diff mbox series

[RFC,v3,5/8] vhost: annotate need reply handling

Message ID 20220411110013.18624-6-david.marchand@redhat.com (mailing list archive)
State Deferred
Delegated to: David Marchand
Headers show
Series vhost lock annotations | expand

Commit Message

David Marchand April 11, 2022, 11 a.m. UTC
When a reply from the slave is required (VHOST_USER_NEED_REPLY flag),
a spinlock is taken before sending the message.
This spinlock is released if an error occurs when sending the message, and
once a reply is received.

A problem is that this lock is taken under a branch and annotating
conditionally held locks is not supported.
The code seems currently correct and, while we may rework the code,
it is easier to simply skip checks on slave_req_lock for those helpers.

Signed-off-by: David Marchand <david.marchand@redhat.com>
---
 lib/vhost/vhost_user.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Maxime Coquelin April 22, 2022, 7:25 a.m. UTC | #1
On 4/11/22 13:00, David Marchand wrote:
> When a reply from the slave is required (VHOST_USER_NEED_REPLY flag),
> a spinlock is taken before sending the message.
> This spinlock is released if an error occurs when sending the message, and
> once a reply is received.
> 
> A problem is that this lock is taken under a branch and annotating
> conditionally held locks is not supported.
> The code seems currently correct and, while we may rework the code,
> it is easier to simply skip checks on slave_req_lock for those helpers.
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
>   lib/vhost/vhost_user.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
> index ee276a28f1..d101d5072f 100644
> --- a/lib/vhost/vhost_user.c
> +++ b/lib/vhost/vhost_user.c
> @@ -2854,6 +2854,7 @@ send_vhost_reply(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx
>   static int
>   send_vhost_slave_message(struct virtio_net *dev,
>   		struct vhu_msg_context *ctx)
> +	__rte_no_thread_safety_analysis
>   {
>   	int ret;
>   
> @@ -3165,6 +3166,7 @@ vhost_user_msg_handler(int vid, int fd)
>   
>   static int process_slave_message_reply(struct virtio_net *dev,
>   				       const struct vhu_msg_context *ctx)
> +	__rte_no_thread_safety_analysis
>   {
>   	struct vhu_msg_context msg_reply;
>   	int ret;

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime
diff mbox series

Patch

diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index ee276a28f1..d101d5072f 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -2854,6 +2854,7 @@  send_vhost_reply(struct virtio_net *dev, int sockfd, struct vhu_msg_context *ctx
 static int
 send_vhost_slave_message(struct virtio_net *dev,
 		struct vhu_msg_context *ctx)
+	__rte_no_thread_safety_analysis
 {
 	int ret;
 
@@ -3165,6 +3166,7 @@  vhost_user_msg_handler(int vid, int fd)
 
 static int process_slave_message_reply(struct virtio_net *dev,
 				       const struct vhu_msg_context *ctx)
+	__rte_no_thread_safety_analysis
 {
 	struct vhu_msg_context msg_reply;
 	int ret;