nvmf: Add spdk_nvmf_subsystem_disconnect_host

This will disconnect all connections to a subsystem from a given
host identified by HOSTNQN.

Change-Id: Ibc9cea1f08a58a05dbac3a0bb47df8d8a58e7c10
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/4556
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

include/spdk/nvmf.h

@@ -484,6 +484,25 @@ int spdk_nvmf_subsystem_add_host(struct spdk_nvmf_subsystem *subsystem,
  */
 int spdk_nvmf_subsystem_remove_host(struct spdk_nvmf_subsystem *subsystem, const char *hostnqn);
 
+/**
+ * Disconnect all connections originating from the provided hostnqn
+ *
+ * To disconnect and block all new connections from a host, first call
+ * spdk_nvmf_subsystem_remove_host() to remove it from the list of allowed hosts, then
+ * call spdk_nvmf_subsystem_disconnect_host() to close any remaining connections.
+ *
+ * \param subsystem Subsystem to operate on
+ * \param hostnqn The NQN for the host
+ * \param cb_fn The function to call on completion.
+ * \param cb_arg The argument to pass to the cb_fn.
+ *
+ * \return int. 0 when the asynchronous process starts successfully or a negated errno on failure.
+ */
+int spdk_nvmf_subsystem_disconnect_host(struct spdk_nvmf_subsystem *subsystem,
+					const char *hostnqn,
+					spdk_nvmf_tgt_subsystem_listen_done_fn cb_fn,
+					void *cb_arg);
+
 /**
  * Set whether a subsystem should allow any host or only hosts in the allowed list.
  *

lib/nvmf/spdk_nvmf.map

@@ -31,6 +31,7 @@
 	spdk_nvmf_subsystem_get_next;
 	spdk_nvmf_subsystem_add_host;
 	spdk_nvmf_subsystem_remove_host;
+	spdk_nvmf_subsystem_disconnect_host;
 	spdk_nvmf_subsystem_set_allow_any_host;
 	spdk_nvmf_subsystem_get_allow_any_host;
 	spdk_nvmf_subsystem_host_allowed;

lib/nvmf/subsystem.c

@@ -760,6 +760,79 @@ spdk_nvmf_subsystem_remove_host(struct spdk_nvmf_subsystem *subsystem, const cha
 	return 0;
 }
 
+struct nvmf_subsystem_disconnect_host_ctx {
+	struct spdk_nvmf_subsystem		*subsystem;
+	char					*hostnqn;
+	spdk_nvmf_tgt_subsystem_listen_done_fn	cb_fn;
+	void					*cb_arg;
+};
+
+static void
+nvmf_subsystem_disconnect_host_fini(struct spdk_io_channel_iter *i, int status)
+{
+	struct nvmf_subsystem_disconnect_host_ctx *ctx;
+
+	ctx = spdk_io_channel_iter_get_ctx(i);
+
+	if (ctx->cb_fn) {
+		ctx->cb_fn(ctx->cb_arg, status);
+	}
+	free(ctx->hostnqn);
+	free(ctx);
+}
+
+static void
+nvmf_subsystem_disconnect_qpairs_by_host(struct spdk_io_channel_iter *i)
+{
+	struct nvmf_subsystem_disconnect_host_ctx *ctx;
+	struct spdk_nvmf_poll_group *group;
+	struct spdk_io_channel *ch;
+	struct spdk_nvmf_qpair *qpair, *tmp_qpair;
+	struct spdk_nvmf_ctrlr *ctrlr;
+
+	ctx = spdk_io_channel_iter_get_ctx(i);
+	ch = spdk_io_channel_iter_get_channel(i);
+	group = spdk_io_channel_get_ctx(ch);
+
+	TAILQ_FOREACH_SAFE(qpair, &group->qpairs, link, tmp_qpair) {
+		ctrlr = qpair->ctrlr;
+
+		if (ctrlr == NULL || ctrlr->subsys != ctx->subsystem) {
+			continue;
+		}
+
+		if (strncmp(ctrlr->hostnqn, ctx->hostnqn, sizeof(ctrlr->hostnqn)) == 0) {
+			/* Right now this does not wait for the queue pairs to actually disconnect. */
+			spdk_nvmf_qpair_disconnect(qpair, NULL, NULL);
+		}
+	}
+	spdk_for_each_channel_continue(i, 0);
+}
+
+int
+spdk_nvmf_subsystem_disconnect_host(struct spdk_nvmf_subsystem *subsystem,
+				    const char *hostnqn,
+				    spdk_nvmf_tgt_subsystem_listen_done_fn cb_fn,
+				    void *cb_arg)
+{
+	struct nvmf_subsystem_disconnect_host_ctx *ctx;
+
+	ctx = calloc(1, sizeof(struct nvmf_subsystem_disconnect_host_ctx));
+	if (ctx == NULL) {
+		return -ENOMEM;
+	}
+
+	ctx->subsystem = subsystem;
+	ctx->hostnqn = strdup(hostnqn);
+	ctx->cb_fn = cb_fn;
+	ctx->cb_arg = cb_arg;
+
+	spdk_for_each_channel(subsystem->tgt, nvmf_subsystem_disconnect_qpairs_by_host, ctx,
+			      nvmf_subsystem_disconnect_host_fini);
+
+	return 0;
+}
+
 int
 spdk_nvmf_subsystem_set_allow_any_host(struct spdk_nvmf_subsystem *subsystem, bool allow_any_host)
 {