Commit e7e97dd8 authored Dec 07, 2016 by K. Y. Srinivasan Committed by Greg Kroah-Hartman Jan 10, 2017

Drivers: hv: vmbus: Prevent sending data on a rescinded channel

After the channel is rescinded, the host does not read from the rescinded channel.
Fail writes to a channel that has already been rescinded. If we permit writes on a
rescinded channel, since the host will not respond we will have situations where
we will be unable to unload vmbus drivers that cannot have any outstanding requests
to the host at the point they are unoaded.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 56ef6718

drivers/hv/ring_buffer.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -298,6 +298,9 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
		unsigned long flags = 0;
		struct hv_ring_buffer_info *outring_info = &channel->outbound;

		if (channel->rescind)
		return -ENODEV;

		for (i = 0; i < kv_count; i++)
		totalbytes_towrite += kv_list[i].iov_len;

		@@ -350,6 +353,10 @@ int hv_ringbuffer_write(struct vmbus_channel *channel,
		spin_unlock_irqrestore(&outring_info->ring_lock, flags);

		hv_signal_on_write(old_write, channel, kick_q);

		if (channel->rescind)
		return -ENODEV;

		return 0;
		}

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