V4L/DVB (9997): gspca - main: Don't lock the kernel on ioctl.
[linux-2.6] / drivers / mmc / card / queue.c
1 /*
2  *  linux/drivers/mmc/card/queue.c
3  *
4  *  Copyright (C) 2003 Russell King, All Rights Reserved.
5  *  Copyright 2006-2007 Pierre Ossman
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  *
11  */
12 #include <linux/module.h>
13 #include <linux/blkdev.h>
14 #include <linux/freezer.h>
15 #include <linux/kthread.h>
16 #include <linux/scatterlist.h>
17
18 #include <linux/mmc/card.h>
19 #include <linux/mmc/host.h>
20 #include "queue.h"
21
22 #define MMC_QUEUE_BOUNCESZ      65536
23
24 #define MMC_QUEUE_SUSPENDED     (1 << 0)
25
26 /*
27  * Prepare a MMC request. This just filters out odd stuff.
28  */
29 static int mmc_prep_request(struct request_queue *q, struct request *req)
30 {
31         /*
32          * We only like normal block requests.
33          */
34         if (!blk_fs_request(req)) {
35                 blk_dump_rq_flags(req, "MMC bad request");
36                 return BLKPREP_KILL;
37         }
38
39         req->cmd_flags |= REQ_DONTPREP;
40
41         return BLKPREP_OK;
42 }
43
44 static int mmc_queue_thread(void *d)
45 {
46         struct mmc_queue *mq = d;
47         struct request_queue *q = mq->queue;
48
49         current->flags |= PF_MEMALLOC;
50
51         down(&mq->thread_sem);
52         do {
53                 struct request *req = NULL;
54
55                 spin_lock_irq(q->queue_lock);
56                 set_current_state(TASK_INTERRUPTIBLE);
57                 if (!blk_queue_plugged(q))
58                         req = elv_next_request(q);
59                 mq->req = req;
60                 spin_unlock_irq(q->queue_lock);
61
62                 if (!req) {
63                         if (kthread_should_stop()) {
64                                 set_current_state(TASK_RUNNING);
65                                 break;
66                         }
67                         up(&mq->thread_sem);
68                         schedule();
69                         down(&mq->thread_sem);
70                         continue;
71                 }
72                 set_current_state(TASK_RUNNING);
73
74                 mq->issue_fn(mq, req);
75         } while (1);
76         up(&mq->thread_sem);
77
78         return 0;
79 }
80
81 /*
82  * Generic MMC request handler.  This is called for any queue on a
83  * particular host.  When the host is not busy, we look for a request
84  * on any queue on this host, and attempt to issue it.  This may
85  * not be the queue we were asked to process.
86  */
87 static void mmc_request(struct request_queue *q)
88 {
89         struct mmc_queue *mq = q->queuedata;
90         struct request *req;
91         int ret;
92
93         if (!mq) {
94                 printk(KERN_ERR "MMC: killing requests for dead queue\n");
95                 while ((req = elv_next_request(q)) != NULL) {
96                         do {
97                                 ret = __blk_end_request(req, -EIO,
98                                                         blk_rq_cur_bytes(req));
99                         } while (ret);
100                 }
101                 return;
102         }
103
104         if (!mq->req)
105                 wake_up_process(mq->thread);
106 }
107
108 /**
109  * mmc_init_queue - initialise a queue structure.
110  * @mq: mmc queue
111  * @card: mmc card to attach this queue
112  * @lock: queue lock
113  *
114  * Initialise a MMC card request queue.
