Drivers: hv: vmbus: Refactor chan->state if statement (fcedbb29) · Commits · 戴 / test

The chan->state "if statement" was introduced in commit ("vmbus: don't return values for uninitalized channels"). That commit states that the purpose of the chan->state "if statement" is to prevent returning garbage or causing a kernel OOPS when the channel ring buffer is not initialized. The changes in this patch provide the same protection. Refactor the chan->state “if statement” in vmbus_chan_attr_show(): - Instead of checking the channel state in the "if statement", check whether the channel ring buffer pointer is NULL. Checking the ring buffer pointer makes this code consistent with hv_ringbuffer_get_debuginfo(). - Move the "if statement" to the four "_show" functions that access a channel ring buffer. Only four of the channel-level "_show" functions access a ring buffer. The ring buffer pointer does not need to be checked before calling the other "_show" functions, and moving the ring buffer pointer "if statement" to the "_show" functions that access a ring buffer makes the purpose of the "if statement" clear. Signed-off-by:

Kimberly Brown <kimbrownkd@gmail.com> Reviewed-by:

Michael Kelley <mikelley@microsoft.com> Signed-off-by:

Sasha Levin <sashal@kernel.org>

drivers/hv/vmbus_drv.c

+12 −3

Original line number	Diff line number	Diff line
		@@ -1435,9 +1435,6 @@ static ssize_t vmbus_chan_attr_show(struct kobject *kobj,
		if (!attribute->show)
		return -EIO;

		if (chan->state != CHANNEL_OPENED_STATE)
		return -EINVAL;

		return attribute->show(chan, buf);
		}

		@@ -1449,6 +1446,9 @@ static ssize_t out_mask_show(const struct vmbus_channel channel, char buf)
		{
		const struct hv_ring_buffer_info *rbi = &channel->outbound;

		if (!rbi->ring_buffer)
		return -EINVAL;

		return sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask);
		}
		static VMBUS_CHAN_ATTR_RO(out_mask);
		@@ -1457,6 +1457,9 @@ static ssize_t in_mask_show(const struct vmbus_channel channel, char buf)
		{
		const struct hv_ring_buffer_info *rbi = &channel->inbound;

		if (!rbi->ring_buffer)
		return -EINVAL;

		return sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask);
		}
		static VMBUS_CHAN_ATTR_RO(in_mask);
		@@ -1465,6 +1468,9 @@ static ssize_t read_avail_show(const struct vmbus_channel channel, char buf)
		{
		const struct hv_ring_buffer_info *rbi = &channel->inbound;

		if (!rbi->ring_buffer)
		return -EINVAL;

		return sprintf(buf, "%u\n", hv_get_bytes_to_read(rbi));
		}
		static VMBUS_CHAN_ATTR_RO(read_avail);
		@@ -1473,6 +1479,9 @@ static ssize_t write_avail_show(const struct vmbus_channel channel, char buf)
		{
		const struct hv_ring_buffer_info *rbi = &channel->outbound;

		if (!rbi->ring_buffer)
		return -EINVAL;

		return sprintf(buf, "%u\n", hv_get_bytes_to_write(rbi));
		}
		static VMBUS_CHAN_ATTR_RO(write_avail);

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