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Jiri Pirkodavem330
Jiri Pirko
authored and
davem330
committed
devlink: introduce object and nested devlink relationship infra
It is a bit tricky to maintain relationship between devlink objects and nested devlink instances due to following aspects: 1) Locking. It is necessary to lock the devlink instance that contains the object first, only after that to lock the nested instance. 2) Lifetimes. Objects (e.g devlink port) may be removed before the nested devlink instance. 3) Notifications. If nested instance changes (e.g. gets registered/unregistered) the nested-in object needs to send appropriate notifications. Resolve this by introducing an xarray that holds 1:1 relationships between devlink object and related nested devlink instance. Use that xarray index to get the object/nested devlink instance on the other side. Provide necessary helpers: devlink_rel_nested_in_add/clear() to add and clear the relationship. devlink_rel_nested_in_notify() to call the nested-in object to send notifications during nested instance register/unregister/netns change. devlink_rel_devlink_handle_put() to be used by nested-in object fill function to fill the nested handle. Signed-off-by: Jiri Pirko <[email protected]> Signed-off-by: David S. Miller <[email protected]>
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‎net/devlink/core.c

Lines changed: 215 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -16,6 +16,219 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(devlink_trap_report);
1616

1717
DEFINE_XARRAY_FLAGS(devlinks, XA_FLAGS_ALLOC);
1818

19+
static struct devlink *devlinks_xa_get(unsigned long index)
20+
{
21+
struct devlink *devlink;
22+
23+
rcu_read_lock();
24+
devlink = xa_find(&devlinks, &index, index, DEVLINK_REGISTERED);
25+
if (!devlink || !devlink_try_get(devlink))
26+
devlink = NULL;
27+
rcu_read_unlock();
28+
return devlink;
29+
}
30+
31+
/* devlink_rels xarray contains 1:1 relationships between
32+
* devlink object and related nested devlink instance.
33+
* The xarray index is used to get the nested object from
34+
* the nested-in object code.
35+
*/
36+
static DEFINE_XARRAY_FLAGS(devlink_rels, XA_FLAGS_ALLOC1);
37+
38+
#define DEVLINK_REL_IN_USE XA_MARK_0
39+
40+
struct devlink_rel {
41+
u32 index;
42+
refcount_t refcount;
43+
u32 devlink_index;
44+
struct {
45+
u32 devlink_index;
46+
u32 obj_index;
47+
devlink_rel_notify_cb_t *notify_cb;
48+
devlink_rel_cleanup_cb_t *cleanup_cb;
49+
struct work_struct notify_work;
50+
} nested_in;
51+
};
52+
53+
static void devlink_rel_free(struct devlink_rel *rel)
54+
{
55+
xa_erase(&devlink_rels, rel->index);
56+
kfree(rel);
57+
}
58+
59+
static void __devlink_rel_get(struct devlink_rel *rel)
60+
{
61+
refcount_inc(&rel->refcount);
62+
}
63+
64+
static void __devlink_rel_put(struct devlink_rel *rel)
65+
{
66+
if (refcount_dec_and_test(&rel->refcount))
67+
devlink_rel_free(rel);
68+
}
69+
70+
static void devlink_rel_nested_in_notify_work(struct work_struct *work)
71+
{
72+
struct devlink_rel *rel = container_of(work, struct devlink_rel,
73+
nested_in.notify_work);
74+
struct devlink *devlink;
75+
76+
devlink = devlinks_xa_get(rel->nested_in.devlink_index);
77+
if (!devlink)
78+
goto rel_put;
79+
if (!devl_trylock(devlink)) {
80+
devlink_put(devlink);
81+
goto reschedule_work;
82+
}
83+
if (!devl_is_registered(devlink)) {
84+
devl_unlock(devlink);
85+
devlink_put(devlink);
86+
goto rel_put;
87+
}
88+
if (!xa_get_mark(&devlink_rels, rel->index, DEVLINK_REL_IN_USE))
89+
rel->nested_in.cleanup_cb(devlink, rel->nested_in.obj_index, rel->index);
90+
rel->nested_in.notify_cb(devlink, rel->nested_in.obj_index);
91+
devl_unlock(devlink);
92+
devlink_put(devlink);
93+
94+
rel_put:
95+
__devlink_rel_put(rel);
96+
return;
97+
98+
