[RFC PATCH v3 2/8] vhost: annotate virtqueue access lock

[David Marchand]

This change simply annotates existing paths of the code leading to
manipulations of the vq->access_lock.

One small change is required: vhost_poll_enqueue_completed was getting
a queue_id to get hold of the vq, while its callers already knew of
the vq. For the annotation sake, vq is now directly passed.

vhost_user_lock_all_queue_pairs and vhost_user_unlock_all_queue_pairs
are skipped since vq->access_lock are conditionally held.

Signed-off-by: David Marchand <david.marchand at redhat.com>
---
 lib/vhost/vhost.h      |  2 ++
 lib/vhost/vhost_user.c |  2 ++
 lib/vhost/virtio_net.c | 16 ++++++++++++----
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
index a9edc271aa..4a0aa35306 100644
--- a/lib/vhost/vhost.h
+++ b/lib/vhost/vhost.h
@@ -834,6 +834,7 @@ vhost_need_event(uint16_t event_idx, uint16_t new_idx, uint16_t old)
 
 static __rte_always_inline void
 vhost_vring_call_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
 	/* Flush used->idx update before we read avail->flags. */
 	rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
@@ -872,6 +873,7 @@ vhost_vring_call_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
 
 static __rte_always_inline void
 vhost_vring_call_packed(struct virtio_net *dev, struct vhost_virtqueue *vq)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
 	uint16_t old, new, off, off_wrap;
 	bool signalled_used_valid, kick = false;
diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index 1d390677fa..dfa24fec09 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -2909,6 +2909,7 @@ vhost_user_check_and_alloc_queue_pair(struct virtio_net *dev,
 
 static void
 vhost_user_lock_all_queue_pairs(struct virtio_net *dev)
+	__rte_no_thread_safety_analysis
 {
 	unsigned int i = 0;
 	unsigned int vq_num = 0;
@@ -2926,6 +2927,7 @@ vhost_user_lock_all_queue_pairs(struct virtio_net *dev)
 
 static void
 vhost_user_unlock_all_queue_pairs(struct virtio_net *dev)
+	__rte_no_thread_safety_analysis
 {
 	unsigned int i = 0;
 	unsigned int vq_num = 0;
diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index 5f432b0d77..a8b91d4b20 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -1246,6 +1246,7 @@ vhost_enqueue_single_packed(struct virtio_net *dev,
 static __rte_noinline uint32_t
 virtio_dev_rx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	struct rte_mbuf **pkts, uint32_t count)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
 	uint32_t pkt_idx = 0;
 	uint16_t num_buffers;
@@ -1441,6 +1442,7 @@ virtio_dev_rx_packed(struct virtio_net *dev,
 		     struct vhost_virtqueue *__rte_restrict vq,
 		     struct rte_mbuf **__rte_restrict pkts,
 		     uint32_t count)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
 	uint32_t pkt_idx = 0;
 
@@ -1955,11 +1957,11 @@ write_back_completed_descs_packed(struct vhost_virtqueue *vq,
 }
 
 static __rte_always_inline uint16_t
-vhost_poll_enqueue_completed(struct virtio_net *dev, uint16_t queue_id,
+vhost_poll_enqueue_completed(struct virtio_net *dev, struct vhost_virtqueue *vq,
 		struct rte_mbuf **pkts, uint16_t count, int16_t dma_id,
 		uint16_t vchan_id)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
-	struct vhost_virtqueue *vq = dev->virtqueue[queue_id];
 	struct vhost_async *async = vq->async;
 	struct async_inflight_info *pkts_info = async->pkts_info;
 	uint16_t nr_cpl_pkts = 0;
@@ -2062,7 +2064,7 @@ rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
 		goto out;
 	}
 
-	n_pkts_cpl = vhost_poll_enqueue_completed(dev, queue_id, pkts, count, dma_id, vchan_id);
+	n_pkts_cpl = vhost_poll_enqueue_completed(dev, vq, pkts, count, dma_id, vchan_id);
 
 out:
 	rte_spinlock_unlock(&vq->access_lock);
@@ -2104,7 +2106,7 @@ rte_vhost_clear_queue_thread_unsafe(int vid, uint16_t queue_id,
 		return 0;
 	}
 
-	n_pkts_cpl = vhost_poll_enqueue_completed(dev, queue_id, pkts, count, dma_id, vchan_id);
+	n_pkts_cpl = vhost_poll_enqueue_completed(dev, vq, pkts, count, dma_id, vchan_id);
 
 	return n_pkts_cpl;
 }
@@ -2679,6 +2681,7 @@ static uint16_t
 virtio_dev_tx_split(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count,
 	bool legacy_ol_flags)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
 	uint16_t i;
 	uint16_t free_entries;
@@ -2774,6 +2777,7 @@ static uint16_t
 virtio_dev_tx_split_legacy(struct virtio_net *dev,
 	struct vhost_virtqueue *vq, struct rte_mempool *mbuf_pool,
 	struct rte_mbuf **pkts, uint16_t count)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
 	return virtio_dev_tx_split(dev, vq, mbuf_pool, pkts, count, true);
 }
@@ -2783,6 +2787,7 @@ static uint16_t
 virtio_dev_tx_split_compliant(struct virtio_net *dev,
 	struct vhost_virtqueue *vq, struct rte_mempool *mbuf_pool,
 	struct rte_mbuf **pkts, uint16_t count)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
 	return virtio_dev_tx_split(dev, vq, mbuf_pool, pkts, count, false);
 }
@@ -2982,6 +2987,7 @@ virtio_dev_tx_packed(struct virtio_net *dev,
 		     struct rte_mbuf **__rte_restrict pkts,
 		     uint32_t count,
 		     bool legacy_ol_flags)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
 	uint32_t pkt_idx = 0;
 
@@ -3025,6 +3031,7 @@ static uint16_t
 virtio_dev_tx_packed_legacy(struct virtio_net *dev,
 	struct vhost_virtqueue *__rte_restrict vq, struct rte_mempool *mbuf_pool,
 	struct rte_mbuf **__rte_restrict pkts, uint32_t count)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
 	return virtio_dev_tx_packed(dev, vq, mbuf_pool, pkts, count, true);
 }
@@ -3034,6 +3041,7 @@ static uint16_t
 virtio_dev_tx_packed_compliant(struct virtio_net *dev,
 	struct vhost_virtqueue *__rte_restrict vq, struct rte_mempool *mbuf_pool,
 	struct rte_mbuf **__rte_restrict pkts, uint32_t count)
+	__rte_exclusive_locks_required(vq->access_lock)
 {
 	return virtio_dev_tx_packed(dev, vq, mbuf_pool, pkts, count, false);
 }
-- 
2.23.0