From b6aeeddef68deec9d603e455d163e3b41951f2d9 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sat, 20 Apr 2019 13:21:53 +0200 Subject: [PATCH] HID: logitech-dj: add logi_dj_recv_queue_unknown_work helper Add a logi_dj_recv_queue_unknown_work helper and implement query rate-limiting inside this helper. The motivations behind this are: 1) We need to queue workitems for reports with no place to forward them from more places with the upcoming non-unifying receiver support, hence the addition of the helper function. 2) When we've missed a pairing info report (or there is a race between the report and input-events) and the input report is e.g. from a mouse being moved, we will get a lot of these before we've finished (re-) querying and enumerating the devices, hence the rate-limiting. Note this also removes the: if (!djrcv_dev->paired_dj_devices[hidpp_report->device_index]) check previously guarding the sending of an unknown workitem, the caller of logi_dj_recv_queue_notification already does this check before calling logi_dj_recv_queue_notification. Signed-off-by: Hans de Goede Signed-off-by: Benjamin Tissoires --- drivers/hid/hid-logitech-dj.c | 45 ++++++++++++++++++++++++++++--------------- 1 file changed, 30 insertions(+), 15 deletions(-) diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c index a3ad100..ac0d00e 100644 --- a/drivers/hid/hid-logitech-dj.c +++ b/drivers/hid/hid-logitech-dj.c @@ -128,6 +128,7 @@ struct dj_receiver_dev { struct kref kref; struct work_struct work; struct kfifo notif_fifo; + unsigned long last_query; /* in jiffies */ bool ready; spinlock_t lock; }; @@ -458,6 +459,7 @@ static struct dj_receiver_dev *dj_get_receiver_dev(struct hid_device *hdev, } kref_init(&djrcv_dev->kref); list_add_tail(&djrcv_dev->list, &dj_hdev_list); + djrcv_dev->last_query = jiffies; } if (application == HID_GD_KEYBOARD) @@ -637,6 +639,30 @@ static void delayedwork_callback(struct work_struct *work) } } +/* + * Sometimes we receive reports for which we do not have a paired dj_device + * associated with the device_index or report-type to forward the report to. + * This means that the original "device paired" notification corresponding + * to the dj_device never arrived to this driver. Possible reasons for this are: + * 1) hid-core discards all packets coming from a device during probe(). + * 2) if the receiver is plugged into a KVM switch then the pairing reports + * are only forwarded to it if the focus is on this PC. + * This function deals with this by re-asking the receiver for the list of + * connected devices in the delayed work callback. + * This function MUST be called with djrcv->lock held. + */ +static void logi_dj_recv_queue_unknown_work(struct dj_receiver_dev *djrcv_dev) +{ + struct dj_workitem workitem = { .type = WORKITEM_TYPE_UNKNOWN }; + + /* Rate limit queries done because of unhandeled reports to 2/sec */ + if (time_before(jiffies, djrcv_dev->last_query + HZ / 2)) + return; + + kfifo_in(&djrcv_dev->notif_fifo, &workitem, sizeof(workitem)); + schedule_work(&djrcv_dev->work); +} + static void logi_dj_recv_queue_notification(struct dj_receiver_dev *djrcv_dev, struct dj_report *dj_report) { @@ -666,21 +692,8 @@ static void logi_dj_recv_queue_notification(struct dj_receiver_dev *djrcv_dev, workitem.type = WORKITEM_TYPE_UNPAIRED; break; default: - /* A normal report (i. e. not belonging to a pair/unpair notification) - * arriving here, means that the report arrived but we did not have a - * paired dj_device associated to the report's device_index, this - * means that the original "device paired" notification corresponding - * to this dj_device never arrived to this driver. The reason is that - * hid-core discards all packets coming from a device while probe() is - * executing. */ - if (!djrcv_dev->paired_dj_devices[dj_report->device_index]) { - /* - * ok, we don't know the device, just re-ask the - * receiver for the list of connected devices in - * the delayed work callback. - */ - workitem.type = WORKITEM_TYPE_UNKNOWN; - } + logi_dj_recv_queue_unknown_work(djrcv_dev); + return; } kfifo_in(&djrcv_dev->notif_fifo, &workitem, sizeof(workitem)); @@ -776,6 +789,8 @@ static int logi_dj_recv_query_paired_devices(struct dj_receiver_dev *djrcv_dev) struct dj_report *dj_report; int retval; + djrcv_dev->last_query = jiffies; + dj_report = kzalloc(sizeof(struct dj_report), GFP_KERNEL); if (!dj_report) return -ENOMEM; -- 2.7.4