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Commit 488ebe4c authored by Mike Christie's avatar Mike Christie Committed by Nicholas Bellinger
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tcmu: move expired command completion to unmap thread 



This moves the expired command completion handling to
the unmap wq, so the next patch can use a mutex
in tcmu_check_expired_cmd.

Note:
tcmu_device_timedout's use of spin_lock_irq was not needed.
The commands_lock is used between thread context (tcmu_queue_cmd_ring
and tcmu_irqcontrol (even though this is named irqcontrol it is not
run in irq context)) and timer/bh context. In the timer/bh context
bhs are disabled, so you need to use the _bh lock calls from the
thread context callers.

Signed-off-by: default avatarMike Christie <mchristi@redhat.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 9972cebb

drivers/target/target_core_user.c

+39 −9
Original line number Diff line number Diff line
@@ -143,6 +143,7 @@ struct tcmu_dev { 


	struct timer_list timeout;

	unsigned int cmd_time_out;

	struct list_head timedout_entry;



	spinlock_t nl_cmd_lock;

	struct tcmu_nl_cmd curr_nl_cmd;
@@ -179,6 +180,9 @@ struct tcmu_cmd { 
static DEFINE_MUTEX(root_udev_mutex);

static LIST_HEAD(root_udev);



static DEFINE_SPINLOCK(timed_out_udevs_lock);

static LIST_HEAD(timed_out_udevs);



static atomic_t global_db_count = ATOMIC_INIT(0);

static struct work_struct tcmu_unmap_work;
@@ -1057,18 +1061,15 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data) 
static void tcmu_device_timedout(struct timer_list *t)

{

	struct tcmu_dev *udev = from_timer(udev, t, timeout);

	unsigned long flags;



	spin_lock_irqsave(&udev->commands_lock, flags);

	idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);

	spin_unlock_irqrestore(&udev->commands_lock, flags);

	pr_debug("%s cmd timeout has expired\n", udev->name);



	schedule_work(&tcmu_unmap_work);

	spin_lock(&timed_out_udevs_lock);

	if (list_empty(&udev->timedout_entry))

		list_add_tail(&udev->timedout_entry, &timed_out_udevs);

	spin_unlock(&timed_out_udevs_lock);



	/*

	 * We don't need to wakeup threads on wait_cmdr since they have their

	 * own timeout.

	 */

	schedule_work(&tcmu_unmap_work);

}



static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
@@ -1112,6 +1113,7 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name) 
	init_waitqueue_head(&udev->wait_cmdr);

	mutex_init(&udev->cmdr_lock);



	INIT_LIST_HEAD(&udev->timedout_entry);

	idr_init(&udev->commands);

	spin_lock_init(&udev->commands_lock);
@@ -1325,6 +1327,11 @@ static void tcmu_dev_kref_release(struct kref *kref) 
	vfree(udev->mb_addr);

	udev->mb_addr = NULL;



	spin_lock_bh(&timed_out_udevs_lock);

	if (!list_empty(&udev->timedout_entry))

		list_del(&udev->timedout_entry);

	spin_unlock_bh(&timed_out_udevs_lock);



	/* Upper layer should drain all requests before calling this */

	spin_lock_irq(&udev->commands_lock);

	idr_for_each_entry(&udev->commands, cmd, i) {
@@ -2041,8 +2048,31 @@ static void run_cmdr_queues(void) 
	mutex_unlock(&root_udev_mutex);

}



static void check_timedout_devices(void)

{

	struct tcmu_dev *udev, *tmp_dev;

	LIST_HEAD(devs);



	spin_lock_bh(&timed_out_udevs_lock);

	list_splice_init(&timed_out_udevs, &devs);



	list_for_each_entry_safe(udev, tmp_dev, &devs, timedout_entry) {

		list_del_init(&udev->timedout_entry);

		spin_unlock_bh(&timed_out_udevs_lock);



		spin_lock(&udev->commands_lock);

		idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);

		spin_unlock(&udev->commands_lock);



		spin_lock_bh(&timed_out_udevs_lock);

	}



	spin_unlock_bh(&timed_out_udevs_lock);

}



static void tcmu_unmap_work_fn(struct work_struct *work)

{

	check_timedout_devices();

	find_free_blocks();

	run_cmdr_queues();

}