reschedule_work:
99+
schedule_work(&rel->nested_in.notify_work);
100+
}
101+
102+
static void devlink_rel_nested_in_notify_work_schedule(struct devlink_rel *rel)
103+
{
104+
__devlink_rel_get(rel);
105+
schedule_work(&rel->nested_in.notify_work);
106+
}
107+
108+
static struct devlink_rel *devlink_rel_alloc(void)
109+
{
110+
struct devlink_rel *rel;
111+
static u32 next;
112+
int err;
113+
114+
rel = kzalloc(sizeof(*rel), GFP_KERNEL);
115+
if (!rel)
116+
return ERR_PTR(-ENOMEM);
117+
118+
err = xa_alloc_cyclic(&devlink_rels, &rel->index, rel,
119+
xa_limit_32b, &next, GFP_KERNEL);
120+
if (err) {
121+
kfree(rel);
122+
return ERR_PTR(err);
123+
}
124+
125+
refcount_set(&rel->refcount, 1);
126+
INIT_WORK(&rel->nested_in.notify_work,
127+
&devlink_rel_nested_in_notify_work);
128+
return rel;
129+
}
130+
131+
static void devlink_rel_put(struct devlink *devlink)
132+
{
133+
struct devlink_rel *rel = devlink->rel;
134+
135+
if (!rel)
136+
return;
137+
xa_clear_mark(&devlink_rels, rel->index, DEVLINK_REL_IN_USE);
138+
devlink_rel_nested_in_notify_work_schedule(rel);
139+
__devlink_rel_put(rel);
140+
devlink->rel = NULL;
141+
}
142+
143+
void devlink_rel_nested_in_clear(u32 rel_index)
144+
{
145+
xa_clear_mark(&devlink_rels, rel_index, DEVLINK_REL_IN_USE);
146+
}
147+
148+
int devlink_rel_nested_in_add(u32 *rel_index, u32 devlink_index,
149+
u32 obj_index, devlink_rel_notify_cb_t *notify_cb,
150+
devlink_rel_cleanup_cb_t *cleanup_cb,
151+
struct devlink *devlink)
152+
{
153+
struct devlink_rel *rel = devlink_rel_alloc();
154+
155+
ASSERT_DEVLINK_NOT_REGISTERED(devlink);
156+
157+
if (IS_ERR(rel))
158+
return PTR_ERR(rel);
159+
160+
rel->devlink_index = devlink->index;
161+
rel->nested_in.devlink_index = devlink_index;
162+
rel->nested_in.obj_index = obj_index;
163+
rel->nested_in.notify_cb = notify_cb;
164+
rel->nested_in.cleanup_cb = cleanup_cb;
165+
*rel_index = rel->index;
166+
xa_set_mark(&devlink_rels, rel->index, DEVLINK_REL_IN_USE);
167+
devlink->rel = rel;
168+
return 0;
169+
}
170+
171+
void devlink_rel_nested_in_notify(struct devlink *devlink)
172+
{
173+
struct devlink_rel *rel = devlink->rel;
174+
175+
if (!rel)
176+
return;
177+
devlink_rel_nested_in_notify_work_schedule(rel);
178+
}
179+
180+
static struct devlink_rel *devlink_rel_find(unsigned long rel_index)
181+
{
182+
return xa_find(&devlink_rels, &rel_index, rel_index,
183+
DEVLINK_REL_IN_USE);
184+
}
185+
186+
static struct devlink *devlink_rel_devlink_get_lock(u32 rel_index)
187+
{
188+
struct devlink *devlink;
189+
struct devlink_rel *rel;
190+
u32 devlink_index;
191+
192+
if (!rel_index)
193+
return NULL;
194+
xa_lock(&devlink_rels);
195+
rel = devlink_rel_find(rel_index);
196+
if (rel)
197+
devlink_index = rel->devlink_index;
198+
xa_unlock(&devlink_rels);
199+
if (!rel)
200+
return NULL;
201+
devlink = devlinks_xa_get(devlink_index);
202+
if (!devlink)
203+
return NULL;
204+
devl_lock(devlink);
205+
if (!devl_is_registered(devlink)) {
206+
devl_unlock(devlink);
207+
devlink_put(devlink);
208+
return NULL;
209+
}
210+
return devlink;
211+
}
212+
213+
int devlink_rel_devlink_handle_put(struct sk_buff *msg, struct devlink *devlink,
214+
u32 rel_index, int attrtype,
215+
bool *msg_updated)
216+
{
217+
struct net *net = devlink_net(devlink);
218+
struct devlink *rel_devlink;
219+
int err;
220+
221+
rel_devlink = devlink_rel_devlink_get_lock(rel_index);
222+
if (!rel_devlink)
223+
return 0;
224+
err = devlink_nl_put_nested_handle(msg, net, rel_devlink, attrtype);
225+
devl_unlock(rel_devlink);
226+
devlink_put(rel_devlink);
227+
if (!err && msg_updated)
228+
*msg_updated = true;
229+
return err;
230+
}
231+
19232
void *devlink_priv(struct devlink *devlink)
20233
{
21234
return &devlink->priv;
@@ -142,6 +355,7 @@ int devl_register(struct devlink *devlink)
142355

