2 * Functions related to sysfs handling
4 #include <linux/kernel.h>
5 #include <linux/module.h>
7 #include <linux/blkdev.h>
8 #include <linux/blktrace_api.h>
12 struct queue_sysfs_entry
{
13 struct attribute attr
;
14 ssize_t (*show
)(struct request_queue
*, char *);
15 ssize_t (*store
)(struct request_queue
*, const char *, size_t);
19 queue_var_show(unsigned int var
, char *page
)
21 return sprintf(page
, "%d\n", var
);
25 queue_var_store(unsigned long *var
, const char *page
, size_t count
)
27 char *p
= (char *) page
;
29 *var
= simple_strtoul(p
, &p
, 10);
33 static ssize_t
queue_requests_show(struct request_queue
*q
, char *page
)
35 return queue_var_show(q
->nr_requests
, (page
));
39 queue_requests_store(struct request_queue
*q
, const char *page
, size_t count
)
41 struct request_list
*rl
= &q
->rq
;
43 int ret
= queue_var_store(&nr
, page
, count
);
44 if (nr
< BLKDEV_MIN_RQ
)
47 spin_lock_irq(q
->queue_lock
);
49 blk_queue_congestion_threshold(q
);
51 if (rl
->count
[READ
] >= queue_congestion_on_threshold(q
))
52 blk_set_queue_congested(q
, READ
);
53 else if (rl
->count
[READ
] < queue_congestion_off_threshold(q
))
54 blk_clear_queue_congested(q
, READ
);
56 if (rl
->count
[WRITE
] >= queue_congestion_on_threshold(q
))
57 blk_set_queue_congested(q
, WRITE
);
58 else if (rl
->count
[WRITE
] < queue_congestion_off_threshold(q
))
59 blk_clear_queue_congested(q
, WRITE
);
61 if (rl
->count
[READ
] >= q
->nr_requests
) {
62 blk_set_queue_full(q
, READ
);
63 } else if (rl
->count
[READ
]+1 <= q
->nr_requests
) {
64 blk_clear_queue_full(q
, READ
);
65 wake_up(&rl
->wait
[READ
]);
68 if (rl
->count
[WRITE
] >= q
->nr_requests
) {
69 blk_set_queue_full(q
, WRITE
);
70 } else if (rl
->count
[WRITE
]+1 <= q
->nr_requests
) {
71 blk_clear_queue_full(q
, WRITE
);
72 wake_up(&rl
->wait
[WRITE
]);
74 spin_unlock_irq(q
->queue_lock
);
78 static ssize_t
queue_ra_show(struct request_queue
*q
, char *page
)
80 int ra_kb
= q
->backing_dev_info
.ra_pages
<< (PAGE_CACHE_SHIFT
- 10);
82 return queue_var_show(ra_kb
, (page
));
86 queue_ra_store(struct request_queue
*q
, const char *page
, size_t count
)
89 ssize_t ret
= queue_var_store(&ra_kb
, page
, count
);
91 spin_lock_irq(q
->queue_lock
);
92 q
->backing_dev_info
.ra_pages
= ra_kb
>> (PAGE_CACHE_SHIFT
- 10);
93 spin_unlock_irq(q
->queue_lock
);
98 static ssize_t
queue_max_sectors_show(struct request_queue
*q
, char *page
)
100 int max_sectors_kb
= q
->max_sectors
>> 1;
102 return queue_var_show(max_sectors_kb
, (page
));
106 queue_max_sectors_store(struct request_queue
*q
, const char *page
, size_t count
)
108 unsigned long max_sectors_kb
,
109 max_hw_sectors_kb
= q
->max_hw_sectors
>> 1,
110 page_kb
= 1 << (PAGE_CACHE_SHIFT
- 10);
111 ssize_t ret
= queue_var_store(&max_sectors_kb
, page
, count
);
113 if (max_sectors_kb
> max_hw_sectors_kb
|| max_sectors_kb
< page_kb
)
116 * Take the queue lock to update the readahead and max_sectors
117 * values synchronously:
119 spin_lock_irq(q
->queue_lock
);
120 q
->max_sectors
= max_sectors_kb
<< 1;
121 spin_unlock_irq(q
->queue_lock
);
126 static ssize_t
queue_max_hw_sectors_show(struct request_queue
*q
, char *page
)
128 int max_hw_sectors_kb
= q
->max_hw_sectors
>> 1;
130 return queue_var_show(max_hw_sectors_kb
, (page
));
134 static struct queue_sysfs_entry queue_requests_entry
= {
135 .attr
= {.name
= "nr_requests", .mode
= S_IRUGO
| S_IWUSR
},
136 .show
= queue_requests_show
,
137 .store
= queue_requests_store
,
140 static struct queue_sysfs_entry queue_ra_entry
= {
141 .attr
= {.name
= "read_ahead_kb", .mode
= S_IRUGO
| S_IWUSR
},
