From: Guvenc Gulce Date: Thu, 10 Sep 2020 18:48:28 +0200 Subject: net/smc: use the retry mechanism for netlink messages Git-commit: 8418cb4065e3d6d214f7d5535c99deba6e813bf7 Patch-mainline: v5.10-rc1 References: jsc#SLE-13763 When the netlink messages to be sent to the userspace are too big for a single netlink message, send them in chunks using the netlink_dump infrastructure. Modify the smc diag dump code so that it can signal to the netlink_dump infrastructure that it needs to send more data. Signed-off-by: Guvenc Gulce Signed-off-by: Karsten Graul Signed-off-by: David S. Miller Acked-by: Petr Tesarik --- net/smc/smc_diag.c | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) --- a/net/smc/smc_diag.c +++ b/net/smc/smc_diag.c @@ -22,6 +22,15 @@ #include "smc.h" #include "smc_core.h" +struct smc_diag_dump_ctx { + int pos[2]; +}; + +static struct smc_diag_dump_ctx *smc_dump_context(struct netlink_callback *cb) +{ + return (struct smc_diag_dump_ctx *)cb->ctx; +} + static void smc_gid_be16_convert(__u8 *buf, u8 *gid_raw) { sprintf(buf, "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x", @@ -193,13 +202,15 @@ errout: } static int smc_diag_dump_proto(struct proto *prot, struct sk_buff *skb, - struct netlink_callback *cb) + struct netlink_callback *cb, int p_type) { + struct smc_diag_dump_ctx *cb_ctx = smc_dump_context(cb); struct net *net = sock_net(skb->sk); + int snum = cb_ctx->pos[p_type]; struct nlattr *bc = NULL; struct hlist_head *head; + int rc = 0, num = 0; struct sock *sk; - int rc = 0; read_lock(&prot->h.smc_hash->lock); head = &prot->h.smc_hash->ht; @@ -209,13 +220,18 @@ static int smc_diag_dump_proto(struct pr sk_for_each(sk, head) { if (!net_eq(sock_net(sk), net)) continue; + if (num < snum) + goto next; rc = __smc_diag_dump(sk, skb, cb, nlmsg_data(cb->nlh), bc); - if (rc) - break; + if (rc < 0) + goto out; +next: + num++; } out: read_unlock(&prot->h.smc_hash->lock); + cb_ctx->pos[p_type] = num; return rc; } @@ -223,10 +239,10 @@ static int smc_diag_dump(struct sk_buff { int rc = 0; - rc = smc_diag_dump_proto(&smc_proto, skb, cb); + rc = smc_diag_dump_proto(&smc_proto, skb, cb, SMCPROTO_SMC); if (!rc) - rc = smc_diag_dump_proto(&smc_proto6, skb, cb); - return rc; + smc_diag_dump_proto(&smc_proto6, skb, cb, SMCPROTO_SMC6); + return skb->len; } static int smc_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h)