1/*-
2 * SPDX-License-Identifier: BSD-2-Clause OR GPL-2.0
3 *
4 * Copyright (c) 2004 Topspin Communications.  All rights reserved.
5 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
6 *
7 * This software is available to you under a choice of one of two
8 * licenses.  You may choose to be licensed under the terms of the GNU
9 * General Public License (GPL) Version 2, available from the file
10 * COPYING in the main directory of this source tree, or the
11 * OpenIB.org BSD license below:
12 *
13 *     Redistribution and use in source and binary forms, with or
14 *     without modification, are permitted provided that the following
15 *     conditions are met:
16 *
17 *      - Redistributions of source code must retain the above
18 *        copyright notice, this list of conditions and the following
19 *        disclaimer.
20 *
21 *      - Redistributions in binary form must reproduce the above
22 *        copyright notice, this list of conditions and the following
23 *        disclaimer in the documentation and/or other materials
24 *        provided with the distribution.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
27 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
28 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
29 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
30 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
31 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
32 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
33 * SOFTWARE.
34 */
35
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD$");
38
39#include <linux/errno.h>
40#include <linux/spinlock.h>
41#include <linux/slab.h>
42#include <linux/jhash.h>
43#include <linux/kthread.h>
44#include <linux/wait.h>
45
46#include <rdma/ib_fmr_pool.h>
47
48#include "core_priv.h"
49
50#define PFX "fmr_pool: "
51
52enum {
53	IB_FMR_MAX_REMAPS = 32,
54
55	IB_FMR_HASH_BITS  = 8,
56	IB_FMR_HASH_SIZE  = 1 << IB_FMR_HASH_BITS,
57	IB_FMR_HASH_MASK  = IB_FMR_HASH_SIZE - 1
58};
59
60/*
61 * If an FMR is not in use, then the list member will point to either
62 * its pool's free_list (if the FMR can be mapped again; that is,
63 * remap_count < pool->max_remaps) or its pool's dirty_list (if the
64 * FMR needs to be unmapped before being remapped).  In either of
65 * these cases it is a bug if the ref_count is not 0.  In other words,
66 * if ref_count is > 0, then the list member must not be linked into
67 * either free_list or dirty_list.
68 *
69 * The cache_node member is used to link the FMR into a cache bucket
70 * (if caching is enabled).  This is independent of the reference
71 * count of the FMR.  When a valid FMR is released, its ref_count is
72 * decremented, and if ref_count reaches 0, the FMR is placed in
73 * either free_list or dirty_list as appropriate.  However, it is not
74 * removed from the cache and may be "revived" if a call to
75 * ib_fmr_register_physical() occurs before the FMR is remapped.  In
76 * this case we just increment the ref_count and remove the FMR from
77 * free_list/dirty_list.
78 *
79 * Before we remap an FMR from free_list, we remove it from the cache
80 * (to prevent another user from obtaining a stale FMR).  When an FMR
81 * is released, we add it to the tail of the free list, so that our
82 * cache eviction policy is "least recently used."
83 *
84 * All manipulation of ref_count, list and cache_node is protected by
85 * pool_lock to maintain consistency.
86 */
87
88struct ib_fmr_pool {
89	spinlock_t                pool_lock;
90
91	int                       pool_size;
92	int                       max_pages;
93	int			  max_remaps;
94	int                       dirty_watermark;
95	int                       dirty_len;
96	struct list_head          free_list;
97	struct list_head          dirty_list;
98	struct hlist_head        *cache_bucket;
99