143356
xa_set_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
144357
devlink_notify_register(devlink);
358+
devlink_rel_nested_in_notify(devlink);
145359

146360
return 0;
147361
}
@@ -166,6 +380,7 @@ void devl_unregister(struct devlink *devlink)
166380

167381
devlink_notify_unregister(devlink);
168382
xa_clear_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
383+
devlink_rel_put(devlink);
169384
}
170385
EXPORT_SYMBOL_GPL(devl_unregister);
171386

‎net/devlink/dev.c

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -372,6 +372,7 @@ static void devlink_reload_netns_change(struct devlink *devlink,
372372
devlink_notify_unregister(devlink);
373373
write_pnet(&devlink->_net, dest_net);
374374
devlink_notify_register(devlink);
375+
devlink_rel_nested_in_notify(devlink);
375376
}
376377

377378
int devlink_reload(struct devlink *devlink, struct net *dest_net,

‎net/devlink/devl_internal.h

Lines changed: 17 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -17,6 +17,8 @@
1717

1818
#include "netlink_gen.h"
1919

20+
struct devlink_rel;
21+
2022
#define DEVLINK_REGISTERED XA_MARK_1
2123

2224
#define DEVLINK_RELOAD_STATS_ARRAY_SIZE \
@@ -55,6 +57,7 @@ struct devlink {
5557
u8 reload_failed:1;
5658
refcount_t refcount;
5759
struct rcu_work rwork;
60+
struct devlink_rel *rel;
5861
char priv[] __aligned(NETDEV_ALIGN);
5962
};
6063

@@ -92,6 +95,20 @@ static inline bool devl_is_registered(struct devlink *devlink)
9295
return xa_get_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);
9396
}
9497

98+
typedef void devlink_rel_notify_cb_t(struct devlink *devlink, u32 obj_index);
99+
typedef void devlink_rel_cleanup_cb_t(struct devlink *devlink, u32 obj_index,
100+
u32 rel_index);
101+
102+
void devlink_rel_nested_in_clear(u32 rel_index);
103+
int devlink_rel_nested_in_add(u32 *rel_index, u32 devlink_index,
104+
u32 obj_index, devlink_rel_notify_cb_t *notify_cb,
105+
devlink_rel_cleanup_cb_t *cleanup_cb,
106+
struct devlink *devlink);
107+
void devlink_rel_nested_in_notify(struct devlink *devlink);
108+
int devlink_rel_devlink_handle_put(struct sk_buff *msg, struct devlink *devlink,
109+
u32 rel_index, int attrtype,
110+
bool *msg_updated);
111+
95112
/* Netlink */
96113
#define DEVLINK_NL_FLAG_NEED_PORT BIT(0)
97114
#define DEVLINK_NL_FLAG_NEED_DEVLINK_OR_PORT BIT(1)

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