net/smc: add sysctl for max links per lgr for SMC-R v2.1

Add a new sysctl: net.smc.smcr_max_links_per_lgr, which is
used to control the preferred max links per lgr for SMC-R
v2.1. The default value of this sysctl is 2, and the acceptable
value ranges from 1 to 2.

Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/smc-sysctl.rst b/Documentation/networking/smc-sysctl.rst
index 769149d98773a28f6634b7a8ced908fdd5e2e3c3..c6ef86ef4c4f5d386465dfddebe332e66a5aee95 100644 (file)
--- a/Documentation/networking/smc-sysctl.rst
+++ b/Documentation/networking/smc-sysctl.rst
@@ -57,3 +57,11 @@ rmem - INTEGER
        only allowed 512KiB for SMC-R and 1MiB for SMC-D.
 
        Default: 64KiB
+
+smcr_max_links_per_lgr - INTEGER
+       Controls the max number of links can be added to a SMC-R link group. Notice that
+       the actual number of the links added to a SMC-R link group depends on the number
+       of RDMA devices exist in the system. The acceptable value ranges from 1 to 2. Only
+       for SMC-R v2.1 and later.
+
+       Default: 2

diff --git a/include/net/netns/smc.h b/include/net/netns/smc.h
index 582212ada3ba7441d34fafdd81ae09dae929e8da..da70235878249d136d63f83fd0cf18519ffe2d3f 100644 (file)
--- a/include/net/netns/smc.h
+++ b/include/net/netns/smc.h
@@ -22,5 +22,6 @@ struct netns_smc {
        int                             sysctl_smcr_testlink_time;
        int                             sysctl_wmem;
        int                             sysctl_rmem;
+       int                             sysctl_max_links_per_lgr;
 };
 #endif

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 2a1388841951e4b6d447ab1f7b2dff4586ad4218..c61666e5beed101dd2b23c19964a2b4736b21bda 100644 (file)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2461,7 +2461,7 @@ static void smc_listen_work(struct work_struct *work)
        if (rc)
                goto out_decl;
 
-       rc = smc_clc_srv_v2x_features_validate(pclc, ini);
+       rc = smc_clc_srv_v2x_features_validate(new_smc, pclc, ini);
        if (rc)
                goto out_decl;
 

diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 8deb46c28f1d55e81e996bd6ae06c1f09e30320b..1f87c8895a276574d78546ab1414889899bb6d41 100644 (file)
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -824,6 +824,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
        struct smc_clc_smcd_gid_chid *gidchids;
        struct smc_clc_msg_proposal_area *pclc;
        struct smc_clc_ipv6_prefix *ipv6_prfx;
+       struct net *net = sock_net(&smc->sk);
        struct smc_clc_v2_extension *v2_ext;
        struct smc_clc_msg_smcd *pclc_smcd;
        struct smc_clc_msg_trail *trl;
@@ -944,7 +945,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
        if (smcr_indicated(ini->smc_type_v2)) {
                memcpy(v2_ext->roce, ini->smcrv2.ib_gid_v2, SMC_GID_SIZE);
                v2_ext->max_conns = SMC_CONN_PER_LGR_PREFER;
-               v2_ext->max_links = SMC_LINKS_PER_LGR_MAX_PREFER;
+               v2_ext->max_links = net->smc.sysctl_max_links_per_lgr;
        }
 
        pclc_base->hdr.length = htons(plen);
@@ -1171,10 +1172,12 @@ int smc_clc_send_accept(struct smc_sock *new_smc, bool srv_first_contact,
        return len > 0 ? 0 : len;
 }
 
-int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
+int smc_clc_srv_v2x_features_validate(struct smc_sock *smc,
+                                     struct smc_clc_msg_proposal *pclc,
                                      struct smc_init_info *ini)
 {
        struct smc_clc_v2_extension *pclc_v2_ext;
+       struct net *net = sock_net(&smc->sk);
 
        ini->max_conns = SMC_CONN_PER_LGR_MAX;
        ini->max_links = SMC_LINKS_ADD_LNK_MAX;
@@ -1192,7 +1195,8 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
                if (ini->max_conns < SMC_CONN_PER_LGR_MIN)
                        return SMC_CLC_DECL_MAXCONNERR;
 
