The only generic interface to execute asynchronously in the BH context is
tasklet; however, it's marked deprecated and has some design flaws. To
replace tasklets, BH workqueue support was recently added. A BH workqueue
behaves similarly to regular workqueues except that the queued work items
are executed in the BH context.
This patch converts usb hcd from tasklet to BH workqueue.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: linux-usb@xxxxxxxxxxxxxxx
---
drivers/usb/core/hcd.c | 23 ++++++++++++-----------
include/linux/usb/hcd.h | 2 +-
2 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 12b6dfeaf658..edf74458474a 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1664,9 +1664,10 @@ static void __usb_hcd_giveback_urb(struct urb *urb)
usb_put_urb(urb);
}
-static void usb_giveback_urb_bh(struct tasklet_struct *t)
+static void usb_giveback_urb_bh(struct work_struct *work)
{
- struct giveback_urb_bh *bh = from_tasklet(bh, t, bh);
+ struct giveback_urb_bh *bh =
+ container_of(work, struct giveback_urb_bh, bh);
struct list_head local_list;
spin_lock_irq(&bh->lock);
@@ -1691,9 +1692,9 @@ static void usb_giveback_urb_bh(struct tasklet_struct *t)
spin_lock_irq(&bh->lock);
if (!list_empty(&bh->head)) {
if (bh->high_prio)
- tasklet_hi_schedule(&bh->bh);
+ queue_work(system_bh_highpri_wq, &bh->bh);
else
- tasklet_schedule(&bh->bh);
+ queue_work(system_bh_wq, &bh->bh);
}
bh->running = false;
spin_unlock_irq(&bh->lock);
@@ -1706,7 +1707,7 @@ static void usb_giveback_urb_bh(struct tasklet_struct *t)
* @status: completion status code for the URB.
*
* Context: atomic. The completion callback is invoked in caller's context.
- * For HCDs with HCD_BH flag set, the completion callback is invoked in tasklet
+ * For HCDs with HCD_BH flag set, the completion callback is invoked in BH
* context (except for URBs submitted to the root hub which always complete in
* caller's context).
*
@@ -1725,7 +1726,7 @@ void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
struct giveback_urb_bh *bh;
bool running;
- /* pass status to tasklet via unlinked */
+ /* pass status to BH via unlinked */
if (likely(!urb->unlinked))
urb->unlinked = status;
@@ -1747,9 +1748,9 @@ void usb_hcd_giveback_urb(struct usb_hcd *hcd, struct urb *urb, int status)
if (running)
;
else if (bh->high_prio)
- tasklet_hi_schedule(&bh->bh);
+ queue_work(system_bh_highpri_wq, &bh->bh);
else
- tasklet_schedule(&bh->bh);
+ queue_work(system_bh_wq, &bh->bh);
}
EXPORT_SYMBOL_GPL(usb_hcd_giveback_urb);
@@ -2540,7 +2541,7 @@ static void init_giveback_urb_bh(struct giveback_urb_bh *bh)
spin_lock_init(&bh->lock);
INIT_LIST_HEAD(&bh->head);
- tasklet_setup(&bh->bh, usb_giveback_urb_bh);
+ INIT_WORK(&bh->bh, usb_giveback_urb_bh);
}
struct usb_hcd *__usb_create_hcd(const struct hc_driver *driver,
@@ -2926,7 +2927,7 @@ int usb_add_hcd(struct usb_hcd *hcd,
&& device_can_wakeup(&hcd->self.root_hub->dev))
dev_dbg(hcd->self.controller, "supports USB remote wakeup\n");
- /* initialize tasklets */
+ /* initialize BHs */
init_giveback_urb_bh(&hcd->high_prio_bh);
hcd->high_prio_bh.high_prio = true;
init_giveback_urb_bh(&hcd->low_prio_bh);
@@ -3036,7 +3037,7 @@ void usb_remove_hcd(struct usb_hcd *hcd)
mutex_unlock(&usb_bus_idr_lock);
/*
- * tasklet_kill() isn't needed here because:
+ * flush_work() isn't needed here because:
* - driver's disconnect() called from usb_disconnect() should
* make sure its URBs are completed during the disconnect()
* callback
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 00724b4f6e12..f698aac71de3 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -55,7 +55,7 @@ struct giveback_urb_bh {
bool high_prio;
spinlock_t lock;
struct list_head head;
- struct tasklet_struct bh;
+ struct work_struct bh;
struct usb_host_endpoint *completing_ep;
};
--
2.43.0
