From bb00788bd62778ef80a97d67a0e3c569ac6be06f Mon Sep 17 00:00:00 2001 From: Michael Grzeschik Date: Mon, 11 Sep 2023 16:05:30 +0200 Subject: [PATCH] usb: gadget: uvc: rework pump worker to avoid while loop The uvc_video_enable function is calling cancel_work_sync which will be blocking as long as new requests will be queued with the while loop. To ensure an earlier stop in the pumping loop in this particular case we rework the worker to requeue itself on every requests. Since the worker is already running prioritized, the scheduling overhad did not have real impact on the performance. Signed-off-by: Michael Grzeschik Link: https://lore.kernel.org/r/20230911140530.2995138-4-m.grzeschik@pengutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/uvc_video.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c index c48c904f500ff..97d875c27dcf9 100644 --- a/drivers/usb/gadget/function/uvc_video.c +++ b/drivers/usb/gadget/function/uvc_video.c @@ -397,7 +397,7 @@ static void uvcg_video_pump(struct work_struct *work) bool buf_done; int ret; - while (video->ep->enabled && uvc->state == UVC_STATE_STREAMING) { + if (video->ep->enabled && uvc->state == UVC_STATE_STREAMING) { /* * Retrieve the first available USB request, protected by the * request lock. @@ -409,6 +409,11 @@ static void uvcg_video_pump(struct work_struct *work) } req = list_first_entry(&video->req_free, struct usb_request, list); + if (!req) { + spin_unlock_irqrestore(&video->req_lock, flags); + return; + } + list_del(&req->list); spin_unlock_irqrestore(&video->req_lock, flags); @@ -437,7 +442,7 @@ static void uvcg_video_pump(struct work_struct *work) * further. */ spin_unlock_irqrestore(&queue->irqlock, flags); - break; + goto out; } /* @@ -470,20 +475,23 @@ static void uvcg_video_pump(struct work_struct *work) /* Queue the USB request */ ret = uvcg_video_ep_queue(video, req); spin_unlock_irqrestore(&queue->irqlock, flags); - if (ret < 0) { uvcg_queue_cancel(queue, 0); - break; + goto out; } /* Endpoint now owns the request */ req = NULL; video->req_int_count++; + } else { + return; } - if (!req) - return; + if (uvc->state == UVC_STATE_STREAMING) + queue_work(video->async_wq, &video->pump); + return; +out: spin_lock_irqsave(&video->req_lock, flags); list_add_tail(&req->list, &video->req_free); spin_unlock_irqrestore(&video->req_lock, flags); -- 2.30.2