[rdma-next v2 02/33] RDMA/netlink: Remove netlink clients infrastructure

Leon Romanovsky
2017-08-10T11:07:56Z

RDMA netlink has a complicated infrastructure for dynamically
registering and de-registering netlink clients to the NETLINK_RDMA
group. The complicated portion of this code is not widely used because
2 of the 3 current clients are statically compiled together with
netlink.c. The infrastructure, therefore, is deemed overkill.

Refactor the code to eliminate the dynamically added clients. Now all
clients are pre-registered in a client array at compile time, and at run
time they merely check-in with the infrastructure to pass their callback
table for inclusion in the pre-sized client array.

This also allows for future cleanups and removal of unneeded code in the
iwcm* netlink handler.

Signed-off-by: Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
Reviewed-by: Chien Tin Tung <chien.tin.tung-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
drivers/infiniband/core/cma.c | 6 +-
drivers/infiniband/core/core_priv.h | 4 +-
drivers/infiniband/core/device.c | 45 +++------
drivers/infiniband/core/iwcm.c | 10 +-
drivers/infiniband/core/netlink.c | 185 +++++++++++++++++-------------------
include/rdma/rdma_netlink.h | 13 +--
6 files changed, 112 insertions(+), 151 deletions(-)

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index ca4135c596ba..2a16a559bdda 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -4512,9 +4512,7 @@ static int __init cma_init(void)
if (ret)
goto err;

- if (ibnl_add_client(RDMA_NL_RDMA_CM, ARRAY_SIZE(cma_cb_table),
- cma_cb_table))
- pr_warn("RDMA CMA: failed to add netlink callback\n");
+ rdma_nl_register(RDMA_NL_RDMA_CM, cma_cb_table);
cma_configfs_init();

return 0;
@@ -4531,7 +4529,7 @@ static int __init cma_init(void)
static void __exit cma_cleanup(void)
{
cma_configfs_exit();
- ibnl_remove_client(RDMA_NL_RDMA_CM);
+ rdma_nl_unregister(RDMA_NL_RDMA_CM);
ib_unregister_client(&cma_client);
unregister_netdevice_notifier(&cma_nb);
rdma_addr_unregister_client(&addr_client);
diff --git a/drivers/infiniband/core/core_priv.h b/drivers/infiniband/core/core_priv.h
index 11ae67514e13..e759c27113cd 100644
--- a/drivers/infiniband/core/core_priv.h
+++ b/drivers/infiniband/core/core_priv.h
@@ -179,8 +179,8 @@ void ib_mad_cleanup(void);
int ib_sa_init(void);
void ib_sa_cleanup(void);

-int ibnl_init(void);
-void ibnl_cleanup(void);
+int rdma_nl_init(void);
+void rdma_nl_exit(void);

/**
* Check if there are any listeners to the netlink group
diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index a5dfab6adf49..d0994cd30eae 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -1086,29 +1086,15 @@ struct net_device *ib_get_net_dev_by_params(struct ib_device *dev,
}
EXPORT_SYMBOL(ib_get_net_dev_by_params);

-static struct ibnl_client_cbs ibnl_ls_cb_table[] = {
+static const struct ibnl_client_cbs ibnl_ls_cb_table[] = {
[RDMA_NL_LS_OP_RESOLVE] = {
- .dump = ib_nl_handle_resolve_resp,
- .module = THIS_MODULE },
+ .dump = ib_nl_handle_resolve_resp},
[RDMA_NL_LS_OP_SET_TIMEOUT] = {
- .dump = ib_nl_handle_set_timeout,
- .module = THIS_MODULE },
+ .dump = ib_nl_handle_set_timeout},
[RDMA_NL_LS_OP_IP_RESOLVE] = {
- .dump = ib_nl_handle_ip_res_resp,
- .module = THIS_MODULE },
+ .dump = ib_nl_handle_ip_res_resp},
};

-static int ib_add_ibnl_clients(void)
-{
- return ibnl_add_client(RDMA_NL_LS, ARRAY_SIZE(ibnl_ls_cb_table),
- ibnl_ls_cb_table);
-}
-
-static void ib_remove_ibnl_clients(void)
-{
- ibnl_remove_client(RDMA_NL_LS);
-}
-
static int __init ib_core_init(void)
{
int ret;
@@ -1130,9 +1116,9 @@ static int __init ib_core_init(void)
goto err_comp;
}

- ret = ibnl_init();
+ ret = rdma_nl_init();
if (ret) {
- pr_warn("Couldn't init IB netlink interface\n");
+ pr_warn("Couldn't init IB netlink interface: err %d\n", ret);
goto err_sysfs;
}

