xref: /linux/drivers/mmc/core/queue.c (revision d354a6f150d873440975263530a2e42121d50a51) 
1 /*
2  *  Copyright (C) 2003 Russell King, All Rights Reserved.
3  *  Copyright 2006-2007 Pierre Ossman
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  *
9  */
10 #include <linux/slab.h>
11 #include <linux/module.h>
12 #include <linux/blkdev.h>
13 #include <linux/freezer.h>
14 #include <linux/kthread.h>
15 #include <linux/scatterlist.h>
16 #include <linux/dma-mapping.h>
17 
18 #include <linux/mmc/card.h>
19 #include <linux/mmc/host.h>
20 
21 #include "queue.h"
22 #include "block.h"
23 #include "core.h"
24 #include "card.h"
25 
26 #define MMC_QUEUE_BOUNCESZ	65536
27 
28 /*
29  * Prepare a MMC request. This just filters out odd stuff.
30  */
31 static int mmc_prep_request(struct request_queue *q, struct request *req)
32 {
33 	struct mmc_queue *mq = q->queuedata;
34 
35 	if (mq && (mmc_card_removed(mq->card) || mmc_access_rpmb(mq)))
36 		return BLKPREP_KILL;
37 
38 	req->rq_flags |= RQF_DONTPREP;
39 
40 	return BLKPREP_OK;
41 }
42 
43 static int mmc_queue_thread(void *d)
44 {
45 	struct mmc_queue *mq = d;
46 	struct request_queue *q = mq->queue;
47 	struct mmc_context_info *cntx = &mq->card->host->context_info;
48 
49 	current->flags |= PF_MEMALLOC;
50 
51 	down(&mq->thread_sem);
52 	do {
53 		struct request *req;
54 
55 		spin_lock_irq(q->queue_lock);
56 		set_current_state(TASK_INTERRUPTIBLE);
57 		req = blk_fetch_request(q);
58 		mq->asleep = false;
59 		cntx->is_waiting_last_req = false;
60 		cntx->is_new_req = false;
61 		if (!req) {
62 			/*
63 			 * Dispatch queue is empty so set flags for
64 			 * mmc_request_fn() to wake us up.
65 			 */
66 			if (mq->qcnt)
67 				cntx->is_waiting_last_req = true;
68 			else
69 				mq->asleep = true;
70 		}
71 		spin_unlock_irq(q->queue_lock);
72 
73 		if (req || mq->qcnt) {
74 			set_current_state(TASK_RUNNING);
75 			mmc_blk_issue_rq(mq, req);
76 			cond_resched();
77 		} else {
78 			if (kthread_should_stop()) {
79 				set_current_state(TASK_RUNNING);
80 				break;
81 			}
82 			up(&mq->thread_sem);
83 			schedule();
84 			down(&mq->thread_sem);
85 		}
86 	} while (1);
87 	up(&mq->thread_sem);
88 
89 	return 0;
90 }
91 
92 /*
93  * Generic MMC request handler.  This is called for any queue on a
94  * particular host.  When the host is not busy, we look for a request
95  * on any queue on this host, and attempt to issue it.  This may
96  * not be the queue we were asked to process.
97  */
98 static void mmc_request_fn(struct request_queue *q)
99 {
100 	struct mmc_queue *mq = q->queuedata;
101 	struct request *req;
102 	struct mmc_context_info *cntx;
103 
104 	if (!mq) {
105 		while ((req = blk_fetch_request(q)) != NULL) {
106 			req->rq_flags |= RQF_QUIET;
107 			__blk_end_request_all(req, BLK_STS_IOERR);
108 		}
109 		return;
110 	}
111 
112 	cntx = &mq->card->host->context_info;
113 
114 	if (cntx->is_waiting_last_req) {
115 		cntx->is_new_req = true;
116 		wake_up_interruptible(&cntx->wait);
117 	}
118 
119 	if (mq->asleep)
120 		wake_up_process(mq->thread);
121 }
122 
123 static struct scatterlist *mmc_alloc_sg(int sg_len, gfp_t gfp)
124 {
125 	struct scatterlist *sg;
126 
127 	sg = kmalloc_array(sg_len, sizeof(*sg), gfp);
128 	if (sg)
129 		sg_init_table(sg, sg_len);
130 
131 	return sg;
132 }
133 
134 static void mmc_queue_setup_discard(struct request_queue *q,
