| Message ID | 20240131123544.462597-2-tobias@waldekranz.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: bridge: switchdev: Skip MDB replays of pending events | expand |
Wed, Jan 31, 2024 at 01:35:43PM CET, tobias@waldekranz.com wrote: >When adding/removing a port to/from a bridge, the port must be brought >up to speed with the current state of the bridge. This is done by >replaying all relevant events, directly to the port in question. Could you please use the imperative mood in your patch descriptions? That way, it is much easier to understand what is the current state of things and what you are actually changing. https://www.kernel.org/doc/html/v6.7/process/submitting-patches.html#describe-your-changes While at it, could you also fix your cover letter so the reader can actually tell what's the current state and what the patchset is doing? pw-bot: cr > >In some situations, specifically when replaying the MDB, this process >may race against new events that are generated concurrently. So the >bridge must ensure that the event is not already pending on the >deferred queue. switchdev_port_obj_is_deferred answers this question. > >Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> >--- > include/net/switchdev.h | 3 ++ > net/switchdev/switchdev.c | 61 +++++++++++++++++++++++++++++++++++++++ > 2 files changed, 64 insertions(+) > >diff --git a/include/net/switchdev.h b/include/net/switchdev.h >index a43062d4c734..538851a93d9e 100644 >--- a/include/net/switchdev.h >+++ b/include/net/switchdev.h >@@ -308,6 +308,9 @@ void switchdev_deferred_process(void); > int switchdev_port_attr_set(struct net_device *dev, > const struct switchdev_attr *attr, > struct netlink_ext_ack *extack); >+bool switchdev_port_obj_is_deferred(struct net_device *dev, >+ enum switchdev_notifier_type nt, >+ const struct switchdev_obj *obj); > int switchdev_port_obj_add(struct net_device *dev, > const struct switchdev_obj *obj, > struct netlink_ext_ack *extack); >diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c >index 5b045284849e..40bb17c7fdbf 100644 >--- a/net/switchdev/switchdev.c >+++ b/net/switchdev/switchdev.c >@@ -19,6 +19,35 @@ > #include <linux/rtnetlink.h> > #include <net/switchdev.h> > >+static bool switchdev_obj_eq(const struct switchdev_obj *a, >+ const struct switchdev_obj *b) >+{ >+ const struct switchdev_obj_port_vlan *va, *vb; >+ const struct switchdev_obj_port_mdb *ma, *mb; >+ >+ if (a->id != b->id || a->orig_dev != b->orig_dev) >+ return false; >+ >+ switch (a->id) { >+ case SWITCHDEV_OBJ_ID_PORT_VLAN: >+ va = SWITCHDEV_OBJ_PORT_VLAN(a); >+ vb = SWITCHDEV_OBJ_PORT_VLAN(b); >+ return va->flags == vb->flags && >+ va->vid == vb->vid && >+ va->changed == vb->changed; >+ case SWITCHDEV_OBJ_ID_PORT_MDB: >+ case SWITCHDEV_OBJ_ID_HOST_MDB: >+ ma = SWITCHDEV_OBJ_PORT_MDB(a); >+ mb = SWITCHDEV_OBJ_PORT_MDB(b); >+ return ma->vid == mb->vid && >+ !memcmp(ma->addr, mb->addr, sizeof(ma->addr)); >+ default: >+ break; >+ } >+ >+ BUG(); >+} >+ > static LIST_HEAD(deferred); > static DEFINE_SPINLOCK(deferred_lock); > >@@ -307,6 +336,38 @@ int switchdev_port_obj_del(struct net_device *dev, > } > EXPORT_SYMBOL_GPL(switchdev_port_obj_del); > >+bool switchdev_port_obj_is_deferred(struct net_device *dev, >+ enum switchdev_notifier_type nt, >+ const struct switchdev_obj *obj) >+{ >+ struct switchdev_deferred_item *dfitem; >+ bool found = false; >+ >+ ASSERT_RTNL(); >+ >+ spin_lock_bh(&deferred_lock); >+ >+ list_for_each_entry(dfitem, &deferred, list) { >+ if (dfitem->dev != dev) >+ continue; >+ >+ if ((dfitem->func == switchdev_port_obj_add_deferred && >+ nt == SWITCHDEV_PORT_OBJ_ADD) || >+ (dfitem->func == switchdev_port_obj_del_deferred && >+ nt == SWITCHDEV_PORT_OBJ_DEL)) { >+ if (switchdev_obj_eq((const void *)dfitem->data, obj)) { >+ found = true; >+ break; >+ } >+ } >+ } >+ >+ spin_unlock_bh(&deferred_lock); >+ >+ return found; >+} >+EXPORT_SYMBOL_GPL(switchdev_port_obj_is_deferred); >+ > static ATOMIC_NOTIFIER_HEAD(switchdev_notif_chain); > static BLOCKING_NOTIFIER_HEAD(switchdev_blocking_notif_chain); > >-- >2.34.1 >
On ons, jan 31, 2024 at 13:50, Jiri Pirko <jiri@resnulli.us> wrote: > Wed, Jan 31, 2024 at 01:35:43PM CET, tobias@waldekranz.com wrote: >>When adding/removing a port to/from a bridge, the port must be brought >>up to speed with the current state of the bridge. This is done by >>replaying all relevant events, directly to the port in question. > > Could you please use the imperative mood in your patch descriptions? > That way, it is much easier to understand what is the current state of > things and what you are actually changing. > > https://www.kernel.org/doc/html/v6.7/process/submitting-patches.html#describe-your-changes > > While at it, could you also fix your cover letter so the reader can > actually tell what's the current state and what the patchset is doing? Sure thing. Do you feel that this is enough of an issue that it blocks you from doing a review of v1, or can I wait for more feedback and bake it in with other changes?