@@ -1154,24 +1140,17 @@ static int __init ib_core_init(void)
goto err_mad;
}

- ret = ib_add_ibnl_clients();
- if (ret) {
- pr_warn("Couldn't register ibnl clients\n");
- goto err_sa;
- }
-
ret = register_lsm_notifier(&ibdev_lsm_nb);
if (ret) {
pr_warn("Couldn't register LSM notifier. ret %d\n", ret);
- goto err_ibnl_clients;
+ goto err_sa;
}

+ rdma_nl_register(RDMA_NL_LS, ibnl_ls_cb_table);
ib_cache_setup();

return 0;

-err_ibnl_clients:
- ib_remove_ibnl_clients();
err_sa:
ib_sa_cleanup();
err_mad:
@@ -1179,7 +1158,7 @@ static int __init ib_core_init(void)
err_addr:
addr_cleanup();
err_ibnl:
- ibnl_cleanup();
+ rdma_nl_exit();
err_sysfs:
class_unregister(&ib_class);
err_comp:
@@ -1191,13 +1170,13 @@ static int __init ib_core_init(void)

static void __exit ib_core_cleanup(void)
{
- unregister_lsm_notifier(&ibdev_lsm_nb);
ib_cache_cleanup();
- ib_remove_ibnl_clients();
+ rdma_nl_unregister(RDMA_NL_LS);
+ unregister_lsm_notifier(&ibdev_lsm_nb);
ib_sa_cleanup();
ib_mad_cleanup();
addr_cleanup();
- ibnl_cleanup();
+ rdma_nl_exit();
class_unregister(&ib_class);
destroy_workqueue(ib_comp_wq);
/* Make sure that any pending umem accounting work is done. */
diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
index 31661b5c1743..8599271d8be6 100644
--- a/drivers/infiniband/core/iwcm.c
+++ b/drivers/infiniband/core/iwcm.c
@@ -1175,12 +1175,8 @@ static int __init iw_cm_init(void)
ret = iwpm_init(RDMA_NL_IWCM);
if (ret)
pr_err("iw_cm: couldn't init iwpm\n");
-
- ret = ibnl_add_client(RDMA_NL_IWCM, ARRAY_SIZE(iwcm_nl_cb_table),
- iwcm_nl_cb_table);
- if (ret)
- pr_err("iw_cm: couldn't register netlink callbacks\n");
-
+ else
+ rdma_nl_register(RDMA_NL_IWCM, iwcm_nl_cb_table);
iwcm_wq = alloc_ordered_workqueue("iw_cm_wq", WQ_MEM_RECLAIM);
if (!iwcm_wq)
return -ENOMEM;
@@ -1200,7 +1196,7 @@ static void __exit iw_cm_cleanup(void)
{
unregister_net_sysctl_table(iwcm_ctl_table_hdr);
destroy_workqueue(iwcm_wq);
- ibnl_remove_client(RDMA_NL_IWCM);
+ rdma_nl_unregister(RDMA_NL_IWCM);
iwpm_exit(RDMA_NL_IWCM);
}

diff --git a/drivers/infiniband/core/netlink.c b/drivers/infiniband/core/netlink.c
index 0fc50e15ae22..06f7ba31fbdd 100644
--- a/drivers/infiniband/core/netlink.c
+++ b/drivers/infiniband/core/netlink.c
@@ -39,16 +39,13 @@
#include <rdma/rdma_netlink.h>
#include "core_priv.h"

-struct ibnl_client {
- struct list_head list;
- int index;
- int nops;
- const struct ibnl_client_cbs *cb_table;
-};
+#include "core_priv.h"

-static DEFINE_MUTEX(ibnl_mutex);
+static DEFINE_MUTEX(rdma_nl_mutex);
static struct sock *nls;
-static LIST_HEAD(client_list);
+static struct {
+ const struct ibnl_client_cbs *cb_table;
+} rdma_nl_types[RDMA_NL_NUM_CLIENTS];

int ibnl_chk_listeners(unsigned int group)
{
@@ -57,58 +54,74 @@ int ibnl_chk_listeners(unsigned int group)
return 0;
}

-int ibnl_add_client(int index, int nops,
- const struct ibnl_client_cbs cb_table[])
+static bool is_nl_msg_valid(unsigned int type, unsigned int op)
{
- struct ibnl_client *cur;
- struct ibnl_client *nl_client;
+ static const unsigned int max_num_ops[RDMA_NL_NUM_CLIENTS - 1] = {
+ RDMA_NL_RDMA_CM_NUM_OPS,
+ RDMA_NL_IWPM_NUM_OPS,
+ 0,
+ RDMA_NL_LS_NUM_OPS,
+ 0 };

