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dm delay: refactor repetitive code 

dm-delay has a lot of code that is repeated for delaying read and write
bios.  Repetitive code is generally bad; refactor out the repetitive
code in preperation for adding another delay class for flush bios.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka 2018-04-17 00:33:13 +02:00 committed by Mike Snitzer
parent af9313c32c
commit 3876ac76f0
1 changed files with 110 additions and 127 deletions
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237
drivers/md/dm-delay.c
View File

@ -17,6 +17,13 @@
#define DM_MSG_PREFIX "delay" #define DM_MSG_PREFIX "delay"
struct delay_class {
struct dm_dev *dev;
sector_t start;
unsigned delay;
unsigned ops;
};
struct delay_c { struct delay_c {
struct timer_list delay_timer; struct timer_list delay_timer;
struct mutex timer_lock; struct mutex timer_lock;
@ -25,19 +32,15 @@ struct delay_c {
struct list_head delayed_bios; struct list_head delayed_bios;
atomic_t may_delay; atomic_t may_delay;
struct dm_dev *dev_read; struct delay_class read;
sector_t start_read; struct delay_class write;
unsigned read_delay;
unsigned reads;
struct dm_dev *dev_write; int argc;
sector_t start_write;
unsigned write_delay;
unsigned writes;
}; };
struct dm_delay_info { struct dm_delay_info {
struct delay_c *context; struct delay_c *context;
struct delay_class *class;
struct list_head list; struct list_head list;
unsigned long expires; unsigned long expires;
}; };
@ -77,7 +80,7 @@ static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
{ {
struct dm_delay_info *delayed, *next; struct dm_delay_info *delayed, *next;
unsigned long next_expires = 0; unsigned long next_expires = 0;
int start_timer = 0; unsigned long start_timer = 0;
struct bio_list flush_bios = { }; struct bio_list flush_bios = { };
mutex_lock(&delayed_bios_lock); mutex_lock(&delayed_bios_lock);
@ -87,10 +90,7 @@ static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
sizeof(struct dm_delay_info)); sizeof(struct dm_delay_info));
list_del(&delayed->list); list_del(&delayed->list);
bio_list_add(&flush_bios, bio); bio_list_add(&flush_bios, bio);
if ((bio_data_dir(bio) == WRITE)) delayed->class->ops--;
delayed->context->writes--;
else
delayed->context->reads--;
continue; continue;
} }
@ -100,7 +100,6 @@ static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
} else } else
next_expires = min(next_expires, delayed->expires); next_expires = min(next_expires, delayed->expires);
} }
mutex_unlock(&delayed_bios_lock); mutex_unlock(&delayed_bios_lock);
if (start_timer) if (start_timer)
@ -117,6 +116,48 @@ static void flush_expired_bios(struct work_struct *work)
flush_bios(flush_delayed_bios(dc, 0)); flush_bios(flush_delayed_bios(dc, 0));
} }
static void delay_dtr(struct dm_target *ti)
{
struct delay_c *dc = ti->private;
destroy_workqueue(dc->kdelayd_wq);
if (dc->read.dev)
dm_put_device(ti, dc->read.dev);
if (dc->write.dev)
dm_put_device(ti, dc->write.dev);
mutex_destroy(&dc->timer_lock);
kfree(dc);
}
static int delay_class_ctr(struct dm_target *ti, struct delay_class *c, char **argv)
{
int ret;
unsigned long long tmpll;
char dummy;
if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
ti->error = "Invalid device sector";
return -EINVAL;
}
c->start = tmpll;
if (sscanf(argv[2], "%u%c", &c->delay, &dummy) != 1) {
ti->error = "Invalid delay";
return -EINVAL;
}
ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &c->dev);
if (ret) {
ti->error = "Device lookup failed";
