This moves the expired command completion handling to
the unmap thread, so the next patch can use a mutex
in tcmu_check_expired_cmd.
Notes:
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) 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 <mchristi@xxxxxxxxxx>
---
drivers/target/target_core_user.c | 62 ++++++++++++++++++++++++++++++++-------
1 file changed, 51 insertions(+), 11 deletions(-)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index c40a043..40a9cf6 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -145,6 +145,7 @@ 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;
@@ -180,6 +181,10 @@ struct tcmu_cmd {
static struct task_struct *unmap_thread;
static wait_queue_head_t unmap_wait;
+
+static DEFINE_SPINLOCK(timed_out_udevs_lock);
+static LIST_HEAD(timed_out_udevs);
+
/*
* To avoid dead lock, the mutex locks order should always be:
*
@@ -1116,19 +1121,15 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data)
static void tcmu_device_timedout(unsigned long data)
{
struct tcmu_dev *udev = (struct tcmu_dev *)data;
- 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);
- /* Try to wake up the ummap thread */
- wake_up(&unmap_wait);
+ 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.
- */
+ wake_up(&unmap_wait);
}
static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
@@ -1172,6 +1173,7 @@ 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);
@@ -1396,6 +1398,11 @@ 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) {
@@ -2047,23 +2054,56 @@ static struct target_backend_ops tcmu_ops = {
.tb_dev_attrib_attrs = NULL,
};
+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 int unmap_thread_fn(void *data)
{
struct tcmu_dev *udev, *tmp;
loff_t off;
uint32_t start, end, block;
static uint32_t free_blocks;
+ bool has_timed_out_devs;
while (!kthread_should_stop()) {
DEFINE_WAIT(__wait);
prepare_to_wait(&unmap_wait, &__wait, TASK_INTERRUPTIBLE);
- schedule();
+
+ spin_lock_bh(&timed_out_udevs_lock);
+ has_timed_out_devs = true;
+ if (list_empty(&timed_out_udevs))
+ has_timed_out_devs = false;
+ spin_unlock_bh(&timed_out_udevs_lock);
+
+ if (!has_timed_out_devs)
+ schedule();
+
finish_wait(&unmap_wait, &__wait);
if (kthread_should_stop())
break;
+ check_timedout_devices();
+
mutex_lock(&root_udev_mutex);
list_for_each_entry(udev, &root_udev, node) {
mutex_lock(&udev->cmdr_lock);
--
2.7.2
--
To unsubscribe from this list: send the line "unsubscribe target-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