135 				    struct mmc_card *card)
136 {
137 	unsigned max_discard;
138 
139 	max_discard = mmc_calc_max_discard(card);
140 	if (!max_discard)
141 		return;
142 
143 	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
144 	blk_queue_max_discard_sectors(q, max_discard);
145 	q->limits.discard_granularity = card->pref_erase << 9;
146 	/* granularity must not be greater than max. discard */
147 	if (card->pref_erase > max_discard)
148 		q->limits.discard_granularity = 0;
149 	if (mmc_can_secure_erase_trim(card))
150 		queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, q);
151 }
152 
153 static unsigned int mmc_queue_calc_bouncesz(struct mmc_host *host)
154 {
155 	unsigned int bouncesz = MMC_QUEUE_BOUNCESZ;
156 
157 	if (host->max_segs != 1 || (host->caps & MMC_CAP_NO_BOUNCE_BUFF))
158 		return 0;
159 
160 	if (bouncesz > host->max_req_size)
161 		bouncesz = host->max_req_size;
162 	if (bouncesz > host->max_seg_size)
163 		bouncesz = host->max_seg_size;
164 	if (bouncesz > host->max_blk_count * 512)
165 		bouncesz = host->max_blk_count * 512;
166 
167 	if (bouncesz <= 512)
168 		return 0;
169 
170 	return bouncesz;
171 }
172 
173 /**
174  * mmc_init_request() - initialize the MMC-specific per-request data
175  * @q: the request queue
176  * @req: the request
177  * @gfp: memory allocation policy
178  */
179 static int mmc_init_request(struct request_queue *q, struct request *req,
180 			    gfp_t gfp)
181 {
182 	struct mmc_queue_req *mq_rq = req_to_mmc_queue_req(req);
183 	struct mmc_queue *mq = q->queuedata;
184 	struct mmc_card *card = mq->card;
185 	struct mmc_host *host = card->host;
186 
187 	if (card->bouncesz) {
188 		mq_rq->bounce_buf = kmalloc(card->bouncesz, gfp);
189 		if (!mq_rq->bounce_buf)
190 			return -ENOMEM;
191 		if (card->bouncesz > 512) {
192 			mq_rq->sg = mmc_alloc_sg(1, gfp);
193 			if (!mq_rq->sg)
194 				return -ENOMEM;
195 			mq_rq->bounce_sg = mmc_alloc_sg(card->bouncesz / 512,
196 							gfp);
197 			if (!mq_rq->bounce_sg)
198 				return -ENOMEM;
199 		}
200 	} else {
201 		mq_rq->bounce_buf = NULL;
202 		mq_rq->bounce_sg = NULL;
203 		mq_rq->sg = mmc_alloc_sg(host->max_segs, gfp);
204 		if (!mq_rq->sg)
205 			return -ENOMEM;
206 	}
207 
208 	return 0;
209 }
210 
211 static void mmc_exit_request(struct request_queue *q, struct request *req)
212 {
213 	struct mmc_queue_req *mq_rq = req_to_mmc_queue_req(req);
214 
215 	/* It is OK to kfree(NULL) so this will be smooth */
216 	kfree(mq_rq->bounce_sg);
217 	mq_rq->bounce_sg = NULL;
218 
219 	kfree(mq_rq->bounce_buf);
220 	mq_rq->bounce_buf = NULL;
221 
222 	kfree(mq_rq->sg);
223 	mq_rq->sg = NULL;
224 }
225 
226 /**
227  * mmc_init_queue - initialise a queue structure.
228  * @mq: mmc queue
229  * @card: mmc card to attach this queue
230  * @lock: queue lock
231  * @subname: partition subname
232  *
233  * Initialise a MMC card request queue.
234  */
235 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
236 		   spinlock_t *lock, const char *subname)
237 {
238 	struct mmc_host *host = card->host;
239 	u64 limit = BLK_BOUNCE_HIGH;
240 	int ret = -ENOMEM;
241 
242 	if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
243 		limit = (u64)dma_max_pfn(mmc_dev(host)) << PAGE_SHIFT;
244 
245 	/*
246 	 * mmc_init_request() depends on card->bouncesz so it must be calculated
247 	 * before blk_init_allocated_queue() starts allocating requests.