- nl_client = kmalloc(sizeof *nl_client, GFP_KERNEL);
- if (!nl_client)
- return -ENOMEM;
+ /*
+ * This BUILD_BUG_ON is intended to catch addition of new
+ * RDMA netlink protocol without updating the array above.
+ */
+ BUILD_BUG_ON(RDMA_NL_NUM_CLIENTS != 6);

- nl_client->index = index;
- nl_client->nops = nops;
- nl_client->cb_table = cb_table;
+ if (type > RDMA_NL_NUM_CLIENTS - 1)
+ return false;

- mutex_lock(&ibnl_mutex);
+ return (op < max_num_ops[type - 1]) ? true : false;
+}

- list_for_each_entry(cur, &client_list, list) {
- if (cur->index == index) {
- pr_warn("Client for %d already exists\n", index);
- mutex_unlock(&ibnl_mutex);
- kfree(nl_client);
- return -EINVAL;
- }
- }
+static bool is_nl_valid(unsigned int type, unsigned int op)
+{
+ if (!is_nl_msg_valid(type, op) ||
+ !rdma_nl_types[type].cb_table ||
+ !rdma_nl_types[type].cb_table[op].dump)
+ return false;
+ return true;
+}

- list_add_tail(&nl_client->list, &client_list);
+void rdma_nl_register(unsigned int index,
+ const struct ibnl_client_cbs cb_table[])
+{
+ mutex_lock(&rdma_nl_mutex);
+ if (!is_nl_msg_valid(index, 0)) {
+ /*
+ * All clients are not interesting in success/failure of
+ * this call. They want to see the print to error log and
+ * continue their initialization. Print warning for them,
+ * because it is programmer's error to be here.
+ */
+ mutex_unlock(&rdma_nl_mutex);
+ WARN(true,
+ "The not-valid %u index was supplied to RDMA netlink\n",
+ index);
+ return;
+ }

- mutex_unlock(&ibnl_mutex);
+ if (rdma_nl_types[index].cb_table) {
+ mutex_unlock(&rdma_nl_mutex);
+ WARN(true,
+ "The %u index is already registered in RDMA netlink\n",
+ index);
+ return;
+ }

- return 0;
+ rdma_nl_types[index].cb_table = cb_table;
+ mutex_unlock(&rdma_nl_mutex);
}
-EXPORT_SYMBOL(ibnl_add_client);
+EXPORT_SYMBOL(rdma_nl_register);

-int ibnl_remove_client(int index)
+void rdma_nl_unregister(unsigned int index)
{
- struct ibnl_client *cur, *next;
-
- mutex_lock(&ibnl_mutex);
- list_for_each_entry_safe(cur, next, &client_list, list) {
- if (cur->index == index) {
- list_del(&(cur->list));
- mutex_unlock(&ibnl_mutex);
- kfree(cur);
- return 0;
- }
- }
- pr_warn("Can't remove callback for client idx %d. Not found\n", index);
- mutex_unlock(&ibnl_mutex);
-
- return -EINVAL;
+ mutex_lock(&rdma_nl_mutex);
+ rdma_nl_types[index].cb_table = NULL;
+ mutex_unlock(&rdma_nl_mutex);
}
-EXPORT_SYMBOL(ibnl_remove_client);
+EXPORT_SYMBOL(rdma_nl_unregister);

void *ibnl_put_msg(struct sk_buff *skb, struct nlmsghdr **nlh, int seq,
int len, int client, int op, int flags)
@@ -149,45 +162,31 @@ EXPORT_SYMBOL(ibnl_put_attr);
static int ibnl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack)
{
- struct ibnl_client *client;
int type = nlh->nlmsg_type;
- int index = RDMA_NL_GET_CLIENT(type);
+ unsigned int index = RDMA_NL_GET_CLIENT(type);
unsigned int op = RDMA_NL_GET_OP(type);
+ struct netlink_callback cb = {};
+ struct netlink_dump_control c = {};

