diff mbox series

[2/4] net/smc: Add netlink net namespace support

Message ID 20211228130611.19124-3-tonylu@linux.alibaba.com (mailing list archive)
State Not Applicable
Headers show
Series RDMA device net namespace support for SMC | expand

Commit Message

Tony Lu Dec. 28, 2021, 1:06 p.m. UTC
This adds net namespace ID to diag of linkgroup, helps us to distinguish
different namespaces, and net_cookie is unique in the whole system.

Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
---
 include/uapi/linux/smc.h      |  2 ++
 include/uapi/linux/smc_diag.h | 11 ++++++-----
 net/smc/smc_core.c            |  3 +++
 net/smc/smc_diag.c            | 16 +++++++++-------
 4 files changed, 20 insertions(+), 12 deletions(-)

Comments

Dmitry V. Levin Jan. 31, 2022, 12:24 a.m. UTC | #1
On Tue, Dec 28, 2021 at 09:06:10PM +0800, Tony Lu wrote:
> This adds net namespace ID to diag of linkgroup, helps us to distinguish
> different namespaces, and net_cookie is unique in the whole system.
> 
> Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
> ---
>  include/uapi/linux/smc.h      |  2 ++
>  include/uapi/linux/smc_diag.h | 11 ++++++-----
>  net/smc/smc_core.c            |  3 +++
>  net/smc/smc_diag.c            | 16 +++++++++-------
>  4 files changed, 20 insertions(+), 12 deletions(-)
> 
> diff --git a/include/uapi/linux/smc.h b/include/uapi/linux/smc.h
> index 20f33b27787f..6c2874fd2c00 100644
> --- a/include/uapi/linux/smc.h
> +++ b/include/uapi/linux/smc.h
> @@ -119,6 +119,8 @@ enum {
>  	SMC_NLA_LGR_R_CONNS_NUM,	/* u32 */
>  	SMC_NLA_LGR_R_V2_COMMON,	/* nest */
>  	SMC_NLA_LGR_R_V2,		/* nest */
> +	SMC_NLA_LGR_R_NET_COOKIE,	/* u64 */
> +	SMC_NLA_LGR_R_PAD,		/* flag */
>  	__SMC_NLA_LGR_R_MAX,
>  	SMC_NLA_LGR_R_MAX = __SMC_NLA_LGR_R_MAX - 1
>  };
> diff --git a/include/uapi/linux/smc_diag.h b/include/uapi/linux/smc_diag.h
> index 8cb3a6fef553..c7008d87f1a4 100644
> --- a/include/uapi/linux/smc_diag.h
> +++ b/include/uapi/linux/smc_diag.h
> @@ -84,11 +84,12 @@ struct smc_diag_conninfo {
>  /* SMC_DIAG_LINKINFO */
>  
>  struct smc_diag_linkinfo {
> -	__u8 link_id;			/* link identifier */
> -	__u8 ibname[IB_DEVICE_NAME_MAX]; /* name of the RDMA device */
> -	__u8 ibport;			/* RDMA device port number */
> -	__u8 gid[40];			/* local GID */
> -	__u8 peer_gid[40];		/* peer GID */
> +	__u8		link_id;		    /* link identifier */
> +	__u8		ibname[IB_DEVICE_NAME_MAX]; /* name of the RDMA device */
> +	__u8		ibport;			    /* RDMA device port number */
> +	__u8		gid[40];		    /* local GID */
> +	__u8		peer_gid[40];		    /* peer GID */
> +	__aligned_u64	net_cookie;                 /* RDMA device net namespace */
>  };
>  
>  struct smc_diag_lgrinfo {

I'm sorry but this is an ABI regression.

Since struct smc_diag_lgrinfo contains an object of type "struct smc_diag_linkinfo",
offset of all subsequent members of struct smc_diag_lgrinfo is changed by
this patch.

As result, applications compiled with the old version of struct smc_diag_linkinfo
will receive garbage in struct smc_diag_lgrinfo.role if the kernel implements
this new version of struct smc_diag_linkinfo.
Karsten Graul Jan. 31, 2022, 1:49 p.m. UTC | #2
On 31/01/2022 01:24, Dmitry V. Levin wrote:
> On Tue, Dec 28, 2021 at 09:06:10PM +0800, Tony Lu wrote:
>> This adds net namespace ID to diag of linkgroup, helps us to distinguish
>> different namespaces, and net_cookie is unique in the whole system.
>>
> 
> I'm sorry but this is an ABI regression.
> 
> Since struct smc_diag_lgrinfo contains an object of type "struct smc_diag_linkinfo",
> offset of all subsequent members of struct smc_diag_lgrinfo is changed by
> this patch.
> 
> As result, applications compiled with the old version of struct smc_diag_linkinfo
> will receive garbage in struct smc_diag_lgrinfo.role if the kernel implements
> this new version of struct smc_diag_linkinfo.
> 

Good catch! This patch adds 2 ways to provide the net_cookie to user space, one is over the new
netlink interface, and the other is using the old smc_diag way. 
Imho to use the new netlink interface is good enough, there is no need to touch the smc_diag ABI.
We already started adding new fields to the netlink interface only, this flexibility is 
the reason why we added this interface initially.

