From 8fea0c8fda30129b4168464975505d5dc9735ac1 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 4 Feb 2024 11:34:34 -1000 Subject: [PATCH] usb: core: hcd: Convert from tasklet to BH workqueue 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 Acked-by: Greg Kroah-Hartman Cc: Alan Stern Cc: linux-usb@vger.kernel.org --- 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; };