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Drivers: hv: vmbus: Refactor chan->state if statement

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The chan->state "if statement" was introduced in commit 6712cc9c22
("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>
This commit is contained in:
Kimberly Brown 2019-03-14 16:05:00 -04:00 committed by Sasha Levin
parent 46fc15487d
commit fcedbb293e
1 changed files with 12 additions and 3 deletions
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15
drivers/hv/vmbus_drv.c
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@ -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);