So a patch that removes
	__aligned_u64	net_cookie;
and
	.lnk[0].net_cookie = net->net_cookie,
should solve the issue. 

Thoughts?
diff mbox series

Patch

diff --git a/include/uapi/linux/smc.h b/include/uapi/linux/smc.h
index 20f33b27787f..6c2874fd2c00 100644
--- a/include/uapi/linux/smc.h
+++ b/include/uapi/linux/smc.h
@@ -119,6 +119,8 @@  enum {
 	SMC_NLA_LGR_R_CONNS_NUM,	/* u32 */
 	SMC_NLA_LGR_R_V2_COMMON,	/* nest */
 	SMC_NLA_LGR_R_V2,		/* nest */
+	SMC_NLA_LGR_R_NET_COOKIE,	/* u64 */
+	SMC_NLA_LGR_R_PAD,		/* flag */
 	__SMC_NLA_LGR_R_MAX,
 	SMC_NLA_LGR_R_MAX = __SMC_NLA_LGR_R_MAX - 1
 };
diff --git a/include/uapi/linux/smc_diag.h b/include/uapi/linux/smc_diag.h
index 8cb3a6fef553..c7008d87f1a4 100644
--- a/include/uapi/linux/smc_diag.h
+++ b/include/uapi/linux/smc_diag.h
@@ -84,11 +84,12 @@  struct smc_diag_conninfo {
 /* SMC_DIAG_LINKINFO */
 
 struct smc_diag_linkinfo {
-	__u8 link_id;			/* link identifier */
-	__u8 ibname[IB_DEVICE_NAME_MAX]; /* name of the RDMA device */
-	__u8 ibport;			/* RDMA device port number */
-	__u8 gid[40];			/* local GID */
-	__u8 peer_gid[40];		/* peer GID */
+	__u8		link_id;		    /* link identifier */
+	__u8		ibname[IB_DEVICE_NAME_MAX]; /* name of the RDMA device */
+	__u8		ibport;			    /* RDMA device port number */
+	__u8		gid[40];		    /* local GID */
+	__u8		peer_gid[40];		    /* peer GID */
+	__aligned_u64	net_cookie;                 /* RDMA device net namespace */
 };
 
 struct smc_diag_lgrinfo {
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 05c11bbe4318..b9d6148d1287 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -348,6 +348,9 @@  static int smc_nl_fill_lgr(struct smc_link_group *lgr,
 		goto errattr;
 	if (nla_put_u8(skb, SMC_NLA_LGR_R_VLAN_ID, lgr->vlan_id))
 		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_LGR_R_NET_COOKIE,
+			      lgr->net->net_cookie, SMC_NLA_LGR_R_PAD))
+		goto errattr;
 	memcpy(smc_target, lgr->pnet_id, SMC_MAX_PNETID_LEN);
 	smc_target[SMC_MAX_PNETID_LEN] = 0;
 	if (nla_put_string(skb, SMC_NLA_LGR_R_PNETID, smc_target))
diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c
index c952986a6aca..7c8dad28c18d 100644
--- a/net/smc/smc_diag.c
+++ b/net/smc/smc_diag.c
@@ -145,19 +145,21 @@  static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb,
 	if (smc->conn.lgr && !smc->conn.lgr->is_smcd &&
 	    (req->diag_ext & (1 << (SMC_DIAG_LGRINFO - 1))) &&
 	    !list_empty(&smc->conn.lgr->list)) {
+		struct smc_link *link = smc->conn.lnk;
+		struct net *net = read_pnet(&link->smcibdev->ibdev->coredev.rdma_net);
+
 		struct smc_diag_lgrinfo linfo = {
 			.role = smc->conn.lgr->role,
-			.lnk[0].ibport = smc->conn.lnk->ibport,
-			.lnk[0].link_id = smc->conn.lnk->link_id,
+			.lnk[0].ibport = link->ibport,
+			.lnk[0].link_id = link->link_id,
+			.lnk[0].net_cookie = net->net_cookie,
 		};
 
 		memcpy(linfo.lnk[0].ibname,
 		       smc->conn.lgr->lnk[0].smcibdev->ibdev->name,
-		       sizeof(smc->conn.lnk->smcibdev->ibdev->name));
-		smc_gid_be16_convert(linfo.lnk[0].gid,
-				     smc->conn.lnk->gid);
-		smc_gid_be16_convert(linfo.lnk[0].peer_gid,
-				     smc->conn.lnk->peer_gid);
+		       sizeof(link->smcibdev->ibdev->name));
+		smc_gid_be16_convert(linfo.lnk[0].gid, link->gid);
+		smc_gid_be16_convert(linfo.lnk[0].peer_gid, link->peer_gid);
 
 		if (nla_put(skb, SMC_DIAG_LGRINFO, sizeof(linfo), &linfo) < 0)
 			goto errout;