return ret;
}
return 0;
}
/* /*
* Mapping parameters: * Mapping parameters:
* <device> <offset> <delay> [<write_device> <write_offset> <write_delay>] * <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
@ -128,8 +169,6 @@ static void flush_expired_bios(struct work_struct *work)
static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv) static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{ {
struct delay_c *dc; struct delay_c *dc;
unsigned long long tmpll;
char dummy;
int ret; int ret;
if (argc != 3 && argc != 6) { if (argc != 3 && argc != 6) {
@ -137,125 +176,69 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
return -EINVAL; return -EINVAL;
} }
dc = kmalloc(sizeof(*dc), GFP_KERNEL); dc = kzalloc(sizeof(*dc), GFP_KERNEL);
if (!dc) { if (!dc) {
ti->error = "Cannot allocate context"; ti->error = "Cannot allocate context";
return -ENOMEM; return -ENOMEM;
} }
dc->reads = dc->writes = 0; ti->private = dc;
ret = -EINVAL;
if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
ti->error = "Invalid device sector";
goto bad;
}
dc->start_read = tmpll;
if (sscanf(argv[2], "%u%c", &dc->read_delay, &dummy) != 1) {
ti->error = "Invalid delay";
goto bad;
}
ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
&dc->dev_read);
if (ret) {
ti->error = "Device lookup failed";
goto bad;
}
ret = -EINVAL;
dc->dev_write = NULL;
if (argc == 3)
goto out;
if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
ti->error = "Invalid write device sector";
goto bad_dev_read;
}
dc->start_write = tmpll;
if (sscanf(argv[5], "%u%c", &dc->write_delay, &dummy) != 1) {
ti->error = "Invalid write delay";
goto bad_dev_read;
}
ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table),
&dc->dev_write);
if (ret) {
ti->error = "Write device lookup failed";
goto bad_dev_read;
}
out:
ret = -EINVAL;
dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
if (!dc->kdelayd_wq) {
DMERR("Couldn't start kdelayd");
goto bad_queue;
}
timer_setup(&dc->delay_timer, handle_delayed_timer, 0); timer_setup(&dc->delay_timer, handle_delayed_timer, 0);
INIT_WORK(&dc->flush_expired_bios, flush_expired_bios); INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
INIT_LIST_HEAD(&dc->delayed_bios); INIT_LIST_HEAD(&dc->delayed_bios);
mutex_init(&dc->timer_lock); mutex_init(&dc->timer_lock);
atomic_set(&dc->may_delay, 1); atomic_set(&dc->may_delay, 1);
dc->argc = argc;
ret = delay_class_ctr(ti, &dc->read, argv);
if (ret)
goto bad;
if (argc == 3) {
ret = delay_class_ctr(ti, &dc->write, argv);
if (ret)
goto bad;
goto out;
}
ret = delay_class_ctr(ti, &dc->write, argv + 3);
if (ret)
goto bad;
out:
dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
if (!dc->kdelayd_wq) {
ret = -EINVAL;
DMERR("Couldn't start kdelayd");
goto bad;
}
ti->num_flush_bios = 1; ti->num_flush_bios = 1;
ti->num_discard_bios = 1; ti->num_discard_bios = 1;
ti->per_io_data_size = sizeof(struct dm_delay_info); ti->per_io_data_size = sizeof(struct dm_delay_info);
ti->private = dc;
return 0; return 0;
bad_queue:
if (dc->dev_write)
dm_put_device(ti, dc->dev_write);
bad_dev_read:
dm_put_device(ti, dc->dev_read);
bad: bad:
kfree(dc); delay_dtr(ti);
return ret; return ret;
} }
static void delay_dtr(struct dm_target *ti) static int delay_bio(struct delay_c *dc, struct delay_class *c, struct bio *bio)
{
struct delay_c *dc = ti->private;
destroy_workqueue(dc->kdelayd_wq);
dm_put_device(ti, dc->dev_read);
if (dc->dev_write)
dm_put_device(ti, dc->dev_write);
mutex_destroy(&dc->timer_lock);
kfree(dc);
}
