dm-delay has a lot of code that is repeated for delaying read and write
bios. Repetitive code is generally bad; I intend to add another class for
flush bios, so I refactor out the repetitive code, so that the new class
can be added easily.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/md/dm-delay.c | 226 +++++++++++++++++++++++---------------------------
1 file changed, 104 insertions(+), 122 deletions(-)
Index: linux-2.6/drivers/md/dm-delay.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-delay.c 2018-04-16 21:21:12.000000000 +0200
+++ linux-2.6/drivers/md/dm-delay.c 2018-04-17 00:13:17.000000000 +0200
@@ -17,6 +17,13 @@
#define DM_MSG_PREFIX "delay"
+struct delay_class {
+ struct dm_dev *dev;
+ sector_t start;
+ unsigned delay;
+ unsigned ops;
+};
+
struct delay_c {
struct timer_list delay_timer;
struct mutex timer_lock;
@@ -25,19 +32,15 @@ struct delay_c {
struct list_head delayed_bios;
atomic_t may_delay;
- struct dm_dev *dev_read;
- sector_t start_read;
- unsigned read_delay;
- unsigned reads;
-
- struct dm_dev *dev_write;
- sector_t start_write;
- unsigned write_delay;
- unsigned writes;
+ struct delay_class read;
+ struct delay_class write;
+
+ int argc;
};
struct dm_delay_info {
struct delay_c *context;
+ struct delay_class *class;
struct list_head list;
unsigned long expires;
};
@@ -77,7 +80,7 @@ static struct bio *flush_delayed_bios(st
{
struct dm_delay_info *delayed, *next;
unsigned long next_expires = 0;
- int start_timer = 0;
+ unsigned long start_timer = 0;
struct bio_list flush_bios = { };
mutex_lock(&delayed_bios_lock);
@@ -87,10 +90,7 @@ static struct bio *flush_delayed_bios(st
sizeof(struct dm_delay_info));
list_del(&delayed->list);
bio_list_add(&flush_bios, bio);
- if ((bio_data_dir(bio) == WRITE))
- delayed->context->writes--;
- else
- delayed->context->reads--;
+ delayed->class->ops--;
continue;
}
@@ -100,7 +100,6 @@ static struct bio *flush_delayed_bios(st
} else
next_expires = min(next_expires, delayed->expires);
}
-
mutex_unlock(&delayed_bios_lock);
if (start_timer)
@@ -117,6 +116,48 @@ static void flush_expired_bios(struct wo
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:
* <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
@@ -128,8 +169,6 @@ static void flush_expired_bios(struct wo
static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct delay_c *dc;
- unsigned long long tmpll;
- char dummy;
int ret;
if (argc != 3 && argc != 6) {
@@ -137,125 +176,69 @@ static int delay_ctr(struct dm_target *t
return -EINVAL;
}
- dc = kmalloc(sizeof(*dc), GFP_KERNEL);
+ dc = kzalloc(sizeof(*dc), GFP_KERNEL);
if (!dc) {
ti->error = "Cannot allocate context";
return -ENOMEM;
}
- dc->reads = dc->writes = 0;
-
- 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;
- }
+ ti->private = dc;
+ timer_setup(&dc->delay_timer, handle_delayed_timer, 0);
+ INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
+ INIT_LIST_HEAD(&dc->delayed_bios);
+ mutex_init(&dc->timer_lock);
+ atomic_set(&dc->may_delay, 1);
+ dc->argc = argc;
- ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
- &dc->dev_read);
- if (ret) {
- ti->error = "Device lookup failed";
+ ret = delay_class_ctr(ti, &dc->read, argv);
+ if (ret)
goto bad;
- }
- ret = -EINVAL;
- dc->dev_write = NULL;
- if (argc == 3)
+ if (argc == 3) {