100	void                     (*flush_function)(struct ib_fmr_pool *pool,
101						   void *              arg);
102	void                     *flush_arg;
103
104	struct task_struct       *thread;
105
106	atomic_t                  req_ser;
107	atomic_t                  flush_ser;
108
109	wait_queue_head_t         force_wait;
110};
111
112static inline u32 ib_fmr_hash(u64 first_page)
113{
114	return jhash_2words((u32) first_page, (u32) (first_page >> 32), 0) &
115		(IB_FMR_HASH_SIZE - 1);
116}
117
118/* Caller must hold pool_lock */
119static inline struct ib_pool_fmr *ib_fmr_cache_lookup(struct ib_fmr_pool *pool,
120						      u64 *page_list,
121						      int  page_list_len,
122						      u64  io_virtual_address)
123{
124	struct hlist_head *bucket;
125	struct ib_pool_fmr *fmr;
126
127	if (!pool->cache_bucket)
128		return NULL;
129
130	bucket = pool->cache_bucket + ib_fmr_hash(*page_list);
131
132	hlist_for_each_entry(fmr, bucket, cache_node)
133		if (io_virtual_address == fmr->io_virtual_address &&
134		    page_list_len      == fmr->page_list_len      &&
135		    !memcmp(page_list, fmr->page_list,
136			    page_list_len * sizeof *page_list))
137			return fmr;
138
139	return NULL;
140}
141
142static void ib_fmr_batch_release(struct ib_fmr_pool *pool)
143{
144	int                 ret;
145	struct ib_pool_fmr *fmr;
146	LIST_HEAD(unmap_list);
147	LIST_HEAD(fmr_list);
148
149	spin_lock_irq(&pool->pool_lock);
150
151	list_for_each_entry(fmr, &pool->dirty_list, list) {
152		hlist_del_init(&fmr->cache_node);
153		fmr->remap_count = 0;
154		list_add_tail(&fmr->fmr->list, &fmr_list);
155
156#ifdef DEBUG
157		if (fmr->ref_count !=0) {
158			pr_warn(PFX "Unmapping FMR %p with ref count %d\n",
159				fmr, fmr->ref_count);
160		}
161#endif
162	}
163
164	list_splice_init(&pool->dirty_list, &unmap_list);
165	pool->dirty_len = 0;
166
167	spin_unlock_irq(&pool->pool_lock);
168
169	if (list_empty(&unmap_list)) {
170		return;
171	}
172
173	ret = ib_unmap_fmr(&fmr_list);
174	if (ret)
175		pr_warn(PFX "ib_unmap_fmr returned %d\n", ret);
176
177	spin_lock_irq(&pool->pool_lock);
178	list_splice(&unmap_list, &pool->free_list);
179	spin_unlock_irq(&pool->pool_lock);
180}
181
182static int ib_fmr_cleanup_thread(void *pool_ptr)
183{
184	struct ib_fmr_pool *pool = pool_ptr;
185
186	do {
187		if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) < 0) {
188			ib_fmr_batch_release(pool);
189
190			atomic_inc(&pool->flush_ser);
191			wake_up_interruptible(&pool->force_wait);
192
193			if (pool->flush_function)
194				pool->flush_function(pool, pool->flush_arg);
195		}
196
197		set_current_state(TASK_INTERRUPTIBLE);
198		if (atomic_read(&pool->flush_ser) - atomic_read(&pool->req_ser) >= 0 &&
199		    !kthread_should_stop())
200			schedule();
201		__set_current_state(TASK_RUNNING);
202	} while (!kthread_should_stop());
203
204	return 0;
205}
206
207/**
208 * ib_create_fmr_pool - Create an FMR pool
209 * @pd:Protection domain for FMRs
210 * @params:FMR pool parameters
211 *
212 * Create a pool of FMRs.  Return value is pointer to new pool or
213 * error code if creation failed.
214 */
215struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd             *pd,
216				       struct ib_fmr_pool_param *params)
217{
218	struct ib_device   *device;
219	struct ib_fmr_pool *pool;
220	int i;
221	int ret;
222	int max_remaps;
223
224	if (!params)
225		return ERR_PTR(-EINVAL);
226
227	device = pd->device;
228	if (!device->alloc_fmr    || !device->dealloc_fmr  ||
229	    !device->map_phys_fmr || !device->unmap_fmr) {
230		pr_info(PFX "Device %s does not support FMRs\n", device->name);
231		return ERR_PTR(-ENOSYS);
232	}
233
234	if (!device->attrs.max_map_per_fmr)
235		max_remaps = IB_FMR_MAX_REMAPS;
236	else
237		max_remaps = device->attrs.max_map_per_fmr;
238
239	pool = kmalloc(sizeof *pool, GFP_KERNEL);
240	if (!pool)
241		return ERR_PTR(-ENOMEM);
