[PATCH] librdmacm/doc: document the limitations on the user provided private data length

[PATCH] librdmacm/doc: document the limitations on the user provided private data length

[Or Gerlitz]

Document the limitations on the user provided private data length
over Infiniband networks. These limitations are calculated by
subtracting the rdma-cm header size (see IBA Annex A11 "RDMA CM IP
Service") from IB's private data len for the REQ (rdma_connect) and
REP (rdma_accept) messages

Signed-off-by: Or Gerlitz <ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>

 man/rdma_accept.3  |    2 ++
 man/rdma_connect.3 |    2 ++
 2 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/man/rdma_accept.3 b/man/rdma_accept.3
index ac04e2c..0a9415a 100644
--- a/man/rdma_accept.3
+++ b/man/rdma_accept.3
@@ -84,5 +84,7 @@ by the active side of the connection.  The HCA ACK delay is a property of
 the locally used HCA.
 .P
 The RNR retry count is a 3-bit value.
+.P
+The length of the private data provided by the user is limited to 160 bytes.
 .SH "SEE ALSO"
 rdma_listen(3), rdma_reject(3), rdma_get_cm_event(3)
diff --git a/man/rdma_connect.3 b/man/rdma_connect.3
index b0cc51e..8035d47 100644
--- a/man/rdma_connect.3
+++ b/man/rdma_connect.3
@@ -79,6 +79,8 @@ Administrator and is part of the resolved route (path record) information.
 The HCA ACK delay is a property of the locally used HCA.
 .P
 Retry count and RNR retry count values are 3-bit values.
+.P
+The length of the private data provided by the user is limited to 56 bytes.
 .SH "IWARP SPECIFIC"
 Connections established over iWarp RDMA devices currently require that the
 active side of the connection send the first message.
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RE: [PATCH] librdmacm/doc: document the limitations on the user provided private data length

[Hefty, Sean]

Thanks - I modified the patch to further specify the difference between RC and UD:

> diff --git a/man/rdma_accept.3 b/man/rdma_accept.3
> index ac04e2c..0a9415a 100644
> --- a/man/rdma_accept.3
> +++ b/man/rdma_accept.3
> @@ -84,5 +84,7 @@ by the active side of the connection.  The HCA ACK delay is a property of
>  the locally used HCA.
>  .P
>  The RNR retry count is a 3-bit value.
> +.P
> +The length of the private data provided by the user is limited to 160 bytes

+ for RDMA_PS_TCP, or 136 bytes for RDMA_PS_UDP.

>  .SH "SEE ALSO"
>  rdma_listen(3), rdma_reject(3), rdma_get_cm_event(3)
> diff --git a/man/rdma_connect.3 b/man/rdma_connect.3
> index b0cc51e..8035d47 100644
> --- a/man/rdma_connect.3
> +++ b/man/rdma_connect.3
> @@ -79,6 +79,8 @@ Administrator and is part of the resolved route (path record) information.
>  The HCA ACK delay is a property of the locally used HCA.
>  .P
>  Retry count and RNR retry count values are 3-bit values.
> +.P
> +The length of the private data provided by the user is limited to 56 bytes

+ for RDMA_PS_TCP, or 180 bytes for RDMA_PS_UDP.

- Sean
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Re: [PATCH] librdmacm/doc: document the limitations on the user provided private data length

[Or Gerlitz]

Hefty, Sean wrote:
> I modified the patch to further specify the difference between RC and UD:

I don't see it on your librdmacm git tree, assuming it on a local clone 
which you will sync with the public one soon?

Or.
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RE: [PATCH] librdmacm/doc: document the limitations on the user provided private data length

[Hefty, Sean]

> I don't see it on your librdmacm git tree, assuming it on a local clone
> which you will sync with the public one soon?

changes have been pushed
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Re: [PATCH] librdmacm/doc: document the limitations on the user provided private data length

[Yann Droneaud]

Le lundi 28 mars 2011 à 10:49 +0200, Or Gerlitz a écrit :
> Document the limitations on the user provided private data length
> over Infiniband networks. These limitations are calculated by
> subtracting the rdma-cm header size (see IBA Annex A11 "RDMA CM IP
> Service") from IB's private data len for the REQ (rdma_connect) and
> REP (rdma_accept) messages

In Annex A11 "RMDA CM IP Service" of Infiniband Architecture Release
1.2.1 (November 2007), there's nothing about the REP messages. Only REQ
(table 532) messages are specified in this section.

For general REP messages, one have to look to table 103 : "REP Message
Contents" in section 12.6.8 REP - Reply to Request For Communication.

Am I correct ?

Regards.

-- 
Yann Droneaud
OPTEYA


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RE: [PATCH] librdmacm/doc: document the limitations on the user provided private data length

[Hefty, Sean]

> For general REP messages, one have to look to table 103 : "REP Message
> Contents" in section 12.6.8 REP - Reply to Request For Communication.
> 
> Am I correct ?

I believe so.  The rdma_accept size should be 196 for RDMA_PS_TCP.