smc_sysctl.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 *  Shared Memory Communications over RDMA (SMC-R) and RoCE
  4 *
  5 *  smc_sysctl.c: sysctl interface to SMC subsystem.
  6 *
  7 *  Copyright (c) 2022, Alibaba Inc.
  8 *
  9 *  Author: Tony Lu <tonylu@linux.alibaba.com>
 10 *
 11 */
 12
 13#include <linux/init.h>
 14#include <linux/sysctl.h>
 15#include <linux/bpf.h>
 16#include <net/net_namespace.h>
 17
 18#include "smc.h"
 19#include "smc_core.h"
 20#include "smc_llc.h"
 21#include "smc_sysctl.h"
 22#include "smc_hs_bpf.h"
 23
 24static int min_sndbuf = SMC_BUF_MIN_SIZE;
 25static int min_rcvbuf = SMC_BUF_MIN_SIZE;
 26static int max_sndbuf = INT_MAX / 2;
 27static int max_rcvbuf = INT_MAX / 2;
 28static const int net_smc_wmem_init = (64 * 1024);
 29static const int net_smc_rmem_init = (64 * 1024);
 30static int links_per_lgr_min = SMC_LINKS_ADD_LNK_MIN;
 31static int links_per_lgr_max = SMC_LINKS_ADD_LNK_MAX;
 32static int conns_per_lgr_min = SMC_CONN_PER_LGR_MIN;
 33static int conns_per_lgr_max = SMC_CONN_PER_LGR_MAX;
 34static unsigned int smcr_max_wr_min = 2;
 35static unsigned int smcr_max_wr_max = 2048;
 36
 37#if IS_ENABLED(CONFIG_SMC_HS_CTRL_BPF)
 38static int smc_net_replace_smc_hs_ctrl(struct net *net, const char *name)
 39{
 40	struct smc_hs_ctrl *ctrl = NULL;
 41
 42	rcu_read_lock();
 43	/* null or empty name ask to clear current ctrl */
 44	if (name && name[0]) {
 45		ctrl = smc_hs_ctrl_find_by_name(name);
 46		if (!ctrl) {
 47			rcu_read_unlock();
 48			return -EINVAL;
 49		}
 50		/* no change, just return */
 51		if (ctrl == rcu_dereference(net->smc.hs_ctrl)) {
 52			rcu_read_unlock();
 53			return 0;
 54		}
 55		if (!bpf_try_module_get(ctrl, ctrl->owner)) {
 56			rcu_read_unlock();
 57			return -EBUSY;
 58		}
 59	}
 60	/* xhcg old ctrl with the new one atomically */
 61	ctrl = unrcu_pointer(xchg(&net->smc.hs_ctrl, RCU_INITIALIZER(ctrl)));
 62	/* release old ctrl */
 63	if (ctrl)
 64		bpf_module_put(ctrl, ctrl->owner);
 65
 66	rcu_read_unlock();
 67	return 0;
 68}
 69
 70static int proc_smc_hs_ctrl(const struct ctl_table *ctl, int write,
 71			    void *buffer, size_t *lenp, loff_t *ppos)
 72{
 73	struct net *net = container_of(ctl->data, struct net, smc.hs_ctrl);
 74	char val[SMC_HS_CTRL_NAME_MAX];
 75	const struct ctl_table tbl = {
 76		.data = val,
 77		.maxlen = SMC_HS_CTRL_NAME_MAX,
 78	};
 79	struct smc_hs_ctrl *ctrl;
 80	int ret;
 81
 82	rcu_read_lock();
 83	ctrl = rcu_dereference(net->smc.hs_ctrl);
 84	if (ctrl)
 85		memcpy(val, ctrl->name, sizeof(ctrl->name));
 86	else
 87		val[0] = '\0';
 88	rcu_read_unlock();
 89
 90	ret = proc_dostring(&tbl, write, buffer, lenp, ppos);
 91	if (ret)
 92		return ret;
 93
 94	if (write)
 95		ret = smc_net_replace_smc_hs_ctrl(net, val);
 96	return ret;
 97}
 98#endif /* CONFIG_SMC_HS_CTRL_BPF */
 99
100static struct ctl_table smc_table[] = {
101	{
102		.procname       = "autocorking_size",
103		.data           = &init_net.smc.sysctl_autocorking_size,
104		.maxlen         = sizeof(unsigned int),
105		.mode           = 0644,
106		.proc_handler	= proc_douintvec,
107	},
108	{
109		.procname	= "smcr_buf_type",
110		.data		= &init_net.smc.sysctl_smcr_buf_type,
111		.maxlen		= sizeof(unsigned int),
112		.mode		= 0644,
113		.proc_handler	= proc_douintvec_minmax,
114		.extra1		= SYSCTL_ZERO,
115		.extra2		= SYSCTL_TWO,
116	},
117	{
118		.procname	= "smcr_testlink_time",
119		.data		= &init_net.smc.sysctl_smcr_testlink_time,
120		.maxlen		= sizeof(int),
121		.mode		= 0644,
122		.proc_handler	= proc_dointvec_jiffies,
123	},
124	{
125		.procname	= "wmem",
126		.data		= &init_net.smc.sysctl_wmem,
127		.maxlen		= sizeof(int),
128		.mode		= 0644,
129		.proc_handler	= proc_dointvec_minmax,
130		.extra1		= &min_sndbuf,
131		.extra2		= &max_sndbuf,
132	},
133	{
134		.procname	= "rmem",
135		.data		= &init_net.smc.sysctl_rmem,
136		.maxlen		= sizeof(int),
137		.mode		= 0644,
