From ca3cda6fcf1e922213a0cc58e708ffb999151db3 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Tue, 9 Jan 2018 12:57:32 -0800 Subject: [PATCH] uio_hv_generic: add rescind support When host rescinds the device, the UIO driver will clear the interrupt state and notify application. The read (or write) on the interrupt FD will then fail with -EIO. This is simpler than adding lots extra uevent stuff inside UIO. Signed-off-by: Stephen Hemminger Signed-off-by: Greg Kroah-Hartman --- Documentation/driver-api/uio-howto.rst | 4 ++++ drivers/uio/uio_hv_generic.c | 19 +++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/Documentation/driver-api/uio-howto.rst b/Documentation/driver-api/uio-howto.rst index 97e6435..693e3bd 100644 --- a/Documentation/driver-api/uio-howto.rst +++ b/Documentation/driver-api/uio-howto.rst @@ -698,6 +698,10 @@ prevents the device from generating further interrupts until the bit is cleared. The userspace driver should clear this bit before blocking and waiting for more interrupts. +When host rescinds a device, the interrupt file descriptor is marked down +and any reads of the interrupt file descriptor will return -EIO. Similar +to a closed socket or disconnected serial device. + The vmbus device regions are mapped into uio device resources: 0) Channel ring buffers: guest to host and host to guest 1) Guest to host interrupt signalling pages diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c index ee6d862..8c6b04a 100644 --- a/drivers/uio/uio_hv_generic.c +++ b/drivers/uio/uio_hv_generic.c @@ -103,6 +103,23 @@ static void hv_uio_channel_cb(void *context) uio_event_notify(&pdata->info); } +/* + * Callback from vmbus_event when channel is rescinded. + */ +static void hv_uio_rescind(struct vmbus_channel *channel) +{ + struct hv_device *hv_dev = channel->primary_channel->device_obj; + struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev); + + /* + * Turn off the interrupt file handle + * Next read for event will return -EIO + */ + pdata->info.irq = 0; + + /* Wake up reader */ + uio_event_notify(&pdata->info); +} static void hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata) @@ -218,6 +235,8 @@ hv_uio_probe(struct hv_device *dev, goto fail_close; } + vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind); + hv_set_drvdata(dev, pdata); return 0; -- 2.7.4