#include <linux/writeback.h>
#include <linux/completion.h>
#include <linux/highmem.h>
-#include <linux/kthread.h>
#include <linux/splice.h>
#include <linux/sysfs.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.h>
+#define LOOP_IDLE_WORKER_TIMEOUT (60 * HZ)
+
static DEFINE_IDR(loop_index_idr);
static DEFINE_MUTEX(loop_ctl_mutex);
q->limits.discard_alignment = 0;
}
-static void loop_unprepare_queue(struct loop_device *lo)
+struct loop_worker {
+ struct rb_node rb_node;
+ struct work_struct work;
+ struct list_head cmd_list;
+ struct list_head idle_list;
+ struct loop_device *lo;
+ struct cgroup_subsys_state *css;
+ unsigned long last_ran_at;
+};
+
+static void loop_workfn(struct work_struct *work);
+static void loop_rootcg_workfn(struct work_struct *work);
+static void loop_free_idle_workers(struct timer_list *timer);
+
+#ifdef CONFIG_BLK_CGROUP
+static inline int queue_on_root_worker(struct cgroup_subsys_state *css)
{
- kthread_flush_worker(&lo->worker);
- kthread_stop(lo->worker_task);
+ return !css || css == blkcg_root_css;
}
-
-static int loop_kthread_worker_fn(void *worker_ptr)
+#else
+static inline int queue_on_root_worker(struct cgroup_subsys_state *css)
{
- current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO;
- return kthread_worker_fn(worker_ptr);
+ return !css;
}
+#endif
-static int loop_prepare_queue(struct loop_device *lo)
+static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd)
{
- kthread_init_worker(&lo->worker);
- lo->worker_task = kthread_run(loop_kthread_worker_fn,
- &lo->worker, "loop%d", lo->lo_number);
- if (IS_ERR(lo->worker_task))
- return -ENOMEM;
- set_user_nice(lo->worker_task, MIN_NICE);
- return 0;
+ struct rb_node **node = &(lo->worker_tree.rb_node), *parent = NULL;
+ struct loop_worker *cur_worker, *worker = NULL;
+ struct work_struct *work;
+ struct list_head *cmd_list;
+
+ spin_lock_irq(&lo->lo_work_lock);
+
+ if (queue_on_root_worker(cmd->css))
+ goto queue_work;
+
+ node = &lo->worker_tree.rb_node;
+
+ while (*node) {
+ parent = *node;
+ cur_worker = container_of(*node, struct loop_worker, rb_node);
+ if (cur_worker->css == cmd->css) {
+ worker = cur_worker;
+ break;
+ } else if ((long)cur_worker->css < (long)cmd->css) {
+ node = &(*node)->rb_left;
+ } else {
+ node = &(*node)->rb_right;
+ }
+ }
+ if (worker)
+ goto queue_work;
+
+ worker = kzalloc(sizeof(struct loop_worker), GFP_NOWAIT | __GFP_NOWARN);
+ /*
+ * In the event we cannot allocate a worker, just queue on the
+ * rootcg worker
+ */
+ if (!worker)
+ goto queue_work;
+
+ worker->css = cmd->css;
+ css_get(worker->css);
+ INIT_WORK(&worker->work, loop_workfn);
+ INIT_LIST_HEAD(&worker->cmd_list);
+ INIT_LIST_HEAD(&worker->idle_list);
+ worker->lo = lo;
+ rb_link_node(&worker->rb_node, parent, node);
+ rb_insert_color(&worker->rb_node, &lo->worker_tree);
+queue_work:
+ if (worker) {
+ /*
+ * We need to remove from the idle list here while
+ * holding the lock so that the idle timer doesn't
+ * free the worker
+ */
+ if (!list_empty(&worker->idle_list))
+ list_del_init(&worker->idle_list);
+ work = &worker->work;
+ cmd_list = &worker->cmd_list;
+ } else {
+ work = &lo->rootcg_work;
+ cmd_list = &lo->rootcg_cmd_list;
+ }
+ list_add_tail(&cmd->list_entry, cmd_list);
+ queue_work(lo->workqueue, work);
+ spin_unlock_irq(&lo->lo_work_lock);
}
static void loop_update_rotational(struct loop_device *lo)
!file->f_op->write_iter)
lo->lo_flags |= LO_FLAGS_READ_ONLY;
- error = loop_prepare_queue(lo);
- if (error)
+ lo->workqueue = alloc_workqueue("loop%d",
+ WQ_UNBOUND | WQ_FREEZABLE,
+ 0,
+ lo->lo_number);
+ if (!lo->workqueue) {
+ error = -ENOMEM;
goto out_unlock;
+ }
set_disk_ro(lo->lo_disk, (lo->lo_flags & LO_FLAGS_READ_ONLY) != 0);
+ INIT_WORK(&lo->rootcg_work, loop_rootcg_workfn);
+ INIT_LIST_HEAD(&lo->rootcg_cmd_list);
+ INIT_LIST_HEAD(&lo->idle_worker_list);
+ lo->worker_tree = RB_ROOT;
+ timer_setup(&lo->timer, loop_free_idle_workers,
+ TIMER_DEFERRABLE);