- list_for_each_entry(client, &client_list, list) {
- if (client->index == index) {
- if (op >= client->nops || !client->cb_table[op].dump)
- return -EINVAL;
-
- /*
- * For response or local service set_timeout request,
- * there is no need to use netlink_dump_start.
- */
- if (!(nlh->nlmsg_flags & NLM_F_REQUEST) ||
- (index == RDMA_NL_LS &&
- op == RDMA_NL_LS_OP_SET_TIMEOUT)) {
- struct netlink_callback cb = {
- .skb = skb,
- .nlh = nlh,
- .dump = client->cb_table[op].dump,
- .module = client->cb_table[op].module,
- };
-
- return cb.dump(skb, &cb);
- }
-
- {
- struct netlink_dump_control c = {
- .dump = client->cb_table[op].dump,
- .module = client->cb_table[op].module,
- };
- return netlink_dump_start(nls, skb, nlh, &c);
- }
- }
+ if (!is_nl_valid(index, op))
+ return -EINVAL;
+
+ /*
+ * For response or local service set_timeout request,
+ * there is no need to use netlink_dump_start.
+ */
+ if (!(nlh->nlmsg_flags & NLM_F_REQUEST) ||
+ (index == RDMA_NL_LS && op == RDMA_NL_LS_OP_SET_TIMEOUT)) {
+ cb.skb = skb;
+ cb.nlh = nlh;
+ cb.dump = rdma_nl_types[index].cb_table[op].dump;
+ cb.module = rdma_nl_types[index].cb_table[op].module;
+ return cb.dump(skb, &cb);
}

- pr_info("Index %d wasn't found in client list\n", index);
- return -EINVAL;
+ c.dump = rdma_nl_types[index].cb_table[op].dump;
+ c.module = rdma_nl_types[index].cb_table[op].module;
+ return netlink_dump_start(nls, skb, nlh, &c);
}

static void ibnl_rcv_reply_skb(struct sk_buff *skb)
@@ -221,10 +220,10 @@ static void ibnl_rcv_reply_skb(struct sk_buff *skb)

static void ibnl_rcv(struct sk_buff *skb)
{
- mutex_lock(&ibnl_mutex);
+ mutex_lock(&rdma_nl_mutex);
ibnl_rcv_reply_skb(skb);
netlink_rcv_skb(skb, &ibnl_rcv_msg);
- mutex_unlock(&ibnl_mutex);
+ mutex_unlock(&rdma_nl_mutex);
}

int ibnl_unicast(struct sk_buff *skb, struct nlmsghdr *nlh,
@@ -254,32 +253,26 @@ int ibnl_multicast(struct sk_buff *skb, struct nlmsghdr *nlh,
}
EXPORT_SYMBOL(ibnl_multicast);

-int __init ibnl_init(void)
+int __init rdma_nl_init(void)
{
struct netlink_kernel_cfg cfg = {
.input = ibnl_rcv,
};

nls = netlink_kernel_create(&init_net, NETLINK_RDMA, &cfg);
- if (!nls) {
- pr_warn("Failed to create netlink socket\n");
+ if (!nls)
return -ENOMEM;
- }

nls->sk_sndtimeo = 10 * HZ;
return 0;
}

-void ibnl_cleanup(void)
+void rdma_nl_exit(void)
{
- struct ibnl_client *cur, *next;
+ int idx;

- mutex_lock(&ibnl_mutex);
- list_for_each_entry_safe(cur, next, &client_list, list) {
- list_del(&(cur->list));
- kfree(cur);
- }
- mutex_unlock(&ibnl_mutex);
+ for (idx = 0; idx < RDMA_NL_NUM_CLIENTS; idx++)
+ rdma_nl_unregister(idx);

netlink_kernel_release(nls);
}
diff --git a/include/rdma/rdma_netlink.h b/include/rdma/rdma_netlink.h
index 5b1466770917..aadf0ab963b2 100644
--- a/include/rdma/rdma_netlink.h
+++ b/include/rdma/rdma_netlink.h
@@ -11,23 +11,18 @@ struct ibnl_client_cbs {
};

/**
- * Add a a client to the list of IB netlink exporters.
+ * Register client in RDMA netlink.
* @index: Index of the added client
- * @nops: Number of supported ops by the added client.
* @cb_table: A table for op->callback
- *
- * Returns 0 on success or a negative error code.
*/
-int ibnl_add_client(int index, int nops,
- const struct ibnl_client_cbs cb_table[]);
+void rdma_nl_register(unsigned int index,
+ const struct ibnl_client_cbs cb_table[]);

/**
* Remove a client from IB netlink.
* @index: Index of the removed IB client.
- *
- * Returns 0 on success or a negative error code.
*/
-int ibnl_remove_client(int index);
+void rdma_nl_unregister(unsigned int index);

/**
* Put a new message in a supplied skb.