From 3d2e0711ecbfe2ddff8e48dc4772296719a73199 Mon Sep 17 00:00:00 2001 From: Long Li Date: Mon, 10 Mar 2025 15:12:01 -0700 Subject: [PATCH] uio_hv_generic: Set event for all channels on the device commit d062463edf1770427dc2d637df4088df4835aa47 upstream. Hyper-V may offer a non latency sensitive device with subchannels without monitor bit enabled. The decision is entirely on the Hyper-V host not configurable within guest. When a device has subchannels, also signal events for the subchannel if its monitor bit is disabled. This patch also removes the memory barrier when monitor bit is enabled as it is not necessary. The memory barrier is only needed between setting up interrupt mask and calling vmbus_set_event() when monitor bit is disabled. Signed-off-by: Long Li Reviewed-by: Michael Kelley Reviewed-by: Saurabh Sengar Link: https://lore.kernel.org/r/1741644721-20389-1-git-send-email-longli@linuxonhyperv.com Fixes: b15b7d2a1b09 ("uio_hv_generic: Let userspace take care of interrupt mask") Closes: https://bugs.debian.org/1120602 Signed-off-by: Naman Jain Signed-off-by: Greg Kroah-Hartman --- drivers/uio/uio_hv_generic.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c index 10d24f47c564..0d7ebf7b35e1 100644 --- a/drivers/uio/uio_hv_generic.c +++ b/drivers/uio/uio_hv_generic.c @@ -80,9 +80,15 @@ hv_uio_irqcontrol(struct uio_info *info, s32 irq_state) { struct hv_uio_private_data *pdata = info->priv; struct hv_device *dev = pdata->device; + struct vmbus_channel *primary, *sc; - dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state; - virt_mb(); + primary = dev->channel; + primary->inbound.ring_buffer->interrupt_mask = !irq_state; + + mutex_lock(&vmbus_connection.channel_mutex); + list_for_each_entry(sc, &primary->sc_list, sc_list) + sc->inbound.ring_buffer->interrupt_mask = !irq_state; + mutex_unlock(&vmbus_connection.channel_mutex); return 0; } @@ -93,11 +99,18 @@ hv_uio_irqcontrol(struct uio_info *info, s32 irq_state) static void hv_uio_channel_cb(void *context) { struct vmbus_channel *chan = context; - struct hv_device *hv_dev = chan->device_obj; - struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev); + struct hv_device *hv_dev; + struct hv_uio_private_data *pdata; virt_mb(); + /* + * The callback may come from a subchannel, in which case look + * for the hv device in the primary channel + */ + hv_dev = chan->primary_channel ? + chan->primary_channel->device_obj : chan->device_obj; + pdata = hv_get_drvdata(hv_dev); uio_event_notify(&pdata->info); }