[PATCH net-next] sctp: uncork the old asoc before changing to the new one

[PATCH net-next] sctp: uncork the old asoc before changing to the new one

[Xin Long]

local_cork is used to decide if it should uncork asoc outq after processing
some cmds, and it is set when replying or sending msgs. local_cork should
always have the same value with current asoc q->cork in some way.

The thing is when changing to a new asoc by cmd SET_ASOC, local_cork may
not be consistent with the current asoc any more. The cmd seqs can be:

  SCTP_CMD_UPDATE_ASSOC (asoc)
  SCTP_CMD_REPLY (asoc)
  SCTP_CMD_SET_ASOC (new_asoc)
  SCTP_CMD_DELETE_TCB (new_asoc)
  SCTP_CMD_SET_ASOC (asoc)
  SCTP_CMD_REPLY (asoc)

The 1st REPLY makes OLD asoc q->cork and local_cork both are 1, and the cmd
DELETE_TCB clears NEW asoc q->cork and local_cork. After asoc goes back to
OLD asoc, q->cork is still 1 while local_cork is 0. The 2nd REPLY will not
set local_cork because q->cork is already set and it can't be uncorked and
sent out because of this.

To keep local_cork consistent with the current asoc q->cork, this patch is
to uncork the old asoc if local_cork is set before changing to the new one.

Note that the above cmd seqs will be used in the next patch when updating
asoc and handling errors in it.

Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
 net/sctp/sm_sideeffect.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index 25384fa..7623566 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -1748,6 +1748,10 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
 			break;
 
 		case SCTP_CMD_SET_ASOC:
+			if (asoc && local_cork) {
+				sctp_outq_uncork(&asoc->outqueue, gfp);
+				local_cork = 0;
+			}
 			asoc = cmd->obj.asoc;
 			break;
 
-- 
2.1.0

Re: [PATCH net-next] sctp: uncork the old asoc before changing to the new one

[Marcelo Ricardo Leitner]

On Tue, Jun 20, 2017 at 04:01:55PM +0800, Xin Long wrote:
> local_cork is used to decide if it should uncork asoc outq after processing
> some cmds, and it is set when replying or sending msgs. local_cork should
> always have the same value with current asoc q->cork in some way.
> 
> The thing is when changing to a new asoc by cmd SET_ASOC, local_cork may
> not be consistent with the current asoc any more. The cmd seqs can be:
> 
>   SCTP_CMD_UPDATE_ASSOC (asoc)
>   SCTP_CMD_REPLY (asoc)
>   SCTP_CMD_SET_ASOC (new_asoc)
>   SCTP_CMD_DELETE_TCB (new_asoc)
>   SCTP_CMD_SET_ASOC (asoc)
>   SCTP_CMD_REPLY (asoc)
> 
> The 1st REPLY makes OLD asoc q->cork and local_cork both are 1, and the cmd
> DELETE_TCB clears NEW asoc q->cork and local_cork. After asoc goes back to
> OLD asoc, q->cork is still 1 while local_cork is 0. The 2nd REPLY will not
> set local_cork because q->cork is already set and it can't be uncorked and
> sent out because of this.
> 
> To keep local_cork consistent with the current asoc q->cork, this patch is
> to uncork the old asoc if local_cork is set before changing to the new one.
> 
> Note that the above cmd seqs will be used in the next patch when updating
> asoc and handling errors in it.
> 
> Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

> Signed-off-by: Xin Long <lucien.xin@gmail.com>
> ---
>  net/sctp/sm_sideeffect.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
> index 25384fa..7623566 100644
> --- a/net/sctp/sm_sideeffect.c
> +++ b/net/sctp/sm_sideeffect.c
> @@ -1748,6 +1748,10 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
>  			break;
>  
>  		case SCTP_CMD_SET_ASOC:
> +			if (asoc && local_cork) {
> +				sctp_outq_uncork(&asoc->outqueue, gfp);
> +				local_cork = 0;
> +			}
>  			asoc = cmd->obj.asoc;
>  			break;
>  
> -- 
> 2.1.0
> 
> --
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> 