115  */
116 int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock)
117 {
118         struct mmc_host *host = card->host;
119         u64 limit = BLK_BOUNCE_HIGH;
120         int ret;
121
122         if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask)
123                 limit = *mmc_dev(host)->dma_mask;
124
125         mq->card = card;
126         mq->queue = blk_init_queue(mmc_request, lock);
127         if (!mq->queue)
128                 return -ENOMEM;
129
130         mq->queue->queuedata = mq;
131         mq->req = NULL;
132
133         blk_queue_prep_rq(mq->queue, mmc_prep_request);
134         blk_queue_ordered(mq->queue, QUEUE_ORDERED_DRAIN, NULL);
135         queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
136
137 #ifdef CONFIG_MMC_BLOCK_BOUNCE
138         if (host->max_hw_segs == 1) {
139                 unsigned int bouncesz;
140
141                 bouncesz = MMC_QUEUE_BOUNCESZ;
142
143                 if (bouncesz > host->max_req_size)
144                         bouncesz = host->max_req_size;
145                 if (bouncesz > host->max_seg_size)
146                         bouncesz = host->max_seg_size;
147                 if (bouncesz > (host->max_blk_count * 512))
148                         bouncesz = host->max_blk_count * 512;
149
150                 if (bouncesz > 512) {
151                         mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL);
152                         if (!mq->bounce_buf) {
153                                 printk(KERN_WARNING "%s: unable to "
154                                         "allocate bounce buffer\n",
155                                         mmc_card_name(card));
156                         }
157                 }
158
159                 if (mq->bounce_buf) {
160                         blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY);
161                         blk_queue_max_sectors(mq->queue, bouncesz / 512);
162                         blk_queue_max_phys_segments(mq->queue, bouncesz / 512);
163                         blk_queue_max_hw_segments(mq->queue, bouncesz / 512);
164                         blk_queue_max_segment_size(mq->queue, bouncesz);
165
166                         mq->sg = kmalloc(sizeof(struct scatterlist),
167                                 GFP_KERNEL);
168                         if (!mq->sg) {
169                                 ret = -ENOMEM;
170                                 goto cleanup_queue;
171                         }
172                         sg_init_table(mq->sg, 1);
173
174                         mq->bounce_sg = kmalloc(sizeof(struct scatterlist) *
175                                 bouncesz / 512, GFP_KERNEL);
176                         if (!mq->bounce_sg) {
177                                 ret = -ENOMEM;
178                                 goto cleanup_queue;
179                         }
180                         sg_init_table(mq->bounce_sg, bouncesz / 512);
181                 }
182         }
183 #endif
184
185         if (!mq->bounce_buf) {
186                 blk_queue_bounce_limit(mq->queue, limit);
187                 blk_queue_max_sectors(mq->queue,
188                         min(host->max_blk_count, host->max_req_size / 512));
189                 blk_queue_max_phys_segments(mq->queue, host->max_phys_segs);
190                 blk_queue_max_hw_segments(mq->queue, host->max_hw_segs);
191                 blk_queue_max_segment_size(mq->queue, host->max_seg_size);
192
193                 mq->sg = kmalloc(sizeof(struct scatterlist) *
194                         host->max_phys_segs, GFP_KERNEL);
195                 if (!mq->sg) {
196                         ret = -ENOMEM;
197                         goto cleanup_queue;
198                 }
199                 sg_init_table(mq->sg, host->max_phys_segs);
200         }
201
202         init_MUTEX(&mq->thread_sem);
203
204         mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd");
205         if (IS_ERR(mq->thread)) {
206                 ret = PTR_ERR(mq->thread);
207                 goto free_bounce_sg;
208         }
209
210         return 0;
211  free_bounce_sg:
212         if (mq->bounce_sg)
213                 kfree(mq->bounce_sg);
214         mq->bounce_sg = NULL;
215  cleanup_queue:
216         if (mq->sg)
217                 kfree(mq->sg);
218         mq->sg = NULL;
219         if (mq->bounce_buf)
220                 kfree(mq->bounce_buf);
221         mq->bounce_buf = NULL;
222         blk_cleanup_queue(mq->queue);
223         return ret;
224 }
225
226 void mmc_cleanup_queue(struct mmc_queue *mq)
227 {
228         struct request_queue *q = mq->queue;
229         unsigned long flags;
230
231         /* Mark that we should start throwing out stragglers */
232         spin_lock_irqsave(q->queue_lock, flags);
233         q->queuedata = NULL;
234         spin_unlock_irqrestore(q->queue_lock, flags);
235
236         /* Make sure the queue isn't suspended, as that will deadlock */
237         mmc_queue_resume(mq);
238
239         /* Then terminate our worker thread */
240         kthread_stop(mq->thread);
241
242         if (mq->bounce_sg)
243                 kfree(mq->bounce_sg);
244         mq->bounce_sg = NULL;
245
246         kfree(mq->sg);
247         mq->sg = NULL;
248
249         if (mq->bounce_buf)
250                 kfree(mq->bounce_buf);
251         mq->bounce_buf = NULL;
252
253         blk_cleanup_queue(mq->queue);
254
255         mq->card = NULL;
256 }
257 EXPORT_SYMBOL(mmc_cleanup_queue);
258
259 /**
260  * mmc_queue_suspend - suspend a MMC request queue
261  * @mq: MMC queue to suspend
262  *
263  * Stop the block request queue, and wait for our thread to
264  * complete any outstanding requests.  This ensures that we
265  * won't suspend while a request is being processed.