static int delay_bio(struct delay_c *dc, int delay, struct bio *bio)
{ {
struct dm_delay_info *delayed; struct dm_delay_info *delayed;
unsigned long expires = 0; unsigned long expires = 0;
if (!delay || !atomic_read(&dc->may_delay)) if (!c->delay || !atomic_read(&dc->may_delay))
return DM_MAPIO_REMAPPED; return DM_MAPIO_REMAPPED;
delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info)); delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
delayed->context = dc; delayed->context = dc;
delayed->expires = expires = jiffies + msecs_to_jiffies(delay); delayed->expires = expires = jiffies + msecs_to_jiffies(c->delay);
mutex_lock(&delayed_bios_lock); mutex_lock(&delayed_bios_lock);
c->ops++;
if (bio_data_dir(bio) == WRITE)
dc->writes++;
else
dc->reads++;
list_add_tail(&delayed->list, &dc->delayed_bios); list_add_tail(&delayed->list, &dc->delayed_bios);
mutex_unlock(&delayed_bios_lock); mutex_unlock(&delayed_bios_lock);
queue_timeout(dc, expires); queue_timeout(dc, expires);
@ -282,23 +265,25 @@ static void delay_resume(struct dm_target *ti)
static int delay_map(struct dm_target *ti, struct bio *bio) static int delay_map(struct dm_target *ti, struct bio *bio)
{ {
struct delay_c *dc = ti->private; struct delay_c *dc = ti->private;
struct delay_class *c;
struct dm_delay_info *delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
if ((bio_data_dir(bio) == WRITE) && (dc->dev_write)) { if (bio_data_dir(bio) == WRITE) {
bio_set_dev(bio, dc->dev_write->bdev); c = &dc->write;
if (bio_sectors(bio)) } else {
bio->bi_iter.bi_sector = dc->start_write + c = &dc->read;
dm_target_offset(ti, bio->bi_iter.bi_sector);
return delay_bio(dc, dc->write_delay, bio);
} }
delayed->class = c;
bio_set_dev(bio, c->dev->bdev);
if (bio_sectors(bio))
bio->bi_iter.bi_sector = c->start + dm_target_offset(ti, bio->bi_iter.bi_sector);
bio_set_dev(bio, dc->dev_read->bdev); return delay_bio(dc, c, bio);
bio->bi_iter.bi_sector = dc->start_read +
dm_target_offset(ti, bio->bi_iter.bi_sector);
return delay_bio(dc, dc->read_delay, bio);
} }
#define DMEMIT_DELAY_CLASS(c) \
DMEMIT("%s %llu %u", (c)->dev->name, (unsigned long long)(c)->start, (c)->delay)
static void delay_status(struct dm_target *ti, status_type_t type, static void delay_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen) unsigned status_flags, char *result, unsigned maxlen)
{ {
@ -307,17 +292,15 @@ static void delay_status(struct dm_target *ti, status_type_t type,
switch (type) { switch (type) {
case STATUSTYPE_INFO: case STATUSTYPE_INFO:
DMEMIT("%u %u", dc->reads, dc->writes); DMEMIT("%u %u", dc->read.ops, dc->write.ops);
break; break;
case STATUSTYPE_TABLE: case STATUSTYPE_TABLE:
DMEMIT("%s %llu %u", dc->dev_read->name, DMEMIT_DELAY_CLASS(&dc->read);
(unsigned long long) dc->start_read, if (dc->argc >= 6) {
dc->read_delay); DMEMIT(" ");
if (dc->dev_write) DMEMIT_DELAY_CLASS(&dc->write);
DMEMIT(" %s %llu %u", dc->dev_write->name, }
(unsigned long long) dc->start_write,
dc->write_delay);
break; break;
} }
} }
@ -328,12 +311,12 @@ static int delay_iterate_devices(struct dm_target *ti,
struct delay_c *dc = ti->private; struct delay_c *dc = ti->private;
int ret = 0; int ret = 0;
ret = fn(ti, dc->dev_read, dc->start_read, ti->len, data); ret = fn(ti, dc->read.dev, dc->read.start, ti->len, data);
if (ret)
goto out;
ret = fn(ti, dc->write.dev, dc->write.start, ti->len, data);
if (ret) if (ret)
goto out; goto out;
if (dc->dev_write)
ret = fn(ti, dc->dev_write, dc->start_write, ti->len, data);
out: out:
return ret; return ret;