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Commit fcedbb29 authored by Kimberly Brown's avatar Kimberly Brown Committed by Sasha Levin
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Drivers: hv: vmbus: Refactor chan->state if statement 



The chan->state "if statement" was introduced in commit 6712cc9c
("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: default avatarKimberly Brown <kimbrownkd@gmail.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 46fc1548

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);