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/*
* Functions related to sysfs handling
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/blktrace_api.h>

#include "blk.h"

struct queue_sysfs_entry {
struct attribute attr;
ssize_t (*show)(struct request_queue *, char *);
ssize_t (*store)(struct request_queue *, const char *, size_t);
};

static ssize_t
queue_var_show(unsigned long var, char *page)
{
return sprintf(page, "%lu\n", var);
}

static ssize_t
queue_var_store(unsigned long *var, const char *page, size_t count)
{
char *p = (char *) page;

*var = simple_strtoul(p, &p, 10);
return count;
}

static ssize_t queue_requests_show(struct request_queue *q, char *page)
{
return queue_var_show(q->nr_requests, (page));
}

static ssize_t
queue_requests_store(struct request_queue *q, const char *page, size_t count)
{
struct request_list *rl = &q->rq;
unsigned long nr;
int ret;

if (!q->request_fn)
return -EINVAL;

ret = queue_var_store(&nr, page, count);
if (nr < BLKDEV_MIN_RQ)
nr = BLKDEV_MIN_RQ;

spin_lock_irq(q->queue_lock);
q->nr_requests = nr;
blk_queue_congestion_threshold(q);

if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
blk_set_queue_congested(q, BLK_RW_SYNC);
else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
blk_clear_queue_congested(q, BLK_RW_SYNC);

if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q))
blk_set_queue_congested(q, BLK_RW_ASYNC);
else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
blk_clear_queue_congested(q, BLK_RW_ASYNC);

if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
blk_set_queue_full(q, BLK_RW_SYNC);
} else if (rl->count[BLK_RW_SYNC]+1 <= q->nr_requests) {
blk_clear_queue_full(q, BLK_RW_SYNC);
wake_up(&rl->wait[BLK_RW_SYNC]);
}

if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
blk_set_queue_full(q, BLK_RW_ASYNC);
} else if (rl->count[BLK_RW_ASYNC]+1 <= q->nr_requests) {
blk_clear_queue_full(q, BLK_RW_ASYNC);
wake_up(&rl->wait[BLK_RW_ASYNC]);
}
spin_unlock_irq(q->queue_lock);
return ret;
}

static ssize_t queue_ra_show(struct request_queue *q, char *page)
{
unsigned long ra_kb = q->backing_dev_info.ra_pages <<
(PAGE_CACHE_SHIFT - 10);

return queue_var_show(ra_kb, (page));
}

static ssize_t
queue_ra_store(struct request_queue *q, const char *page, size_t count)
{
unsigned long ra_kb;
ssize_t ret = queue_var_store(&ra_kb, page, count);

q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);

return ret;
}

static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
{
int max_sectors_kb = queue_max_sectors(q) >> 1;

return queue_var_show(max_sectors_kb, (page));
}

static ssize_t queue_max_segments_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_max_segments(q), (page));
}

static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
{
return queue_var_show(q->limits.max_integrity_segments, (page));
}

static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
{
if (blk_queue_cluster(q))
return queue_var_show(queue_max_segment_size(q), (page));

return queue_var_show(PAGE_CACHE_SIZE, (page));
}

static ssize_t queue_logical_block_size_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_logical_block_size(q), page);
}

static ssize_t queue_physical_block_size_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_physical_block_size(q), page);
}

static ssize_t queue_io_min_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_io_min(q), page);
}

static ssize_t queue_io_opt_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_io_opt(q), page);
}

static ssize_t queue_discard_granularity_show(struct request_queue *q, char *page)
{
return queue_var_show(q->limits.discard_granularity, page);
}

static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
{
return queue_var_show(q->limits.max_discard_sectors << 9, page);
}

static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
{
return queue_var_show(queue_discard_zeroes_data(q), page);
}

static ssize_t
queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
{
unsigned long max_sectors_kb,
max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
ssize_t ret = queue_var_store(&max_sectors_kb, page, count);

if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
return -EINVAL;

spin_lock_irq(q->queue_lock);
q->limits.max_sectors = max_sectors_kb << 1;
spin_unlock_irq(q->queue_lock);

return ret;
}

static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
{
int max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1;

return queue_var_show(max_hw_sectors_kb, (page));
}

#define QUEUE_SYSFS_BIT_FNS(name, flag, neg) \
static ssize_t \
queue_show_##name(struct request_queue *q, char *page) \
{ \
int bit; \
bit = test_bit(QUEUE_FLAG_##flag, &q->queue_flags); \
return queue_var_show(neg ? !bit : bit, page); \
} \
static ssize_t \
queue_store_##name(struct request_queue *q, const char *page, size_t count) \
{ \
unsigned long val; \
ssize_t ret; \
ret = queue_var_store(&val, page, count); \
if (neg) \
val = !val; \
\
spin_lock_irq(q->queue_lock); \
if (val) \
queue_flag_set(QUEUE_FLAG_##flag, q); \
else \
queue_flag_clear(QUEUE_FLAG_##flag, q); \
spin_unlock_irq(q->queue_lock); \
return ret; \
}

QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1);
QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
#undef QUEUE_SYSFS_BIT_FNS

static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
{
return queue_var_show((blk_queue_nomerges(q) << 1) |
blk_queue_noxmerges(q), page);
}

static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
size_t count)
{
unsigned long nm;
ssize_t ret = queue_var_store(&nm, page, count);

spin_lock_irq(q->queue_lock);
queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
if (nm == 2)
queue_flag_set(QUEUE_FLAG_NOMERGES, q);
else if (nm)
queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
spin_unlock_irq(q->queue_lock);

return ret;
}

static ssize_t queue_rq_affinity_show(struct request_queue *q, char *page)
{
bool set = test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags);

return queue_var_show(set, page);
}

static ssize_t
queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
{
ssize_t ret = -EINVAL;
#if defined(CONFIG_USE_GENERIC_SMP_HELPERS)
unsigned long val;

ret = queue_var_store(&val, page, count);
spin_lock_irq(q->queue_lock);
if (val)
queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
else
queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
spin_unlock_irq(q->queue_lock);
#endif
return ret;
}

static struct queue_sysfs_entry queue_requests_entry = {
.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
.show = queue_requests_show,
.store = queue_requests_store,
};

static struct queue_sysfs_entry queue_ra_entry = {
.attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
.show = queue_ra_show,
.store = queue_ra_store,
};

static struct queue_sysfs_entry queue_max_sectors_entry = {
.attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
.show = queue_max_sectors_show,
.store = queue_max_sectors_store,
};

static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
.attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
.show = queue_max_hw_sectors_show,
};

static struct queue_sysfs_entry queue_max_segments_entry = {
.attr = {.name = "max_segments", .mode = S_IRUGO },
.show = queue_max_segments_show,
};

static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
.attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
.show = queue_max_integrity_segments_show,
};

static struct queue_sysfs_entry queue_max_segment_size_entry = {
.attr = {.name = "max_segment_size", .mode = S_IRUGO },
.show = queue_max_segment_size_show,
};

static struct queue_sysfs_entry queue_iosched_entry = {
.attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
.show = elv_iosched_show,
.store = elv_iosched_store,
};

static struct queue_sysfs_entry queue_hw_sector_size_entry = {
.attr = {.name = "hw_sector_size", .mode = S_IRUGO },
.show = queue_logical_block_size_show,
};

static struct queue_sysfs_entry queue_logical_block_size_entry = {
.attr = {.name = "logical_block_size", .mode = S_IRUGO },
.show = queue_logical_block_size_show,
};

static struct queue_sysfs_entry queue_physical_block_size_entry = {
.attr = {.name = "physical_block_size", .mode = S_IRUGO },
.show = queue_physical_block_size_show,
};

static struct queue_sysfs_entry queue_io_min_entry = {
.attr = {.name = "minimum_io_size", .mode = S_IRUGO },
.show = queue_io_min_show,
};

static struct queue_sysfs_entry queue_io_opt_entry = {
.attr = {.name = "optimal_io_size", .mode = S_IRUGO },
.show = queue_io_opt_show,
};

static struct queue_sysfs_entry queue_discard_granularity_entry = {
.attr = {.name = "discard_granularity", .mode = S_IRUGO },
.show = queue_discard_granularity_show,
};

static struct queue_sysfs_entry queue_discard_max_entry = {
.attr = {.name = "discard_max_bytes", .mode = S_IRUGO },
.show = queue_discard_max_show,
};

static struct queue_sysfs_entry queue_discard_zeroes_data_entry = {
.attr = {.name = "discard_zeroes_data", .mode = S_IRUGO },
.show = queue_discard_zeroes_data_show,
};

static struct queue_sysfs_entry queue_nonrot_entry = {
.attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
.show = queue_show_nonrot,
.store = queue_store_nonrot,
};

static struct queue_sysfs_entry queue_nomerges_entry = {
.attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
.show = queue_nomerges_show,
.store = queue_nomerges_store,
};

static struct queue_sysfs_entry queue_rq_affinity_entry = {
.attr = {.name = "rq_affinity", .mode = S_IRUGO | S_IWUSR },
.show = queue_rq_affinity_show,
.store = queue_rq_affinity_store,
};

