diff options
| author | Andrea Parri (Microsoft) <parri.andrea@gmail.com> | 2022-04-19 14:23:22 +0200 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2022-04-25 15:51:12 +0000 |
| commit | b03afa57c65e1e045e02df49777e953742745f4c (patch) | |
| tree | 5e53d07bdea47f83db7555faa348e79695a97261 /drivers/hv/ring_buffer.c | |
| parent | de5ddb7d44347ad8b00533c1850a4e2e636a1ce9 (diff) | |
Drivers: hv: vmbus: Introduce vmbus_sendpacket_getid()
The function can be used to send a VMbus packet and retrieve the
corresponding transaction ID. It will be used by hv_pci.
No functional change.
Suggested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220419122325.10078-4-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'drivers/hv/ring_buffer.c')
| -rw-r--r-- | drivers/hv/ring_buffer.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 3d215d9dec43..e101b11f95e5 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -283,7 +283,7 @@ void hv_ringbuffer_cleanup(struct hv_ring_buffer_info *ring_info) /* Write to the ring buffer. */ int hv_ringbuffer_write(struct vmbus_channel *channel, const struct kvec *kv_list, u32 kv_count, - u64 requestid) + u64 requestid, u64 *trans_id) { int i; u32 bytes_avail_towrite; @@ -294,7 +294,7 @@ int hv_ringbuffer_write(struct vmbus_channel *channel, unsigned long flags; struct hv_ring_buffer_info *outring_info = &channel->outbound; struct vmpacket_descriptor *desc = kv_list[0].iov_base; - u64 rqst_id = VMBUS_NO_RQSTOR; + u64 __trans_id, rqst_id = VMBUS_NO_RQSTOR; if (channel->rescind) return -ENODEV; @@ -353,7 +353,15 @@ int hv_ringbuffer_write(struct vmbus_channel *channel, } } desc = hv_get_ring_buffer(outring_info) + old_write; - desc->trans_id = (rqst_id == VMBUS_NO_RQSTOR) ? requestid : rqst_id; + __trans_id = (rqst_id == VMBUS_NO_RQSTOR) ? requestid : rqst_id; + /* + * Ensure the compiler doesn't generate code that reads the value of + * the transaction ID from the ring buffer, which is shared with the + * Hyper-V host and subject to being changed at any time. + */ + WRITE_ONCE(desc->trans_id, __trans_id); + if (trans_id) + *trans_id = __trans_id; /* Set previous packet start */ prev_indices = hv_get_ring_bufferindices(outring_info); |