Re: [PATCH net-next] sctp: uncork the old asoc before changing to the new one

[Neil Horman]

On Tue, Jun 20, 2017 at 04:01:55PM +0800, Xin Long wrote:
> local_cork is used to decide if it should uncork asoc outq after processing
> some cmds, and it is set when replying or sending msgs. local_cork should
> always have the same value with current asoc q->cork in some way.
> 
> The thing is when changing to a new asoc by cmd SET_ASOC, local_cork may
> not be consistent with the current asoc any more. The cmd seqs can be:
> 
>   SCTP_CMD_UPDATE_ASSOC (asoc)
>   SCTP_CMD_REPLY (asoc)
>   SCTP_CMD_SET_ASOC (new_asoc)
>   SCTP_CMD_DELETE_TCB (new_asoc)
>   SCTP_CMD_SET_ASOC (asoc)
>   SCTP_CMD_REPLY (asoc)
> 
> The 1st REPLY makes OLD asoc q->cork and local_cork both are 1, and the cmd
> DELETE_TCB clears NEW asoc q->cork and local_cork. After asoc goes back to
> OLD asoc, q->cork is still 1 while local_cork is 0. The 2nd REPLY will not
> set local_cork because q->cork is already set and it can't be uncorked and
> sent out because of this.
> 
> To keep local_cork consistent with the current asoc q->cork, this patch is
> to uncork the old asoc if local_cork is set before changing to the new one.
> 
> Note that the above cmd seqs will be used in the next patch when updating
> asoc and handling errors in it.
> 
> Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> Signed-off-by: Xin Long <lucien.xin@gmail.com>
> ---
>  net/sctp/sm_sideeffect.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
> index 25384fa..7623566 100644
> --- a/net/sctp/sm_sideeffect.c
> +++ b/net/sctp/sm_sideeffect.c
> @@ -1748,6 +1748,10 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
>  			break;
>  
>  		case SCTP_CMD_SET_ASOC:
> +			if (asoc && local_cork) {
> +				sctp_outq_uncork(&asoc->outqueue, gfp);
> +				local_cork = 0;
> +			}
>  			asoc = cmd->obj.asoc;
>  			break;
>  
> -- 
> 2.1.0
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-sctp" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
Acked-by: Neil Horman <nhorman@tuxdriver.com>

Re: [PATCH net-next] sctp: uncork the old asoc before changing to the new one

[David Miller]

From: Xin Long <lucien.xin@gmail.com>
Date: Tue, 20 Jun 2017 16:01:55 +0800

> local_cork is used to decide if it should uncork asoc outq after processing
> some cmds, and it is set when replying or sending msgs. local_cork should
> always have the same value with current asoc q->cork in some way.
> 
> The thing is when changing to a new asoc by cmd SET_ASOC, local_cork may
> not be consistent with the current asoc any more. The cmd seqs can be:
> 
>   SCTP_CMD_UPDATE_ASSOC (asoc)
>   SCTP_CMD_REPLY (asoc)
>   SCTP_CMD_SET_ASOC (new_asoc)
>   SCTP_CMD_DELETE_TCB (new_asoc)
>   SCTP_CMD_SET_ASOC (asoc)
>   SCTP_CMD_REPLY (asoc)
> 
> The 1st REPLY makes OLD asoc q->cork and local_cork both are 1, and the cmd
> DELETE_TCB clears NEW asoc q->cork and local_cork. After asoc goes back to
> OLD asoc, q->cork is still 1 while local_cork is 0. The 2nd REPLY will not
> set local_cork because q->cork is already set and it can't be uncorked and
> sent out because of this.
> 
> To keep local_cork consistent with the current asoc q->cork, this patch is
> to uncork the old asoc if local_cork is set before changing to the new one.
> 
> Note that the above cmd seqs will be used in the next patch when updating
> asoc and handling errors in it.
> 
> Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> Signed-off-by: Xin Long <lucien.xin@gmail.com>

Applied.