242
243	pool->cache_bucket   = NULL;
244	pool->flush_function = params->flush_function;
245	pool->flush_arg      = params->flush_arg;
246
247	INIT_LIST_HEAD(&pool->free_list);
248	INIT_LIST_HEAD(&pool->dirty_list);
249
250	if (params->cache) {
251		pool->cache_bucket =
252			kmalloc(IB_FMR_HASH_SIZE * sizeof *pool->cache_bucket,
253				GFP_KERNEL);
254		if (!pool->cache_bucket) {
255			pr_warn(PFX "Failed to allocate cache in pool\n");
256			ret = -ENOMEM;
257			goto out_free_pool;
258		}
259
260		for (i = 0; i < IB_FMR_HASH_SIZE; ++i)
261			INIT_HLIST_HEAD(pool->cache_bucket + i);
262	}
263
264	pool->pool_size       = 0;
265	pool->max_pages       = params->max_pages_per_fmr;
266	pool->max_remaps      = max_remaps;
267	pool->dirty_watermark = params->dirty_watermark;
268	pool->dirty_len       = 0;
269	spin_lock_init(&pool->pool_lock);
270	atomic_set(&pool->req_ser,   0);
271	atomic_set(&pool->flush_ser, 0);
272	init_waitqueue_head(&pool->force_wait);
273
274	pool->thread = kthread_run(ib_fmr_cleanup_thread,
275				   pool,
276				   "ib_fmr(%s)",
277				   device->name);
278	if (IS_ERR(pool->thread)) {
279		pr_warn(PFX "couldn't start cleanup thread\n");
280		ret = PTR_ERR(pool->thread);
281		goto out_free_pool;
282	}
283
284	{
285		struct ib_pool_fmr *fmr;
286		struct ib_fmr_attr fmr_attr = {
287			.max_pages  = params->max_pages_per_fmr,
288			.max_maps   = pool->max_remaps,
289			.page_shift = params->page_shift
290		};
291		int bytes_per_fmr = sizeof *fmr;
292
293		if (pool->cache_bucket)
294			bytes_per_fmr += params->max_pages_per_fmr * sizeof (u64);
295
296		for (i = 0; i < params->pool_size; ++i) {
297			fmr = kmalloc(bytes_per_fmr, GFP_KERNEL);
298			if (!fmr)
299				goto out_fail;
300
301			fmr->pool             = pool;
302			fmr->remap_count      = 0;
303			fmr->ref_count        = 0;
304			INIT_HLIST_NODE(&fmr->cache_node);
305
306			fmr->fmr = ib_alloc_fmr(pd, params->access, &fmr_attr);
307			if (IS_ERR(fmr->fmr)) {
308				pr_warn(PFX "fmr_create failed for FMR %d\n",
309					i);
310				kfree(fmr);
311				goto out_fail;
312			}
313
314			list_add_tail(&fmr->list, &pool->free_list);
315			++pool->pool_size;
316		}
317	}
318
319	return pool;
320
321 out_free_pool:
322	kfree(pool->cache_bucket);
323	kfree(pool);
324
325	return ERR_PTR(ret);
326
327 out_fail:
328	ib_destroy_fmr_pool(pool);
329
330	return ERR_PTR(-ENOMEM);
331}
332EXPORT_SYMBOL(ib_create_fmr_pool);
333
334/**
335 * ib_destroy_fmr_pool - Free FMR pool
336 * @pool:FMR pool to free
337 *
338 * Destroy an FMR pool and free all associated resources.
339 */
340void ib_destroy_fmr_pool(struct ib_fmr_pool *pool)
341{
342	struct ib_pool_fmr *fmr;
343	struct ib_pool_fmr *tmp;
344	LIST_HEAD(fmr_list);
345	int                 i;
346
347	kthread_stop(pool->thread);
348	ib_fmr_batch_release(pool);
349
350	i = 0;
351	list_for_each_entry_safe(fmr, tmp, &pool->free_list, list) {
352		if (fmr->remap_count) {
353			INIT_LIST_HEAD(&fmr_list);
354			list_add_tail(&fmr->fmr->list, &fmr_list);
355			ib_unmap_fmr(&fmr_list);
356		}
357		ib_dealloc_fmr(fmr->fmr);
358		list_del(&fmr->list);
359		kfree(fmr);
360		++i;
361	}
362
363	if (i < pool->pool_size)
364		pr_warn(PFX "pool still has %d regions registered\n",
365			pool->pool_size - i);
366
367	kfree(pool->cache_bucket);
368	kfree(pool);
369}
370EXPORT_SYMBOL(ib_destroy_fmr_pool);
371
372/**
373 * ib_flush_fmr_pool - Invalidate all unmapped FMRs
374 * @pool:FMR pool to flush
375 *
376 * Ensure that all unmapped FMRs are fully invalidated.
377 */
378int ib_flush_fmr_pool(struct ib_fmr_pool *pool)
379{
380	int serial;
381	struct ib_pool_fmr *fmr, *next;
382
383	/*
384	 * The free_list holds FMRs that may have been used
385	 * but have not been remapped enough times to be dirty.
386	 * Put them on the dirty list now so that the cleanup
387	 * thread will reap them too.