static struct queue_sysfs_entry queue_iostats_entry = {
.attr = {.name = "iostats", .mode = S_IRUGO | S_IWUSR },
.show = queue_show_iostats,
.store = queue_store_iostats,
};

static struct queue_sysfs_entry queue_random_entry = {
.attr = {.name = "add_random", .mode = S_IRUGO | S_IWUSR },
.show = queue_show_random,
.store = queue_store_random,
};

static struct attribute *default_attrs[] = {
&queue_requests_entry.attr,
&queue_ra_entry.attr,
&queue_max_hw_sectors_entry.attr,
&queue_max_sectors_entry.attr,
&queue_max_segments_entry.attr,
&queue_max_integrity_segments_entry.attr,
&queue_max_segment_size_entry.attr,
&queue_iosched_entry.attr,
&queue_hw_sector_size_entry.attr,
&queue_logical_block_size_entry.attr,
&queue_physical_block_size_entry.attr,
&queue_io_min_entry.attr,
&queue_io_opt_entry.attr,
&queue_discard_granularity_entry.attr,
&queue_discard_max_entry.attr,
&queue_discard_zeroes_data_entry.attr,
&queue_nonrot_entry.attr,
&queue_nomerges_entry.attr,
&queue_rq_affinity_entry.attr,
&queue_iostats_entry.attr,
&queue_random_entry.attr,
NULL,
};

#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)

static ssize_t
queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
{
struct queue_sysfs_entry *entry = to_queue(attr);
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
ssize_t res;

if (!entry->show)
return -EIO;
mutex_lock(&q->sysfs_lock);
if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
mutex_unlock(&q->sysfs_lock);
return -ENOENT;
}
res = entry->show(q, page);
mutex_unlock(&q->sysfs_lock);
return res;
}

static ssize_t
queue_attr_store(struct kobject *kobj, struct attribute *attr,
const char *page, size_t length)
{
struct queue_sysfs_entry *entry = to_queue(attr);
struct request_queue *q;
ssize_t res;

if (!entry->store)
return -EIO;

q = container_of(kobj, struct request_queue, kobj);
mutex_lock(&q->sysfs_lock);
if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
mutex_unlock(&q->sysfs_lock);
return -ENOENT;
}
res = entry->store(q, page, length);
mutex_unlock(&q->sysfs_lock);
return res;
}

/**
* blk_cleanup_queue: - release a &struct request_queue when it is no longer needed
* @kobj: the kobj belonging of the request queue to be released
*
* Description:
* blk_cleanup_queue is the pair to blk_init_queue() or
* blk_queue_make_request(). It should be called when a request queue is
* being released; typically when a block device is being de-registered.
* Currently, its primary task it to free all the &struct request
* structures that were allocated to the queue and the queue itself.
*
* Caveat:
* Hopefully the low level driver will have finished any
* outstanding requests first...
**/
static void blk_release_queue(struct kobject *kobj)
{
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
struct request_list *rl = &q->rq;

blk_sync_queue(q);

blk_throtl_exit(q);

if (rl->rq_pool)
mempool_destroy(rl->rq_pool);

if (q->queue_tags)
__blk_queue_free_tags(q);

blk_trace_shutdown(q);

bdi_destroy(&q->backing_dev_info);
kmem_cache_free(blk_requestq_cachep, q);
}

static const struct sysfs_ops queue_sysfs_ops = {
.show = queue_attr_show,
.store = queue_attr_store,
};

struct kobj_type blk_queue_ktype = {
.sysfs_ops = &queue_sysfs_ops,
.default_attrs = default_attrs,
.release = blk_release_queue,
};

int blk_register_queue(struct gendisk *disk)
{
int ret;
struct device *dev = disk_to_dev(disk);

struct request_queue *q = disk->queue;

if (WARN_ON(!q))
return -ENXIO;

ret = blk_trace_init_sysfs(dev);
if (ret)
return ret;

ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue");
if (ret < 0)
return ret;

kobject_uevent(&q->kobj, KOBJ_ADD);

if (!q->request_fn)
return 0;

ret = elv_register_queue(q);
if (ret) {
kobject_uevent(&q->kobj, KOBJ_REMOVE);
kobject_del(&q->kobj);
blk_trace_remove_sysfs(disk_to_dev(disk));
kobject_put(&dev->kobj);
return ret;
}

return 0;
}

void blk_unregister_queue(struct gendisk *disk)
{
struct request_queue *q = disk->queue;

if (WARN_ON(!q))
return;

if (q->request_fn)
elv_unregister_queue(q);

kobject_uevent(&q->kobj, KOBJ_REMOVE);
kobject_del(&q->kobj);
blk_trace_remove_sysfs(disk_to_dev(disk));
kobject_put(&disk_to_dev(disk)->kobj);
}
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