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
Mike Snitzer
parent
af9313c32c
commit
3876ac76f0
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@ -17,6 +17,13 @@
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#define DM_MSG_PREFIX "delay"
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struct delay_class {
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struct dm_dev *dev;
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sector_t start;
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unsigned delay;
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unsigned ops;
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};
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struct delay_c {
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struct timer_list delay_timer;
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struct mutex timer_lock;
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@ -25,19 +32,15 @@ struct delay_c {
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struct list_head delayed_bios;
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atomic_t may_delay;
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struct dm_dev *dev_read;
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sector_t start_read;
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unsigned read_delay;
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unsigned reads;
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struct delay_class read;
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struct delay_class write;
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struct dm_dev *dev_write;
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sector_t start_write;
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unsigned write_delay;
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unsigned writes;
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int argc;
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};
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struct dm_delay_info {
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struct delay_c *context;
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struct delay_class *class;
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struct list_head list;
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unsigned long expires;
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};
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@ -77,7 +80,7 @@ static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
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{
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struct dm_delay_info *delayed, *next;
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unsigned long next_expires = 0;
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int start_timer = 0;
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unsigned long start_timer = 0;
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struct bio_list flush_bios = { };
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mutex_lock(&delayed_bios_lock);
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@ -87,10 +90,7 @@ static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
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sizeof(struct dm_delay_info));
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list_del(&delayed->list);
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bio_list_add(&flush_bios, bio);
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if ((bio_data_dir(bio) == WRITE))
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delayed->context->writes--;
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else
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delayed->context->reads--;
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delayed->class->ops--;
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continue;
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}
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@ -100,7 +100,6 @@ static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
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} else
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next_expires = min(next_expires, delayed->expires);
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}
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mutex_unlock(&delayed_bios_lock);
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if (start_timer)
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@ -117,6 +116,48 @@ static void flush_expired_bios(struct work_struct *work)
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flush_bios(flush_delayed_bios(dc, 0));
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}
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static void delay_dtr(struct dm_target *ti)
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{
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struct delay_c *dc = ti->private;
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destroy_workqueue(dc->kdelayd_wq);
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if (dc->read.dev)
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dm_put_device(ti, dc->read.dev);
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if (dc->write.dev)
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dm_put_device(ti, dc->write.dev);
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mutex_destroy(&dc->timer_lock);
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kfree(dc);
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}
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static int delay_class_ctr(struct dm_target *ti, struct delay_class *c, char **argv)
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{
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int ret;
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unsigned long long tmpll;
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char dummy;
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if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
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ti->error = "Invalid device sector";
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return -EINVAL;
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}
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c->start = tmpll;
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if (sscanf(argv[2], "%u%c", &c->delay, &dummy) != 1) {
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ti->error = "Invalid delay";
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return -EINVAL;
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}
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ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &c->dev);
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if (ret) {
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ti->error = "Device lookup failed";
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return ret;
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}
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return 0;
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}
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/*
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* Mapping parameters:
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* <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
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@ -128,8 +169,6 @@ static void flush_expired_bios(struct work_struct *work)
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static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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{
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struct delay_c *dc;
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unsigned long long tmpll;
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char dummy;
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int ret;
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if (argc != 3 && argc != 6) {
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@ -137,125 +176,69 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
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return -EINVAL;
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}
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dc = kmalloc(sizeof(*dc), GFP_KERNEL);
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dc = kzalloc(sizeof(*dc), GFP_KERNEL);
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if (!dc) {
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ti->error = "Cannot allocate context";
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return -ENOMEM;
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}
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dc->reads = dc->writes = 0;
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ret = -EINVAL;
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if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
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ti->error = "Invalid device sector";
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goto bad;
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}
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dc->start_read = tmpll;
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if (sscanf(argv[2], "%u%c", &dc->read_delay, &dummy) != 1) {
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ti->error = "Invalid delay";
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goto bad;
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}
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ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
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&dc->dev_read);
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if (ret) {
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ti->error = "Device lookup failed";
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goto bad;
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}
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ret = -EINVAL;
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dc->dev_write = NULL;
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if (argc == 3)
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goto out;
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if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
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ti->error = "Invalid write device sector";
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goto bad_dev_read;
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}
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dc->start_write = tmpll;
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if (sscanf(argv[5], "%u%c", &dc->write_delay, &dummy) != 1) {
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ti->error = "Invalid write delay";
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goto bad_dev_read;
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}
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ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table),
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&dc->dev_write);
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if (ret) {
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ti->error = "Write device lookup failed";
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goto bad_dev_read;
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}
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out:
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ret = -EINVAL;
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dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