388	 */
389	spin_lock_irq(&pool->pool_lock);
390	list_for_each_entry_safe(fmr, next, &pool->free_list, list) {
391		if (fmr->remap_count > 0)
392			list_move(&fmr->list, &pool->dirty_list);
393	}
394	spin_unlock_irq(&pool->pool_lock);
395
396	serial = atomic_inc_return(&pool->req_ser);
397	wake_up_process(pool->thread);
398
399	if (wait_event_interruptible(pool->force_wait,
400				     atomic_read(&pool->flush_ser) - serial >= 0))
401		return -EINTR;
402
403	return 0;
404}
405EXPORT_SYMBOL(ib_flush_fmr_pool);
406
407/**
408 * ib_fmr_pool_map_phys -
409 * @pool:FMR pool to allocate FMR from
410 * @page_list:List of pages to map
411 * @list_len:Number of pages in @page_list
412 * @io_virtual_address:I/O virtual address for new FMR
413 *
414 * Map an FMR from an FMR pool.
415 */
416struct ib_pool_fmr *ib_fmr_pool_map_phys(struct ib_fmr_pool *pool_handle,
417					 u64                *page_list,
418					 int                 list_len,
419					 u64                 io_virtual_address)
420{
421	struct ib_fmr_pool *pool = pool_handle;
422	struct ib_pool_fmr *fmr;
423	unsigned long       flags;
424	int                 result;
425
426	if (list_len < 1 || list_len > pool->max_pages)
427		return ERR_PTR(-EINVAL);
428
429	spin_lock_irqsave(&pool->pool_lock, flags);
430	fmr = ib_fmr_cache_lookup(pool,
431				  page_list,
432				  list_len,
433				  io_virtual_address);
434	if (fmr) {
435		/* found in cache */
436		++fmr->ref_count;
437		if (fmr->ref_count == 1) {
438			list_del(&fmr->list);
439		}
440
441		spin_unlock_irqrestore(&pool->pool_lock, flags);
442
443		return fmr;
444	}
445
446	if (list_empty(&pool->free_list)) {
447		spin_unlock_irqrestore(&pool->pool_lock, flags);
448		return ERR_PTR(-EAGAIN);
449	}
450
451	fmr = list_entry(pool->free_list.next, struct ib_pool_fmr, list);
452	list_del(&fmr->list);
453	hlist_del_init(&fmr->cache_node);
454	spin_unlock_irqrestore(&pool->pool_lock, flags);
455
456	result = ib_map_phys_fmr(fmr->fmr, page_list, list_len,
457				 io_virtual_address);
458
459	if (result) {
460		spin_lock_irqsave(&pool->pool_lock, flags);
461		list_add(&fmr->list, &pool->free_list);
462		spin_unlock_irqrestore(&pool->pool_lock, flags);
463
464		pr_warn(PFX "fmr_map returns %d\n", result);
465
466		return ERR_PTR(result);
467	}
468
469	++fmr->remap_count;
470	fmr->ref_count = 1;
471
472	if (pool->cache_bucket) {
473		fmr->io_virtual_address = io_virtual_address;
474		fmr->page_list_len      = list_len;
475		memcpy(fmr->page_list, page_list, list_len * sizeof(*page_list));
476
477		spin_lock_irqsave(&pool->pool_lock, flags);
478		hlist_add_head(&fmr->cache_node,
479			       pool->cache_bucket + ib_fmr_hash(fmr->page_list[0]));
480		spin_unlock_irqrestore(&pool->pool_lock, flags);
481	}
482
483	return fmr;
484}
485EXPORT_SYMBOL(ib_fmr_pool_map_phys);
486
487/**
488 * ib_fmr_pool_unmap - Unmap FMR
489 * @fmr:FMR to unmap
490 *
491 * Unmap an FMR.  The FMR mapping may remain valid until the FMR is
492 * reused (or until ib_flush_fmr_pool() is called).
493 */
494int ib_fmr_pool_unmap(struct ib_pool_fmr *fmr)
495{
496	struct ib_fmr_pool *pool;
497	unsigned long flags;
498
499	pool = fmr->pool;
500
501	spin_lock_irqsave(&pool->pool_lock, flags);
502
503	--fmr->ref_count;
504	if (!fmr->ref_count) {
505		if (fmr->remap_count < pool->max_remaps) {
506			list_add_tail(&fmr->list, &pool->free_list);
507		} else {
508			list_add_tail(&fmr->list, &pool->dirty_list);
509			if (++pool->dirty_len >= pool->dirty_watermark) {
510				atomic_inc(&pool->req_ser);
511				wake_up_process(pool->thread);
512			}
513		}
514	}
515
516#ifdef DEBUG
517	if (fmr->ref_count < 0)
518		pr_warn(PFX "FMR %p has ref count %d < 0\n",
519			fmr, fmr->ref_count);
520#endif
521
522	spin_unlock_irqrestore(&pool->pool_lock, flags);
523
524	return 0;
525}
526EXPORT_SYMBOL(ib_fmr_pool_unmap);
527