+ ret = delay_class_ctr(ti, &dc->write, argv);
+ if (ret)
+ goto bad;
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;
- }
+ ret = delay_class_ctr(ti, &dc->write, argv + 3);
+ if (ret)
+ goto bad;
out:
- ret = -EINVAL;
dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
if (!dc->kdelayd_wq) {
+ ret = -EINVAL;
DMERR("Couldn't start kdelayd");
- goto bad_queue;
+ goto bad;
}
- timer_setup(&dc->delay_timer, handle_delayed_timer, 0);
-
- INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
- INIT_LIST_HEAD(&dc->delayed_bios);
- mutex_init(&dc->timer_lock);
- atomic_set(&dc->may_delay, 1);
-
ti->num_flush_bios = 1;
ti->num_discard_bios = 1;
ti->per_io_data_size = sizeof(struct dm_delay_info);
- ti->private = dc;
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:
- kfree(dc);
+ delay_dtr(ti);
return ret;
}
-static void delay_dtr(struct dm_target *ti)
-{
- 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)
+static int delay_bio(struct delay_c *dc, struct delay_class *c, struct bio *bio)
{
struct dm_delay_info *delayed;
unsigned long expires = 0;
- if (!delay || !atomic_read(&dc->may_delay))
+ if (!c->delay || !atomic_read(&dc->may_delay))
return DM_MAPIO_REMAPPED;
delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
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);
-
- if (bio_data_dir(bio) == WRITE)
- dc->writes++;
- else
- dc->reads++;
-
+ c->ops++;
list_add_tail(&delayed->list, &dc->delayed_bios);
-
mutex_unlock(&delayed_bios_lock);
queue_timeout(dc, expires);
@@ -282,21 +265,20 @@ static void delay_resume(struct dm_targe
static int delay_map(struct dm_target *ti, struct bio *bio)
{
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)) {
- bio_set_dev(bio, dc->dev_write->bdev);
- if (bio_sectors(bio))
- bio->bi_iter.bi_sector = dc->start_write +
- dm_target_offset(ti, bio->bi_iter.bi_sector);
-
- return delay_bio(dc, dc->write_delay, bio);
- }
-
- bio_set_dev(bio, dc->dev_read->bdev);
- bio->bi_iter.bi_sector = dc->start_read +
- dm_target_offset(ti, bio->bi_iter.bi_sector);
+ if (bio_data_dir(bio) == WRITE) {
+ c = &dc->write;
+ } else {
+ c = &dc->read;
+ }
+ 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);
- return delay_bio(dc, dc->read_delay, bio);
+ return delay_bio(dc, c, bio);
}
static void delay_status(struct dm_target *ti, status_type_t type,
@@ -307,17 +289,17 @@ static void delay_status(struct dm_targe
switch (type) {
case STATUSTYPE_INFO:
- DMEMIT("%u %u", dc->reads, dc->writes);
+ DMEMIT("%u %u", dc->read.ops, dc->write.ops);
break;
case STATUSTYPE_TABLE:
- DMEMIT("%s %llu %u", dc->dev_read->name,
- (unsigned long long) dc->start_read,
- dc->read_delay);
- if (dc->dev_write)
- DMEMIT(" %s %llu %u", dc->dev_write->name,
- (unsigned long long) dc->start_write,
- dc->write_delay);
+#define EMIT_CLASS(c) DMEMIT("%s %llu %u", (c)->dev->name, (unsigned long long)(c)->start, (c)->delay)
+ EMIT_CLASS(&dc->read);
+ if (dc->argc >= 6) {
+ DMEMIT(" ");
+ EMIT_CLASS(&dc->write);
+ }
+#undef EMIT_CLASS
break;
}
}
@@ -328,12 +310,12 @@ static int delay_iterate_devices(struct
struct delay_c *dc = ti->private;
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)
goto out;
-
- if (dc->dev_write)
- ret = fn(ti, dc->dev_write, dc->start_write, ti->len, data);
out:
return ret;
--
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