net/smc: Add netlink support for SMC fallback statistics

Add support to collect more detailed SMC fallback reason statistics and
provide these statistics to user space on the netlink interface.

Signed-off-by: Guvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/uapi/linux/smc.h b/include/uapi/linux/smc.h
index f32f11b..0f7f87c 100644 (file)
--- a/include/uapi/linux/smc.h
+++ b/include/uapi/linux/smc.h
@@ -48,6 +48,7 @@ enum {
        SMC_NETLINK_GET_DEV_SMCD,
        SMC_NETLINK_GET_DEV_SMCR,
        SMC_NETLINK_GET_STATS,
+       SMC_NETLINK_GET_FBACK_STATS,
 };
 
 /* SMC_GENL_FAMILY top level attributes */
@@ -60,6 +61,7 @@ enum {
        SMC_GEN_DEV_SMCD,               /* nest */
        SMC_GEN_DEV_SMCR,               /* nest */
        SMC_GEN_STATS,                  /* nest */
+       SMC_GEN_FBACK_STATS,            /* nest */
        __SMC_GEN_MAX,
        SMC_GEN_MAX = __SMC_GEN_MAX - 1
 };
@@ -228,4 +230,16 @@ enum {
        __SMC_NLA_STATS_MAX,
        SMC_NLA_STATS_MAX = __SMC_NLA_STATS_MAX - 1
 };
+
+/* SMC_GEN_FBACK_STATS attributes */
+enum {
+       SMC_NLA_FBACK_STATS_PAD,
+       SMC_NLA_FBACK_STATS_TYPE,       /* u8 */
+       SMC_NLA_FBACK_STATS_SRV_CNT,    /* u64 */
+       SMC_NLA_FBACK_STATS_CLNT_CNT,   /* u64 */
+       SMC_NLA_FBACK_STATS_RSN_CODE,   /* u32 */
+       SMC_NLA_FBACK_STATS_RSN_CNT,    /* u16 */
+       __SMC_NLA_FBACK_STATS_MAX,
+       SMC_NLA_FBACK_STATS_MAX = __SMC_NLA_FBACK_STATS_MAX - 1
+};
 #endif /* _UAPI_LINUX_SMC_H */

diff --git a/net/smc/smc_netlink.c b/net/smc/smc_netlink.c
index 30e30b2..6fb6f96 100644 (file)
--- a/net/smc/smc_netlink.c
+++ b/net/smc/smc_netlink.c
@@ -61,6 +61,11 @@ static const struct genl_ops smc_gen_nl_ops[] = {
                /* can be retrieved by unprivileged users */
                .dumpit = smc_nl_get_stats,
        },
+       {
+               .cmd = SMC_NETLINK_GET_FBACK_STATS,
+               /* can be retrieved by unprivileged users */
+               .dumpit = smc_nl_get_fback_stats,
+       },
 };
 
 static const struct nla_policy smc_gen_nl_policy[2] = {

diff --git a/net/smc/smc_netlink.h b/net/smc/smc_netlink.h
index 3477265..5ce2c0a 100644 (file)
--- a/net/smc/smc_netlink.h
+++ b/net/smc/smc_netlink.h
@@ -18,7 +18,7 @@
 extern struct genl_family smc_gen_nl_family;
 
 struct smc_nl_dmp_ctx {
-       int pos[2];
+       int pos[3];
 };
 
 static inline struct smc_nl_dmp_ctx *smc_nl_dmp_ctx(struct netlink_callback *c)

