %u\n",
822 			   tididx, uctxt->ctxt);
823 		return -EINVAL;
824 	}
825 
826 	if (tidctrl == 0x3)
827 		return -EINVAL;
828 
829 	rcventry = tididx + (tidctrl - 1);
830 
831 	node = fd->entry_to_rb[rcventry];
832 	if (!node || node->rcventry != (uctxt->expected_base + rcventry))
833 		return -EBADF;
834 
835 	if (grp)
836 		*grp = node->grp;
837 
838 	if (!fd->handler)
839 		cacheless_tid_rb_remove(fd, node);
840 	else
841 		hfi1_mmu_rb_remove(fd->handler, &node->mmu);
842 
843 	return 0;
844 }
845 
846 static void clear_tid_node(struct hfi1_filedata *fd, struct tid_rb_node *node)
847 {
848 	struct hfi1_ctxtdata *uctxt = fd->uctxt;
849 	struct hfi1_devdata *dd = uctxt->dd;
850 
851 	trace_hfi1_exp_tid_unreg(uctxt->ctxt, fd->subctxt, node->rcventry,
852 				 node->npages, node->mmu.addr, node->phys,
853 				 node->dma_addr);
854 
855 	/*
856 	 * Make sure device has seen the write before we unpin the
857 	 * pages.
858 	 */
859 	hfi1_put_tid(dd, node->rcventry, PT_INVALID_FLUSH, 0, 0);
860 
861 	unpin_rcv_pages(fd, NULL, node, 0, node->npages, true);
862 
863 	node->grp->used--;
864 	node->grp->map &= ~(1 << (node->rcventry - node->grp->base));
865 
866 	if (node->grp->used == node->grp->size - 1)
867 		tid_group_move(node->grp, &uctxt->tid_full_list,
868 			       &uctxt->tid_used_list);
869 	else if (!node->grp->used)
870 		tid_group_move(node->grp, &uctxt->tid_used_list,
871 			       &uctxt->tid_group_list);
872 	kfree(node);
873 }
874 
875 /*
876  * As a simple helper for hfi1_user_exp_rcv_free, this function deals with
877  * clearing nodes in the non-cached case.
878  */
879 static void unlock_exp_tids(struct hfi1_ctxtdata *uctxt,
880 			    struct exp_tid_set *set,
881 			    struct hfi1_filedata *fd)
882 {
883 	struct tid_group *grp, *ptr;
884 	int i;
885 
886 	list_for_each_entry_safe(grp, ptr, &set->list, list) {
887 		list_del_init(&grp->list);
888 
889 		for (i = 0; i < grp->size; i++) {
890 			if (grp->map & (1 << i)) {
891 				u16 rcventry = grp->base + i;
892 				struct tid_rb_node *node;
893 
894 				node = fd->entry_to_rb[rcventry -
895 							  uctxt->expected_base];
896 				if (!node || node->rcventry != rcventry)
897 					continue;
898 
899 				cacheless_tid_rb_remove(fd, node);
900 			}
901 		}
902 	}
903 }
904 
905 /*
906  * Always return 0 from this function.  A non-zero return indicates that the
907  * remove operation will be called and that memory should be unpinned.
908  * However, the driver cannot unpin out from under PSM.  Instead, retain the
909  * memory (by returning 0) and inform PSM that the memory is going away.  PSM
910  * will call back later when it has removed the memory from its list.
911  */
912 static int tid_rb_invalidate(void *arg, struct mmu_rb_node *mnode)
913 {
914 	struct hfi1_filedata *fdata = arg;
915 	struct hfi1_ctxtdata *uctxt = fdata->uctxt;
916 	struct tid_rb_node *node =
917 		container_of(mnode, struct tid_rb_node, mmu);
918 
919 	if (node->freed)
920 		return 0;
921 
922 	trace_hfi1_exp_tid_inval(uctxt->ctxt, fdata->subctxt, node->mmu.addr,
923 				 node->rcventry, node->npages, node->dma_addr);
924 	node->freed = true;
925 
926 	spin_lock(&fdata->invalid_lock);
927 	if (fdata->invalid_tid_idx < uctxt->expected_count) {
928 		fdata->invalid_tids[fdata->invalid_tid_idx] =
929 			rcventry2tidinfo(node->rcventry - uctxt->expected_base);
930 		fdata->invalid_tids[fdata->invalid_tid_idx] |=
931 			EXP_TID_SET(LEN, node->npages);
932 		if (!fdata->invalid_tid_idx) {
933 			unsigned long *ev;
934 
935 			/*
936 			 * hfi1_set_uevent_bits() sets a user event flag
937 			 * for all processes. Because calling into the
938 			 * driver to process TID cache invalidations is
939 			 * expensive and TID cache invalidations are
940 			 * handled on a per-process basis, we can
941 			 * optimize this to set the flag only for the
942 			 * process in question.
943 			 */
944 			ev = uctxt->dd->events +
945 			  (((uctxt->ctxt - uctxt->dd->first_dyn_alloc_ctxt) *
946 			    HFI1_MAX_SHARED_CTXTS) + fdata->subctxt);
947 			set_bit(_HFI1_EVENT_TID_MMU_NOTIFY_BIT, ev);
948 		}
949 		fdata->invalid_tid_idx++;
950 	}
951 	spin_unlock(&fdata->invalid_lock);
952 	return 0;
953 }
954 
955 static int tid_rb_insert(void *arg, struct mmu_rb_node *node)
956 {
957 	struct hfi1_filedata *fdata = arg;
958 	struct tid_rb_node *tnode =
959 		container_of(node, struct tid_rb_node, mmu);
960 	u32 base = fdata->uctxt->expected_base;
961 
962 	fdata->entry_to_rb[tnode->rcventry - base] = tnode;
963 	return 0;
964 }
965 
966 static void cacheless_tid_rb_remove(struct hfi1_filedata *fdata,
967 				    struct tid_rb_node *tnode)
968 {
969 	u32 base = fdata->uctxt->expected_base;
970 
971 	fdata->entry_to_rb[tnode->rcventry - base] = NULL;
972 	clear_tid_node(fdata, tnode);
973 }
974 
975 static void tid_rb_remove(void *arg, struct mmu_rb_node *node)
976 {
977 	struct hfi1_filedata *fdata = arg;
978 	struct tid_rb_node *tnode =
979 		container_of(node, struct tid_rb_node, mmu);
980 
981 	cacheless_tid_rb_remove(fdata, tnode);
982 }
983