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if (!dc->kdelayd_wq) {
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DMERR("Couldn't start kdelayd");
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goto bad_queue;
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}
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ti->private = dc;
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timer_setup(&dc->delay_timer, handle_delayed_timer, 0);
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INIT_WORK(&dc->flush_expired_bios, flush_expired_bios);
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INIT_LIST_HEAD(&dc->delayed_bios);
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mutex_init(&dc->timer_lock);
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atomic_set(&dc->may_delay, 1);
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dc->argc = argc;
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ret = delay_class_ctr(ti, &dc->read, argv);
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if (ret)
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goto bad;
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if (argc == 3) {
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ret = delay_class_ctr(ti, &dc->write, argv);
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if (ret)
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goto bad;
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goto out;
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}
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ret = delay_class_ctr(ti, &dc->write, argv + 3);
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if (ret)
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goto bad;
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out:
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dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
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if (!dc->kdelayd_wq) {
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ret = -EINVAL;
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DMERR("Couldn't start kdelayd");
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goto bad;
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}
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ti->num_flush_bios = 1;
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ti->num_discard_bios = 1;
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ti->per_io_data_size = sizeof(struct dm_delay_info);
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ti->private = dc;
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return 0;
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bad_queue:
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if (dc->dev_write)
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dm_put_device(ti, dc->dev_write);
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bad_dev_read:
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dm_put_device(ti, dc->dev_read);
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bad:
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kfree(dc);
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delay_dtr(ti);
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return ret;
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}
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static void delay_dtr(struct dm_target *ti)
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{
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struct delay_c *dc = ti->private;
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destroy_workqueue(dc->kdelayd_wq);
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dm_put_device(ti, dc->dev_read);
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if (dc->dev_write)
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dm_put_device(ti, dc->dev_write);
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mutex_destroy(&dc->timer_lock);
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kfree(dc);
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}
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static int delay_bio(struct delay_c *dc, int delay, struct bio *bio)
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static int delay_bio(struct delay_c *dc, struct delay_class *c, struct bio *bio)
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{
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struct dm_delay_info *delayed;
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unsigned long expires = 0;
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if (!delay || !atomic_read(&dc->may_delay))
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if (!c->delay || !atomic_read(&dc->may_delay))
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return DM_MAPIO_REMAPPED;
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delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
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delayed->context = dc;
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delayed->expires = expires = jiffies + msecs_to_jiffies(delay);
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delayed->expires = expires = jiffies + msecs_to_jiffies(c->delay);
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mutex_lock(&delayed_bios_lock);
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if (bio_data_dir(bio) == WRITE)
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dc->writes++;
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else
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dc->reads++;
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c->ops++;
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list_add_tail(&delayed->list, &dc->delayed_bios);
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mutex_unlock(&delayed_bios_lock);
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queue_timeout(dc, expires);
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@ -282,23 +265,25 @@ static void delay_resume(struct dm_target *ti)
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static int delay_map(struct dm_target *ti, struct bio *bio)
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{
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struct delay_c *dc = ti->private;
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struct delay_class *c;
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struct dm_delay_info *delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
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if ((bio_data_dir(bio) == WRITE) && (dc->dev_write)) {
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bio_set_dev(bio, dc->dev_write->bdev);
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if (bio_sectors(bio))
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bio->bi_iter.bi_sector = dc->start_write +
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dm_target_offset(ti, bio->bi_iter.bi_sector);
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return delay_bio(dc, dc->write_delay, bio);
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if (bio_data_dir(bio) == WRITE) {
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c = &dc->write;
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} else {
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c = &dc->read;
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}
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delayed->class = c;
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bio_set_dev(bio, c->dev->bdev);
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if (bio_sectors(bio))
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bio->bi_iter.bi_sector = c->start + dm_target_offset(ti, bio->bi_iter.bi_sector);
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bio_set_dev(bio, dc->dev_read->bdev);
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bio->bi_iter.bi_sector = dc->start_read +
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dm_target_offset(ti, bio->bi_iter.bi_sector);
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return delay_bio(dc, dc->read_delay, bio);
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return delay_bio(dc, c, bio);
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}
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#define DMEMIT_DELAY_CLASS(c) \
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DMEMIT("%s %llu %u", (c)->dev->name, (unsigned long long)(c)->start, (c)->delay)
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static void delay_status(struct dm_target *ti, status_type_t type,
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unsigned status_flags, char *result, unsigned maxlen)
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{
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@ -307,17 +292,15 @@ static void delay_status(struct dm_target *ti, status_type_t type,
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switch (type) {
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case STATUSTYPE_INFO:
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DMEMIT("%u %u", dc->reads, dc->writes);
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DMEMIT("%u %u", dc->read.ops, dc->write.ops);
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break;
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case STATUSTYPE_TABLE:
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DMEMIT("%s %llu %u", dc->dev_read->name,
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(unsigned long long) dc->start_read,
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dc->read_delay);
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if (dc->dev_write)
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DMEMIT(" %s %llu %u", dc->dev_write->name,
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(unsigned long long) dc->start_write,
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dc->write_delay);
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DMEMIT_DELAY_CLASS(&dc->read);
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if (dc->argc >= 6) {
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DMEMIT(" ");
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DMEMIT_DELAY_CLASS(&dc->write);
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}
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break;
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}
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}
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@ -328,12 +311,12 @@ static int delay_iterate_devices(struct dm_target *ti,
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struct delay_c *dc = ti->private;
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int ret = 0;
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ret = fn(ti, dc->dev_read, dc->start_read, ti->len, data);
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ret = fn(ti, dc->read.dev, dc->read.start, ti->len, data);
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if (ret)
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goto out;
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ret = fn(ti, dc->write.dev, dc->write.start, ti->len, data);
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if (ret)
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goto out;
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if (dc->dev_write)
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ret = fn(ti, dc->dev_write, dc->start_write, ti->len, data);
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out:
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return ret;
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