[ovs-dev] ofproto-dpif-upcall: Transition ukey on dp_ops error.

Message ID 20170906221252.17257-1-joe@ovn.org
State New
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  • [ovs-dev] ofproto-dpif-upcall: Transition ukey on dp_ops error.
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Commit Message

Joe Stringer Sept. 6, 2017, 10:12 p.m.
In most situations, we don't expect that a flow we've successfully
dumped, which we intend to delete, cannot be deleted. However, to make
this code more resilient to ensure that ukeys *will* transition in all
cases (including an error at this stage), grab the lock and transition
this ukey forward to the evicted state, effectively treating a failure
to delete as "this flow is already gone".

If we subsequently find out that it wasn't deleted, then that's ok - we
will re-dump, and validate at that stage, which should lead to creating
a new ukey or deleting the datapath flow when that happens.

Signed-off-by: Joe Stringer <joe@ovn.org>
---
 ofproto/ofproto-dpif-upcall.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Greg Rose Sept. 18, 2017, 9:56 p.m. | #1
On 09/06/2017 03:12 PM, Joe Stringer wrote:
> In most situations, we don't expect that a flow we've successfully
> dumped, which we intend to delete, cannot be deleted. However, to make
> this code more resilient to ensure that ukeys *will* transition in all
> cases (including an error at this stage), grab the lock and transition
> this ukey forward to the evicted state, effectively treating a failure
> to delete as "this flow is already gone".
> 
> If we subsequently find out that it wasn't deleted, then that's ok - we
> will re-dump, and validate at that stage, which should lead to creating
> a new ukey or deleting the datapath flow when that happens.
> 
> Signed-off-by: Joe Stringer <joe@ovn.org>
> ---
>   ofproto/ofproto-dpif-upcall.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c
> index 4a71bbe258df..bd324fbb6323 100644
> --- a/ofproto/ofproto-dpif-upcall.c
> +++ b/ofproto/ofproto-dpif-upcall.c
> @@ -2227,6 +2227,11 @@ push_dp_ops(struct udpif *udpif, struct ukey_op *ops, size_t n_ops)
>   
>           if (op->dop.error) {
>               /* flow_del error, 'stats' is unusable. */
> +            if (op->ukey) {
> +                ovs_mutex_lock(&op->ukey->mutex);
> +                transition_ukey(op->ukey, UKEY_EVICTED);
> +                ovs_mutex_unlock(&op->ukey->mutex);
> +            }
>               continue;
>           }
>   
> 

Compile tested only - I didn't see of any good way to force the error

Code looks good to me.

Reviewed-by: Greg Rose <gvrose8192@gmail.com>

Patch

diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c
index 4a71bbe258df..bd324fbb6323 100644
--- a/ofproto/ofproto-dpif-upcall.c
+++ b/ofproto/ofproto-dpif-upcall.c
@@ -2227,6 +2227,11 @@  push_dp_ops(struct udpif *udpif, struct ukey_op *ops, size_t n_ops)
 
         if (op->dop.error) {
             /* flow_del error, 'stats' is unusable. */
+            if (op->ukey) {
+                ovs_mutex_lock(&op->ukey->mutex);
+                transition_ukey(op->ukey, UKEY_EVICTED);
+                ovs_mutex_unlock(&op->ukey->mutex);
+            }
             continue;
         }