248 	 */
249 	card->bouncesz = mmc_queue_calc_bouncesz(host);
250 
251 	mq->card = card;
252 	mq->queue = blk_alloc_queue(GFP_KERNEL);
253 	if (!mq->queue)
254 		return -ENOMEM;
255 	mq->queue->queue_lock = lock;
256 	mq->queue->request_fn = mmc_request_fn;
257 	mq->queue->init_rq_fn = mmc_init_request;
258 	mq->queue->exit_rq_fn = mmc_exit_request;
259 	mq->queue->cmd_size = sizeof(struct mmc_queue_req);
260 	mq->queue->queuedata = mq;
261 	mq->qcnt = 0;
262 	ret = blk_init_allocated_queue(mq->queue);
263 	if (ret) {
264 		blk_cleanup_queue(mq->queue);
265 		return ret;
266 	}
267 
268 	blk_queue_prep_rq(mq->queue, mmc_prep_request);
269 	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
270 	queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, mq->queue);
271 	if (mmc_can_erase(card))
272 		mmc_queue_setup_discard(mq->queue, card);
273 
274 	if (card->bouncesz) {
275 		blk_queue_max_hw_sectors(mq->queue, card->bouncesz / 512);
276 		blk_queue_max_segments(mq->queue, card->bouncesz / 512);
277 		blk_queue_max_segment_size(mq->queue, card->bouncesz);
278 	} else {
279 		blk_queue_bounce_limit(mq->queue, limit);
280 		blk_queue_max_hw_sectors(mq->queue,
281 			min(host->max_blk_count, host->max_req_size / 512));
282 		blk_queue_max_segments(mq->queue, host->max_segs);
283 		blk_queue_max_segment_size(mq->queue, host->max_seg_size);
284 	}
285 
286 	sema_init(&mq->thread_sem, 1);
287 
288 	mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
289 		host->index, subname ? subname : "");
290 
291 	if (IS_ERR(mq->thread)) {
292 		ret = PTR_ERR(mq->thread);
293 		goto cleanup_queue;
294 	}
295 
296 	return 0;
297 
298 cleanup_queue:
299 	blk_cleanup_queue(mq->queue);
300 	return ret;
301 }
302 
303 void mmc_cleanup_queue(struct mmc_queue *mq)
304 {
305 	struct request_queue *q = mq->queue;
306 	unsigned long flags;
307 
308 	/* Make sure the queue isn't suspended, as that will deadlock */
309 	mmc_queue_resume(mq);
310 
311 	/* Then terminate our worker thread */
312 	kthread_stop(mq->thread);
313 
314 	/* Empty the queue */
315 	spin_lock_irqsave(q->queue_lock, flags);
316 	q->queuedata = NULL;
317 	blk_start_queue(q);
318 	spin_unlock_irqrestore(q->queue_lock, flags);
319 
320 	mq->card = NULL;
321 }
322 EXPORT_SYMBOL(mmc_cleanup_queue);
323 
324 /**
325  * mmc_queue_suspend - suspend a MMC request queue
326  * @mq: MMC queue to suspend
327  *
328  * Stop the block request queue, and wait for our thread to
329  * complete any outstanding requests.  This ensures that we
330  * won't suspend while a request is being processed.
331  */
332 void mmc_queue_suspend(struct mmc_queue *mq)
333 {
334 	struct request_queue *q = mq->queue;
335 	unsigned long flags;
336 
337 	if (!mq->suspended) {
338 		mq->suspended |= true;
339 
340 		spin_lock_irqsave(q->queue_lock, flags);
341 		blk_stop_queue(q);
342 		spin_unlock_irqrestore(q->queue_lock, flags);
343 
344 		down(&mq->thread_sem);
345 	}
346 }
347 
348 /**
349  * mmc_queue_resume - resume a previously suspended MMC request queue
350  * @mq: MMC queue to resume
351  */
352 void mmc_queue_resume(struct mmc_queue *mq)
353 {
354 	struct request_queue *q = mq->queue;
355 	unsigned long flags;
356 
357 	if (mq->suspended) {
358 		mq->suspended = false;
359 
360 		up(&mq->thread_sem);
361 
362 		spin_lock_irqsave(q->queue_lock, flags);
363 		blk_start_queue(q);
364 		spin_unlock_irqrestore(q->queue_lock, flags);
365 	}
366 }
367 
368 /*
369  * Prepare the sg list(s) to be handed of to the host driver
370  */
371 unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq)
372 {
373 	unsigned int sg_len;
374 	size_t buflen;
375 	struct scatterlist *sg;
376 	struct request *req = mmc_queue_req_to_req(mqrq);
377 	int i;
378 
379 	if (!mqrq->bounce_buf)
380 		return blk_rq_map_sg(mq->queue, req, mqrq->sg);
381 
382 	sg_len = blk_rq_map_sg(mq->queue, req, mqrq->bounce_sg);
383 
384 	mqrq->bounce_sg_len = sg_len;
385 
386 	buflen = 0;
387 	for_each_sg(mqrq->bounce_sg, sg, sg_len, i)
388 		buflen += sg->length;
389 
390 	sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);
391 
392 	return 1;
393 }
394 
395 /*
396  * If writing, bounce the data to the buffer before the request
397  * is sent to the host driver
398  */
399 void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq)
400 {
401 	if (!mqrq->bounce_buf)
402 		return;
403 
404 	if (rq_data_dir(mmc_queue_req_to_req(mqrq)) != WRITE)
405 		return;
406 
407 	sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
408 		mqrq->bounce_buf, mqrq->sg[0].length);
409 }
410 
411 /*
412  * If reading, bounce the data from the buffer after the request
413  * has been handled by the host driver
414  */
415 void mmc_queue_bounce_post(struct mmc_queue_req *mqrq)
416 {
417 	if (!mqrq->bounce_buf)
418 		return;
419 
420 	if (rq_data_dir(mmc_queue_req_to_req(mqrq)) != READ)
421 		return;
422 
423 	sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len,
424 		mqrq->bounce_buf, mqrq->sg[0].length);
425 }
426