diff --git a/net/smc/smc_stats.c b/net/smc/smc_stats.c
index 72119d3..b3d279d 100644 (file)
--- a/net/smc/smc_stats.c
+++ b/net/smc/smc_stats.c
@@ -312,3 +312,95 @@ errnest:
 errmsg:
        return skb->len;
 }
+
+static int smc_nl_get_fback_details(struct sk_buff *skb,
+                                   struct netlink_callback *cb, int pos,
+                                   bool is_srv)
+{
+       struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
+       int cnt_reported = cb_ctx->pos[2];
+       struct smc_stats_fback *trgt_arr;
+       struct nlattr *attrs;
+       int rc = 0;
+       void *nlh;
+
+       if (is_srv)
+               trgt_arr = &fback_rsn.srv[0];
+       else
+               trgt_arr = &fback_rsn.clnt[0];
+       if (!trgt_arr[pos].fback_code)
+               return -ENODATA;
+       nlh = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+                         &smc_gen_nl_family, NLM_F_MULTI,
+                         SMC_NETLINK_GET_FBACK_STATS);
+       if (!nlh)
+               goto errmsg;
+       attrs = nla_nest_start(skb, SMC_GEN_FBACK_STATS);
+       if (!attrs)
+               goto errout;
+       if (nla_put_u8(skb, SMC_NLA_FBACK_STATS_TYPE, is_srv))
+               goto errattr;
+       if (!cnt_reported) {
+               if (nla_put_u64_64bit(skb, SMC_NLA_FBACK_STATS_SRV_CNT,
+                                     fback_rsn.srv_fback_cnt,
+                                     SMC_NLA_FBACK_STATS_PAD))
+                       goto errattr;
+               if (nla_put_u64_64bit(skb, SMC_NLA_FBACK_STATS_CLNT_CNT,
+                                     fback_rsn.clnt_fback_cnt,
+                                     SMC_NLA_FBACK_STATS_PAD))
+                       goto errattr;
+               cnt_reported = 1;
+       }
+
+       if (nla_put_u32(skb, SMC_NLA_FBACK_STATS_RSN_CODE,
+                       trgt_arr[pos].fback_code))
+               goto errattr;
+       if (nla_put_u16(skb, SMC_NLA_FBACK_STATS_RSN_CNT,
+                       trgt_arr[pos].count))
+               goto errattr;
+
+       cb_ctx->pos[2] = cnt_reported;
+       nla_nest_end(skb, attrs);
+       genlmsg_end(skb, nlh);
+       return rc;
+
+errattr:
+       nla_nest_cancel(skb, attrs);
+errout:
+       genlmsg_cancel(skb, nlh);
+errmsg:
+       return -EMSGSIZE;
+}
+
+int smc_nl_get_fback_stats(struct sk_buff *skb, struct netlink_callback *cb)
+{
+       struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
+       int rc_srv = 0, rc_clnt = 0, k;
+       int skip_serv = cb_ctx->pos[1];
+       int snum = cb_ctx->pos[0];
+       bool is_srv = true;
+
+       mutex_lock(&smc_stat_fback_rsn);
+       for (k = 0; k < SMC_MAX_FBACK_RSN_CNT; k++) {
+               if (k < snum)
+                       continue;
+               if (!skip_serv) {
+                       rc_srv = smc_nl_get_fback_details(skb, cb, k, is_srv);
+                       if (rc_srv && rc_srv != ENODATA)
+                               break;
+               } else {
+                       skip_serv = 0;
+               }
+               rc_clnt = smc_nl_get_fback_details(skb, cb, k, !is_srv);
+               if (rc_clnt && rc_clnt != ENODATA) {
+                       skip_serv = 1;
+                       break;
+               }
+               if (rc_clnt == ENODATA && rc_srv == ENODATA)
+                       break;
+       }
+       mutex_unlock(&smc_stat_fback_rsn);
+       cb_ctx->pos[1] = skip_serv;
+       cb_ctx->pos[0] = k;
+       return skb->len;
+}

diff --git a/net/smc/smc_stats.h b/net/smc/smc_stats.h
index 84baaca..7c35b22 100644 (file)
--- a/net/smc/smc_stats.h
+++ b/net/smc/smc_stats.h
@@ -248,6 +248,7 @@ do { \
 while (0)
 
 int smc_nl_get_stats(struct sk_buff *skb, struct netlink_callback *cb);
+int smc_nl_get_fback_stats(struct sk_buff *skb, struct netlink_callback *cb);
 int smc_stats_init(void) __init;
 void smc_stats_exit(void);