lo->use_dio = lo->lo_flags & LO_FLAGS_DIRECT_IO;
lo->lo_device = bdev;
lo->lo_backing_file = file;
int err = 0;
bool partscan = false;
int lo_number;
+ struct loop_worker *pos, *worker;
mutex_lock(&lo->lo_mutex);
if (WARN_ON_ONCE(lo->lo_state != Lo_rundown)) {
/* freeze request queue during the transition */
blk_mq_freeze_queue(lo->lo_queue);
+ destroy_workqueue(lo->workqueue);
+ spin_lock_irq(&lo->lo_work_lock);
+ list_for_each_entry_safe(worker, pos, &lo->idle_worker_list,
+ idle_list) {
+ list_del(&worker->idle_list);
+ rb_erase(&worker->rb_node, &lo->worker_tree);
+ css_put(worker->css);
+ kfree(worker);
+ }
+ spin_unlock_irq(&lo->lo_work_lock);
+ del_timer_sync(&lo->timer);
+
spin_lock_irq(&lo->lo_lock);
lo->lo_backing_file = NULL;
spin_unlock_irq(&lo->lo_lock);
partscan = lo->lo_flags & LO_FLAGS_PARTSCAN && bdev;
lo_number = lo->lo_number;
- loop_unprepare_queue(lo);
out_unlock:
mutex_unlock(&lo->lo_mutex);
if (partscan) {
} else
#endif
cmd->css = NULL;
- kthread_queue_work(&lo->worker, &cmd->work);
+ loop_queue_work(lo, cmd);
return BLK_STS_OK;
}
}
}
-static void loop_queue_work(struct kthread_work *work)
+static void loop_set_timer(struct loop_device *lo)
+{
+ timer_reduce(&lo->timer, jiffies + LOOP_IDLE_WORKER_TIMEOUT);
+}
+
+static void loop_process_work(struct loop_worker *worker,
+ struct list_head *cmd_list, struct loop_device *lo)
{
- struct loop_cmd *cmd =
- container_of(work, struct loop_cmd, work);
+ int orig_flags = current->flags;
+ struct loop_cmd *cmd;
- loop_handle_cmd(cmd);
+ current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO;
+ spin_lock_irq(&lo->lo_work_lock);
+ while (!list_empty(cmd_list)) {
+ cmd = container_of(
+ cmd_list->next, struct loop_cmd, list_entry);
+ list_del(cmd_list->next);
+ spin_unlock_irq(&lo->lo_work_lock);
+
+ loop_handle_cmd(cmd);
+ cond_resched();
+
+ spin_lock_irq(&lo->lo_work_lock);
+ }
+
+ /*
+ * We only add to the idle list if there are no pending cmds
+ * *and* the worker will not run again which ensures that it
+ * is safe to free any worker on the idle list
+ */
+ if (worker && !work_pending(&worker->work)) {
+ worker->last_ran_at = jiffies;
+ list_add_tail(&worker->idle_list, &lo->idle_worker_list);
+ loop_set_timer(lo);
+ }
+ spin_unlock_irq(&lo->lo_work_lock);
+ current->flags = orig_flags;
}
-static int loop_init_request(struct blk_mq_tag_set *set, struct request *rq,
- unsigned int hctx_idx, unsigned int numa_node)
+static void loop_workfn(struct work_struct *work)
{
- struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
+ struct loop_worker *worker =
+ container_of(work, struct loop_worker, work);
+ loop_process_work(worker, &worker->cmd_list, worker->lo);
+}
- kthread_init_work(&cmd->work, loop_queue_work);
- return 0;
+static void loop_rootcg_workfn(struct work_struct *work)
+{
+ struct loop_device *lo =
+ container_of(work, struct loop_device, rootcg_work);
+ loop_process_work(NULL, &lo->rootcg_cmd_list, lo);
+}
+
+static void loop_free_idle_workers(struct timer_list *timer)
+{
+ struct loop_device *lo = container_of(timer, struct loop_device, timer);
+ struct loop_worker *pos, *worker;
+
+ spin_lock_irq(&lo->lo_work_lock);
+ list_for_each_entry_safe(worker, pos, &lo->idle_worker_list,
+ idle_list) {
+ if (time_is_after_jiffies(worker->last_ran_at +
+ LOOP_IDLE_WORKER_TIMEOUT))
+ break;
+ list_del(&worker->idle_list);
+ rb_erase(&worker->rb_node, &lo->worker_tree);
+ css_put(worker->css);
+ kfree(worker);
+ }
+ if (!list_empty(&lo->idle_worker_list))
+ loop_set_timer(lo);
+ spin_unlock_irq(&lo->lo_work_lock);
}
static const struct blk_mq_ops loop_mq_ops = {
.queue_rq = loop_queue_rq,
- .init_request = loop_init_request,
.complete = lo_complete_rq,
};
mutex_init(&lo->lo_mutex);
lo->lo_number = i;
spin_lock_init(&lo->lo_lock);
+ spin_lock_init(&lo->lo_work_lock);
disk->major = LOOP_MAJOR;
disk->first_minor = i << part_shift;
disk->fops = &lo_fops;
projects / linux-2.6-microblaze.git / commitdiff