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dm crypt: use wake_up_process() instead of a wait queue

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This is a small simplification of dm-crypt - use wake_up_process()
instead of a wait queue in a case where only one process may be
waiting.  dm-writecache uses a similar pattern.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka 2018-07-11 12:10:51 -04:00 committed by Mike Snitzer
parent a3fcf72531
commit c7329eff72
1 changed files with 10 additions and 15 deletions
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25
drivers/md/dm-crypt.c
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@ -144,7 +144,7 @@ struct crypt_config {
struct workqueue_struct *io_queue;
struct workqueue_struct *crypt_queue;
wait_queue_head_t write_thread_wait;
spinlock_t write_thread_lock;
struct task_struct *write_thread;
struct rb_root write_tree;
@ -1620,36 +1620,31 @@ static int dmcrypt_write(void *data)
struct rb_root write_tree;
struct blk_plug plug;
DECLARE_WAITQUEUE(wait, current);
spin_lock_irq(&cc->write_thread_wait.lock);
spin_lock_irq(&cc->write_thread_lock);
continue_locked:
if (!RB_EMPTY_ROOT(&cc->write_tree))
goto pop_from_list;
set_current_state(TASK_INTERRUPTIBLE);
__add_wait_queue(&cc->write_thread_wait, &wait);
spin_unlock_irq(&cc->write_thread_wait.lock);
spin_unlock_irq(&cc->write_thread_lock);
if (unlikely(kthread_should_stop())) {
set_current_state(TASK_RUNNING);
remove_wait_queue(&cc->write_thread_wait, &wait);
break;
}
schedule();
set_current_state(TASK_RUNNING);
spin_lock_irq(&cc->write_thread_wait.lock);
__remove_wait_queue(&cc->write_thread_wait, &wait);
spin_lock_irq(&cc->write_thread_lock);
goto continue_locked;
pop_from_list:
write_tree = cc->write_tree;
cc->write_tree = RB_ROOT;
spin_unlock_irq(&cc->write_thread_wait.lock);
spin_unlock_irq(&cc->write_thread_lock);
BUG_ON(rb_parent(write_tree.rb_node));
@ -1693,7 +1688,9 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
return;
}
spin_lock_irqsave(&cc->write_thread_wait.lock, flags);
spin_lock_irqsave(&cc->write_thread_lock, flags);
if (RB_EMPTY_ROOT(&cc->write_tree))
wake_up_process(cc->write_thread);
rbp = &cc->write_tree.rb_node;
parent = NULL;
sector = io->sector;
@ -1706,9 +1703,7 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async)
}
rb_link_node(&io->rb_node, parent, rbp);
rb_insert_color(&io->rb_node, &cc->write_tree);
wake_up_locked(&cc->write_thread_wait);
spin_unlock_irqrestore(&cc->write_thread_wait.lock, flags);
spin_unlock_irqrestore(&cc->write_thread_lock, flags);
}
static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
@ -2831,7 +2826,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad;
}
init_waitqueue_head(&cc->write_thread_wait);
spin_lock_init(&cc->write_thread_lock);
cc->write_tree = RB_ROOT;
cc->write_thread = kthread_create(dmcrypt_write, cc, "dmcrypt_write");