From: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
To deal with the merge conflict between net-next and char-misc trees,
revert commit bb08d431a914 from char-misc tree. This commit can be rebased
and applied once net-next picks up char-misc changes.
---
include/linux/hyperv.h | 32 +++++++++++++++++++++-----------
1 files changed, 21 insertions(+), 11 deletions(-)
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index c877e79..613074e 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1492,23 +1492,31 @@ static inline struct vmpacket_descriptor *
get_next_pkt_raw(struct vmbus_channel *channel)
{
struct hv_ring_buffer_info *ring_info = &channel->inbound;
- u32 priv_read_loc = ring_info->priv_read_index;
+ u32 read_loc = ring_info->priv_read_index;
void *ring_buffer = hv_get_ring_buffer(ring_info);
+ struct vmpacket_descriptor *cur_desc;
+ u32 packetlen;
u32 dsize = ring_info->ring_datasize;
- /*
- * delta is the difference between what is available to read and
- * what was already consumed in place. We commit read index after
- * the whole batch is processed.
- */
- u32 delta = priv_read_loc >= ring_info->ring_buffer->read_index ?
- priv_read_loc - ring_info->ring_buffer->read_index :
- (dsize - ring_info->ring_buffer->read_index) + priv_read_loc;
+ u32 delta = read_loc - ring_info->ring_buffer->read_index;
u32 bytes_avail_toread = (hv_get_bytes_to_read(ring_info) - delta);
if (bytes_avail_toread < sizeof(struct vmpacket_descriptor))
return NULL;
- return ring_buffer + priv_read_loc;
+ if ((read_loc + sizeof(*cur_desc)) > dsize)
+ return NULL;
+
+ cur_desc = ring_buffer + read_loc;
+ packetlen = cur_desc->len8 << 3;
+
+ /*
+ * If the packet under consideration is wrapping around,
+ * return failure.
+ */
+ if ((read_loc + packetlen + VMBUS_PKT_TRAILER) > (dsize - 1))
+ return NULL;
+
+ return cur_desc;
}
/*
@@ -1520,14 +1528,16 @@ static inline void put_pkt_raw(struct vmbus_channel *channel,
struct vmpacket_descriptor *desc)
{
struct hv_ring_buffer_info *ring_info = &channel->inbound;
+ u32 read_loc = ring_info->priv_read_index;
u32 packetlen = desc->len8 << 3;
u32 dsize = ring_info->ring_datasize;
+ if ((read_loc + packetlen + VMBUS_PKT_TRAILER) > dsize)
+ BUG();
/*
* Include the packet trailer.
*/
ring_info->priv_read_index += packetlen + VMBUS_PKT_TRAILER;
- ring_info->priv_read_index %= dsize;
}
/*
--
1.7.4.1
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