138		.proc_handler	= proc_dointvec_minmax,
139		.extra1		= &min_rcvbuf,
140		.extra2		= &max_rcvbuf,
141	},
142	{
143		.procname	= "smcr_max_links_per_lgr",
144		.data		= &init_net.smc.sysctl_max_links_per_lgr,
145		.maxlen		= sizeof(int),
146		.mode		= 0644,
147		.proc_handler	= proc_dointvec_minmax,
148		.extra1		= &links_per_lgr_min,
149		.extra2		= &links_per_lgr_max,
150	},
151	{
152		.procname	= "smcr_max_conns_per_lgr",
153		.data		= &init_net.smc.sysctl_max_conns_per_lgr,
154		.maxlen		= sizeof(int),
155		.mode		= 0644,
156		.proc_handler	= proc_dointvec_minmax,
157		.extra1		= &conns_per_lgr_min,
158		.extra2		= &conns_per_lgr_max,
159	},
160	{
161		.procname	= "limit_smc_hs",
162		.data		= &init_net.smc.limit_smc_hs,
163		.maxlen		= sizeof(int),
164		.mode		= 0644,
165		.proc_handler	= proc_dointvec_minmax,
166		.extra1		= SYSCTL_ZERO,
167		.extra2		= SYSCTL_ONE,
168	},
169	{
170		.procname	= "smcr_max_send_wr",
171		.data		= &init_net.smc.sysctl_smcr_max_send_wr,
172		.maxlen		= sizeof(int),
173		.mode		= 0644,
174		.proc_handler	= proc_dointvec_minmax,
175		.extra1		= &smcr_max_wr_min,
176		.extra2		= &smcr_max_wr_max,
177	},
178	{
179		.procname	= "smcr_max_recv_wr",
180		.data		= &init_net.smc.sysctl_smcr_max_recv_wr,
181		.maxlen		= sizeof(int),
182		.mode		= 0644,
183		.proc_handler	= proc_dointvec_minmax,
184		.extra1		= &smcr_max_wr_min,
185		.extra2		= &smcr_max_wr_max,
186	},
187#if IS_ENABLED(CONFIG_SMC_HS_CTRL_BPF)
188	{
189		.procname	= "hs_ctrl",
190		.data		= &init_net.smc.hs_ctrl,
191		.mode		= 0644,
192		.maxlen		= SMC_HS_CTRL_NAME_MAX,
193		.proc_handler	= proc_smc_hs_ctrl,
194	},
195#endif /* CONFIG_SMC_HS_CTRL_BPF */
196};
197
198int __net_init smc_sysctl_net_init(struct net *net)
199{
200	size_t table_size = ARRAY_SIZE(smc_table);
201	struct ctl_table *table;
202
203	table = smc_table;
204	if (!net_eq(net, &init_net)) {
205		int i;
206#if IS_ENABLED(CONFIG_SMC_HS_CTRL_BPF)
207		struct smc_hs_ctrl *ctrl;
208
209		rcu_read_lock();
210		ctrl = rcu_dereference(init_net.smc.hs_ctrl);
211		if (ctrl && ctrl->flags & SMC_HS_CTRL_FLAG_INHERITABLE &&
212		    bpf_try_module_get(ctrl, ctrl->owner))
213			rcu_assign_pointer(net->smc.hs_ctrl, ctrl);
214		rcu_read_unlock();
215#endif /* CONFIG_SMC_HS_CTRL_BPF */
216
217		table = kmemdup(table, sizeof(smc_table), GFP_KERNEL);
218		if (!table)
219			goto err_alloc;
220
221		for (i = 0; i < table_size; i++)
222			table[i].data += (void *)net - (void *)&init_net;
223	}
224
225	net->smc.smc_hdr = register_net_sysctl_sz(net, "net/smc", table,
226						  table_size);
227	if (!net->smc.smc_hdr)
228		goto err_reg;
229
230	net->smc.sysctl_autocorking_size = SMC_AUTOCORKING_DEFAULT_SIZE;
231	net->smc.sysctl_smcr_buf_type = SMCR_PHYS_CONT_BUFS;
232	net->smc.sysctl_smcr_testlink_time = SMC_LLC_TESTLINK_DEFAULT_TIME;
233	WRITE_ONCE(net->smc.sysctl_wmem, net_smc_wmem_init);
234	WRITE_ONCE(net->smc.sysctl_rmem, net_smc_rmem_init);
235	net->smc.sysctl_max_links_per_lgr = SMC_LINKS_PER_LGR_MAX_PREFER;
236	net->smc.sysctl_max_conns_per_lgr = SMC_CONN_PER_LGR_PREFER;
237	net->smc.sysctl_smcr_max_send_wr = SMCR_MAX_SEND_WR_DEF;
238	net->smc.sysctl_smcr_max_recv_wr = SMCR_MAX_RECV_WR_DEF;
239	/* disable handshake limitation by default */
240	net->smc.limit_smc_hs = 0;
241
242	return 0;
243
244err_reg:
245	if (!net_eq(net, &init_net))
246		kfree(table);
247err_alloc:
248#if IS_ENABLED(CONFIG_SMC_HS_CTRL_BPF)
249	smc_net_replace_smc_hs_ctrl(net, NULL);
250#endif /* CONFIG_SMC_HS_CTRL_BPF */
251	return -ENOMEM;
252}
253
254void __net_exit smc_sysctl_net_exit(struct net *net)
255{
256	const struct ctl_table *table;
257
258	table = net->smc.smc_hdr->ctl_table_arg;
259	unregister_net_sysctl_table(net->smc.smc_hdr);
260#if IS_ENABLED(CONFIG_SMC_HS_CTRL_BPF)
261	smc_net_replace_smc_hs_ctrl(net, NULL);
262#endif /* CONFIG_SMC_HS_CTRL_BPF */
263
264	if (!net_eq(net, &init_net))
265		kfree(table);
266}