-               ini->max_links = min_t(u8, pclc_v2_ext->max_links, SMC_LINKS_PER_LGR_MAX_PREFER);
+               ini->max_links = min_t(u8, pclc_v2_ext->max_links,
+                                      net->smc.sysctl_max_links_per_lgr);
                if (ini->max_links < SMC_LINKS_ADD_LNK_MIN)
                        return SMC_CLC_DECL_MAXLINKERR;
        }

diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
index c5c8e7db775a7680ef7a375692b504bf243b4900..89b258cedffeaffe5ec02d7670bd914abd6ea3cd 100644 (file)
--- a/net/smc/smc_clc.h
+++ b/net/smc/smc_clc.h
@@ -422,7 +422,8 @@ int smc_clc_send_confirm(struct smc_sock *smc, bool clnt_first_contact,
                         u8 version, u8 *eid, struct smc_init_info *ini);
 int smc_clc_send_accept(struct smc_sock *smc, bool srv_first_contact,
                        u8 version, u8 *negotiated_eid, struct smc_init_info *ini);
-int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
+int smc_clc_srv_v2x_features_validate(struct smc_sock *smc,
+                                     struct smc_clc_msg_proposal *pclc,
                                      struct smc_init_info *ini);
 int smc_clc_clnt_v2x_features_validate(struct smc_clc_first_contact_ext *fce,
                                       struct smc_init_info *ini);

diff --git a/net/smc/smc_sysctl.c b/net/smc/smc_sysctl.c
index 5cbc18c6e62b07d09dc4b99a165287d6ccac4922..3e9bb921e40a7a7b04ce185e60480df336b14436 100644 (file)
--- a/net/smc/smc_sysctl.c
+++ b/net/smc/smc_sysctl.c
@@ -25,6 +25,8 @@ static int max_sndbuf = INT_MAX / 2;
 static int max_rcvbuf = INT_MAX / 2;
 static const int net_smc_wmem_init = (64 * 1024);
 static const int net_smc_rmem_init = (64 * 1024);
+static int links_per_lgr_min = SMC_LINKS_ADD_LNK_MIN;
+static int links_per_lgr_max = SMC_LINKS_ADD_LNK_MAX;
 
 static struct ctl_table smc_table[] = {
        {
@@ -68,6 +70,15 @@ static struct ctl_table smc_table[] = {
                .extra1         = &min_rcvbuf,
                .extra2         = &max_rcvbuf,
        },
+       {
+               .procname       = "smcr_max_links_per_lgr",
+               .data           = &init_net.smc.sysctl_max_links_per_lgr,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = &links_per_lgr_min,
+               .extra2         = &links_per_lgr_max,
+       },
        {  }
 };
 
@@ -97,6 +108,7 @@ int __net_init smc_sysctl_net_init(struct net *net)
        net->smc.sysctl_smcr_testlink_time = SMC_LLC_TESTLINK_DEFAULT_TIME;
        WRITE_ONCE(net->smc.sysctl_wmem, net_smc_wmem_init);
        WRITE_ONCE(net->smc.sysctl_rmem, net_smc_rmem_init);
+       net->smc.sysctl_max_links_per_lgr = SMC_LINKS_PER_LGR_MAX_PREFER;
 
        return 0;
 

diff --git a/net/smc/smc_sysctl.h b/net/smc/smc_sysctl.h
index 0becc11bd2f4c0871acb93a725a960069c63d102..5783dd7575dd4a65ccfd38d3e8c8b9a3dc93f81b 100644 (file)
--- a/net/smc/smc_sysctl.h
+++ b/net/smc/smc_sysctl.h
@@ -23,6 +23,7 @@ void __net_exit smc_sysctl_net_exit(struct net *net);
 static inline int smc_sysctl_net_init(struct net *net)
 {
        net->smc.sysctl_autocorking_size = SMC_AUTOCORKING_DEFAULT_SIZE;
+       net->smc.sysctl_max_links_per_lgr = SMC_LINKS_PER_LGR_MAX_PREFER;
        return 0;
 }