From 488ebe4c355fdead39dbb3f6a51329c16cbfcc60 Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Tue, 28 Nov 2017 12:40:31 -0600 Subject: 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: Mike Christie Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_user.c | 48 +++++++++++++++++++++++++++++++-------- 1 file changed, 39 insertions(+), 9 deletions(-) (limited to 'drivers/target') diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index a9f5c52e8b1d..2ccc8e61449b 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -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(); } -- cgit v1.2.3-59-g8ed1b