The chan->state "if statement" was introduced in commit 6712cc9c2211
("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 <kimbrow...@gmail.com>
---
drivers/hv/vmbus_drv.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index f290401f97e5..b02bcf1a9380 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1434,9 +1434,6 @@ 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);
}
@@ -1448,6 +1445,9 @@ 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);
@@ -1456,6 +1456,9 @@ 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);
@@ -1464,6 +1467,9 @@ 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);
@@ -1472,6 +1478,9 @@ 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);
--
2.17.1