142 .show
= queue_ra_show
,
143 .store
= queue_ra_store
,
146 static struct queue_sysfs_entry queue_max_sectors_entry
= {
147 .attr
= {.name
= "max_sectors_kb", .mode
= S_IRUGO
| S_IWUSR
},
148 .show
= queue_max_sectors_show
,
149 .store
= queue_max_sectors_store
,
152 static struct queue_sysfs_entry queue_max_hw_sectors_entry
= {
153 .attr
= {.name
= "max_hw_sectors_kb", .mode
= S_IRUGO
},
154 .show
= queue_max_hw_sectors_show
,
157 static struct queue_sysfs_entry queue_iosched_entry
= {
158 .attr
= {.name
= "scheduler", .mode
= S_IRUGO
| S_IWUSR
},
159 .show
= elv_iosched_show
,
160 .store
= elv_iosched_store
,
163 static struct attribute
*default_attrs
[] = {
164 &queue_requests_entry
.attr
,
165 &queue_ra_entry
.attr
,
166 &queue_max_hw_sectors_entry
.attr
,
167 &queue_max_sectors_entry
.attr
,
168 &queue_iosched_entry
.attr
,
172 #define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
175 queue_attr_show(struct kobject
*kobj
, struct attribute
*attr
, char *page
)
177 struct queue_sysfs_entry
*entry
= to_queue(attr
);
178 struct request_queue
*q
=
179 container_of(kobj
, struct request_queue
, kobj
);
184 mutex_lock(&q
->sysfs_lock
);
185 if (test_bit(QUEUE_FLAG_DEAD
, &q
->queue_flags
)) {
186 mutex_unlock(&q
->sysfs_lock
);
189 res
= entry
->show(q
, page
);
190 mutex_unlock(&q
->sysfs_lock
);
195 queue_attr_store(struct kobject
*kobj
, struct attribute
*attr
,
196 const char *page
, size_t length
)
198 struct queue_sysfs_entry
*entry
= to_queue(attr
);
199 struct request_queue
*q
= container_of(kobj
, struct request_queue
, kobj
);
205 mutex_lock(&q
->sysfs_lock
);
206 if (test_bit(QUEUE_FLAG_DEAD
, &q
->queue_flags
)) {
207 mutex_unlock(&q
->sysfs_lock
);
210 res
= entry
->store(q
, page
, length
);
211 mutex_unlock(&q
->sysfs_lock
);
216 * blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
217 * @kobj: the kobj belonging of the request queue to be released
220 * blk_cleanup_queue is the pair to blk_init_queue() or
221 * blk_queue_make_request(). It should be called when a request queue is
222 * being released; typically when a block device is being de-registered.
223 * Currently, its primary task it to free all the &struct request
224 * structures that were allocated to the queue and the queue itself.
227 * Hopefully the low level driver will have finished any
228 * outstanding requests first...
230 static void blk_release_queue(struct kobject
*kobj
)
232 struct request_queue
*q
=
233 container_of(kobj
, struct request_queue
, kobj
);
234 struct request_list
*rl
= &q
->rq
;
239 mempool_destroy(rl
->rq_pool
);
242 __blk_queue_free_tags(q
);
244 blk_trace_shutdown(q
);
246 bdi_destroy(&q
->backing_dev_info
);
247 kmem_cache_free(blk_requestq_cachep
, q
);
250 static struct sysfs_ops queue_sysfs_ops
= {
251 .show
= queue_attr_show
,
252 .store
= queue_attr_store
,
255 struct kobj_type blk_queue_ktype
= {
256 .sysfs_ops
= &queue_sysfs_ops
,
257 .default_attrs
= default_attrs
,
258 .release
= blk_release_queue
,
261 int blk_register_queue(struct gendisk
*disk
)
265 struct request_queue
*q
= disk
->queue
;
267 if (!q
|| !q
->request_fn
)
270 ret
= kobject_add(&q
->kobj
, kobject_get(&disk
->dev
.kobj
),
275 kobject_uevent(&q
->kobj
, KOBJ_ADD
);
277 ret
= elv_register_queue(q
);
279 kobject_uevent(&q
->kobj
, KOBJ_REMOVE
);
280 kobject_del(&q
->kobj
);
287 void blk_unregister_queue(struct gendisk
*disk
)
289 struct request_queue
*q
= disk
->queue
;
291 if (q
&& q
->request_fn
) {
292 elv_unregister_queue(q
);
294 kobject_uevent(&q
->kobj
, KOBJ_REMOVE
);
295 kobject_del(&q
->kobj
);
296 kobject_put(&disk
->dev
.kobj
);