266  */
267 void mmc_queue_suspend(struct mmc_queue *mq)
268 {
269         struct request_queue *q = mq->queue;
270         unsigned long flags;
271
272         if (!(mq->flags & MMC_QUEUE_SUSPENDED)) {
273                 mq->flags |= MMC_QUEUE_SUSPENDED;
274
275                 spin_lock_irqsave(q->queue_lock, flags);
276                 blk_stop_queue(q);
277                 spin_unlock_irqrestore(q->queue_lock, flags);
278
279                 down(&mq->thread_sem);
280         }
281 }
282
283 /**
284  * mmc_queue_resume - resume a previously suspended MMC request queue
285  * @mq: MMC queue to resume
286  */
287 void mmc_queue_resume(struct mmc_queue *mq)
288 {
289         struct request_queue *q = mq->queue;
290         unsigned long flags;
291
292         if (mq->flags & MMC_QUEUE_SUSPENDED) {
293                 mq->flags &= ~MMC_QUEUE_SUSPENDED;
294
295                 up(&mq->thread_sem);
296
297                 spin_lock_irqsave(q->queue_lock, flags);
298                 blk_start_queue(q);
299                 spin_unlock_irqrestore(q->queue_lock, flags);
300         }
301 }
302
303 /*
304  * Prepare the sg list(s) to be handed of to the host driver
305  */
306 unsigned int mmc_queue_map_sg(struct mmc_queue *mq)
307 {
308         unsigned int sg_len;
309         size_t buflen;
310         struct scatterlist *sg;
311         int i;
312
313         if (!mq->bounce_buf)
314                 return blk_rq_map_sg(mq->queue, mq->req, mq->sg);
315
316         BUG_ON(!mq->bounce_sg);
317
318         sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg);
319
320         mq->bounce_sg_len = sg_len;
321
322         buflen = 0;
323         for_each_sg(mq->bounce_sg, sg, sg_len, i)
324                 buflen += sg->length;
325
326         sg_init_one(mq->sg, mq->bounce_buf, buflen);
327
328         return 1;
329 }
330
331 /*
332  * If writing, bounce the data to the buffer before the request
333  * is sent to the host driver
334  */
335 void mmc_queue_bounce_pre(struct mmc_queue *mq)
336 {
337         unsigned long flags;
338
339         if (!mq->bounce_buf)
340                 return;
341
342         if (rq_data_dir(mq->req) != WRITE)
343                 return;
344
345         local_irq_save(flags);
346         sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len,
347                 mq->bounce_buf, mq->sg[0].length);
348         local_irq_restore(flags);
349 }
350
351 /*
352  * If reading, bounce the data from the buffer after the request
353  * has been handled by the host driver
354  */
355 void mmc_queue_bounce_post(struct mmc_queue *mq)
356 {
357         unsigned long flags;
358
359         if (!mq->bounce_buf)
360                 return;
361
362         if (rq_data_dir(mq->req) != READ)
363                 return;
364
365         local_irq_save(flags);
366         sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len,
367                 mq->bounce_buf, mq->sg[0].length);
368         local_irq_restore(flags);
369 }
370