On Wed, Jan 31, 2024 at 01:35:43PM +0100, Tobias Waldekranz wrote: > When adding/removing a port to/from a bridge, the port must be brought > up to speed with the current state of the bridge. This is done by > replaying all relevant events, directly to the port in question. > > In some situations, specifically when replaying the MDB, this process > may race against new events that are generated concurrently. > > So the bridge must ensure that the event is not already pending on the > deferred queue. switchdev_port_obj_is_deferred answers this question. > > Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> I don't see great value in splitting this patch in (1) unused helpers (2) actual fix that uses them. Especially since it creates confusion - it is nowhere made clear in this commit message that it is just preparatory work. > --- > include/net/switchdev.h | 3 ++ > net/switchdev/switchdev.c | 61 +++++++++++++++++++++++++++++++++++++++ > 2 files changed, 64 insertions(+) > > diff --git a/include/net/switchdev.h b/include/net/switchdev.h > index a43062d4c734..538851a93d9e 100644 > --- a/include/net/switchdev.h > +++ b/include/net/switchdev.h > @@ -308,6 +308,9 @@ void switchdev_deferred_process(void); > int switchdev_port_attr_set(struct net_device *dev, > const struct switchdev_attr *attr, > struct netlink_ext_ack *extack); > +bool switchdev_port_obj_is_deferred(struct net_device *dev, > + enum switchdev_notifier_type nt, > + const struct switchdev_obj *obj); I think this is missing a shim definition for when CONFIG_NET_SWITCHDEV is disabled. > int switchdev_port_obj_add(struct net_device *dev, > const struct switchdev_obj *obj, > struct netlink_ext_ack *extack); > diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c > index 5b045284849e..40bb17c7fdbf 100644 > --- a/net/switchdev/switchdev.c > +++ b/net/switchdev/switchdev.c > @@ -19,6 +19,35 @@ > #include <linux/rtnetlink.h> > #include <net/switchdev.h> > > +static bool switchdev_obj_eq(const struct switchdev_obj *a, > + const struct switchdev_obj *b) > +{ > + const struct switchdev_obj_port_vlan *va, *vb; > + const struct switchdev_obj_port_mdb *ma, *mb; > + > + if (a->id != b->id || a->orig_dev != b->orig_dev) > + return false; > + > + switch (a->id) { > + case SWITCHDEV_OBJ_ID_PORT_VLAN: > + va = SWITCHDEV_OBJ_PORT_VLAN(a); > + vb = SWITCHDEV_OBJ_PORT_VLAN(b); > + return va->flags == vb->flags && > + va->vid == vb->vid && > + va->changed == vb->changed; > + case SWITCHDEV_OBJ_ID_PORT_MDB: > + case SWITCHDEV_OBJ_ID_HOST_MDB: > + ma = SWITCHDEV_OBJ_PORT_MDB(a); > + mb = SWITCHDEV_OBJ_PORT_MDB(b); > + return ma->vid == mb->vid && > + !memcmp(ma->addr, mb->addr, sizeof(ma->addr)); ether_addr_equal(). > + default: > + break; Does C allow you to not return anything here? > + } > + > + BUG(); > +} > + > static LIST_HEAD(deferred); > static DEFINE_SPINLOCK(deferred_lock); > > @@ -307,6 +336,38 @@ int switchdev_port_obj_del(struct net_device *dev, > } > EXPORT_SYMBOL_GPL(switchdev_port_obj_del); > > +bool switchdev_port_obj_is_deferred(struct net_device *dev, > + enum switchdev_notifier_type nt, > + const struct switchdev_obj *obj) A kernel-doc comment would be great. It looks like it's not returning whether the port object is deferred, but whether the _action_ given by @nt on the @obj is deferred. This further distinguishes between deferred additions and deferred removals. > +{ > + struct switchdev_deferred_item *dfitem; > + bool found = false; > + > + ASSERT_RTNL(); Why does rtnl_lock() have to be held? To fully allow switchdev_deferred_process() to run to completion, aka its dfitem->func() as well? > + > + spin_lock_bh(&deferred_lock); > + > + list_for_each_entry(dfitem, &deferred, list) { > + if (dfitem->dev != dev) > + continue; > + > + if ((dfitem->func == switchdev_port_obj_add_deferred && > + nt == SWITCHDEV_PORT_OBJ_ADD) || > + (dfitem->func == switchdev_port_obj_del_deferred && > + nt == SWITCHDEV_PORT_OBJ_DEL)) { > + if (switchdev_obj_eq((const void *)dfitem->data, obj)) { > + found = true; > + break; > + } > + } > + } > + > + spin_unlock_bh(&deferred_lock); > + > + return found; > +} > +EXPORT_SYMBOL_GPL(switchdev_port_obj_is_deferred); > + > static ATOMIC_NOTIFIER_HEAD(switchdev_notif_chain); > static BLOCKING_NOTIFIER_HEAD(switchdev_blocking_notif_chain); > > -- > 2.34.1 >
On ons, jan 31, 2024 at 15:34, Vladimir Oltean <olteanv@gmail.com> wrote: > On Wed, Jan 31, 2024 at 01:35:43PM +0100, Tobias Waldekranz wrote: >> When adding/removing a port to/from a bridge, the port must be brought >> up to speed with the current state of the bridge. This is done by >> replaying all relevant events, directly to the port in question. >> >> In some situations, specifically when replaying the MDB, this process >> may race against new events that are generated concurrently. >> >> So the bridge must ensure that the event is not already pending on the >> deferred queue. switchdev_port_obj_is_deferred answers this question. >> >> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> > > I don't see great value in splitting this patch in (1) unused helpers > (2) actual fix that uses them. Especially since it creates confusion - > it is nowhere made clear in this commit message that it is just > preparatory work. It was one commit until the last minute, I'll squash them back together. >> --- >> include/net/switchdev.h | 3 ++ >> net/switchdev/switchdev.c | 61 +++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 64 insertions(+) >> >> diff --git a/include/net/switchdev.h b/include/net/switchdev.h >> index a43062d4c734..538851a93d9e 100644 >> --- a/include/net/switchdev.h >> +++ b/include/net/switchdev.h >> @@ -308,6 +308,9 @@ void switchdev_deferred_process(void); >> int switchdev_port_attr_set(struct net_device *dev, >> const struct switchdev_attr *attr, >> struct netlink_ext_ack *extack); >> +bool switchdev_port_obj_is_deferred(struct net_device *dev, >> + enum switchdev_notifier_type nt, >> + const struct switchdev_obj *obj); > > I think this is missing a shim definition for when CONFIG_NET_SWITCHDEV > is disabled. Even though the only caller is br_switchdev.c, which is guarded behind CONFIG_NET_SWITCHDEV? >> int switchdev_port_obj_add(struct net_device *dev, >> const struct switchdev_obj *obj, >> struct netlink_ext_ack *extack); >> diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c >> index 5b045284849e..40bb17c7fdbf 100644 >> --- a/net/switchdev/switchdev.c >> +++ b/net/switchdev/switchdev.c >> @@ -19,6 +19,35 @@ >> #include <linux/rtnetlink.h> >> #include <net/switchdev.h> >> >> +static bool switchdev_obj_eq(const struct switchdev_obj *a, >> + const struct switchdev_obj *b) >> +{ >> + const struct switchdev_obj_port_vlan *va, *vb; >> + const struct switchdev_obj_port_mdb *ma, *mb; >> + >> + if (a->id != b->id || a->orig_dev != b->orig_dev) >> + return false; >> + >> + switch (a->id) { >> + case SWITCHDEV_OBJ_ID_PORT_VLAN: >> + va = SWITCHDEV_OBJ_PORT_VLAN(a); >> + vb = SWITCHDEV_OBJ_PORT_VLAN(b); >> + return va->flags == vb->flags && >> + va->vid == vb->vid && >> + va->changed == vb->changed; >> + case SWITCHDEV_OBJ_ID_PORT_MDB: >> + case SWITCHDEV_OBJ_ID_HOST_MDB: >> + ma = SWITCHDEV_OBJ_PORT_MDB(a); >> + mb = SWITCHDEV_OBJ_PORT_MDB(b); >> + return ma->vid == mb->vid && >> + !memcmp(ma->addr, mb->addr, sizeof(ma->addr)); > > ether_addr_equal(). > >> + default: >> + break; > > Does C allow you to not return anything here? No warnings or errors are generated by my compiler (GCC 12.2.0). My guess is that the expansion of BUG() ends with __builtin_unreachable() or similar. >> + } >> + >> + BUG(); >> +} >> + >> static LIST_HEAD(deferred); >> static DEFINE_SPINLOCK(deferred_lock); >> >> @@ -307,6 +336,38 @@ int switchdev_port_obj_del(struct net_device *dev, >> } >> EXPORT_SYMBOL_GPL(switchdev_port_obj_del); >> >> +bool switchdev_port_obj_is_deferred(struct net_device *dev, >> + enum switchdev_notifier_type nt, >> + const struct switchdev_obj *obj) > > A kernel-doc comment would be great. It looks like it's not returning > whether the port object is deferred, but whether the _action_ given by > @nt on the @obj is deferred. This further distinguishes between deferred > additions and deferred removals. > Fair, so should the name change as well? I guess you'd want something like switchdev_port_obj_notification_is_deferred, but that sure is awfully long. >> +{ >> + struct switchdev_deferred_item *dfitem; >> + bool found = false; >> + >> + ASSERT_RTNL(); > > Why does rtnl_lock() have to be held? To fully allow switchdev_deferred_process() > to run to completion, aka its dfitem->func() as well? That is in effect what is does, yes. All we really would need is to ensure that any individual item that has been removed from the list has also executed its callback. But holding rtnl_lock was the most granular way I could see that would ensure that. >> + >> + spin_lock_bh(&deferred_lock); >> + >> + list_for_each_entry(dfitem, &deferred, list) { >> + if (dfitem->dev != dev) >> + continue; >> + >> + if ((dfitem->func == switchdev_port_obj_add_deferred && >> + nt == SWITCHDEV_PORT_OBJ_ADD) || >> + (dfitem->func == switchdev_port_obj_del_deferred && >> + nt == SWITCHDEV_PORT_OBJ_DEL)) { >> + if (switchdev_obj_eq((const void *)dfitem->data, obj)) { >> + found = true; >> + break; >> + } >> + } >> + } >> + >> + spin_unlock_bh(&deferred_lock); >> + >> + return found; >> +} >> +EXPORT_SYMBOL_GPL(switchdev_port_obj_is_deferred); >> + >> static ATOMIC_NOTIFIER_HEAD(switchdev_notif_chain); >> static BLOCKING_NOTIFIER_HEAD(switchdev_blocking_notif_chain); >> >> -- >> 2.34.1 >>
On Wed, Jan 31, 2024 at 03:48:05PM +0100, Tobias Waldekranz wrote: > >> +bool switchdev_port_obj_is_deferred(struct net_device *dev, > >> + enum switchdev_notifier_type nt, > >> + const struct switchdev_obj *obj); > > > > I think this is missing a shim definition for when CONFIG_NET_SWITCHDEV > > is disabled. > > Even though the only caller is br_switchdev.c, which is guarded behind > CONFIG_NET_SWITCHDEV? My mistake, please disregard. > >> int switchdev_port_obj_add(struct net_device *dev, > >> const struct switchdev_obj *obj, > >> struct netlink_ext_ack *extack); > >> diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c > >> index 5b045284849e..40bb17c7fdbf 100644 > >> --- a/net/switchdev/switchdev.c > >> +++ b/net/switchdev/switchdev.c > >> @@ -19,6 +19,35 @@ > >> #include <linux/rtnetlink.h> > >> #include <net/switchdev.h> > >> > >> +static bool switchdev_obj_eq(const struct switchdev_obj *a, > >> + const struct switchdev_obj *b) > >> +{ > >> + const struct switchdev_obj_port_vlan *va, *vb; > >> + const struct switchdev_obj_port_mdb *ma, *mb; > >> + > >> + if (a->id != b->id || a->orig_dev != b->orig_dev) > >> + return false; > >> + > >> + switch (a->id) { > >> + case SWITCHDEV_OBJ_ID_PORT_VLAN: > >> + va = SWITCHDEV_OBJ_PORT_VLAN(a); > >> + vb = SWITCHDEV_OBJ_PORT_VLAN(b); > >> + return va->flags == vb->flags && > >> + va->vid == vb->vid && > >> + va->changed == vb->changed; > >> + case SWITCHDEV_OBJ_ID_PORT_MDB: > >> + case SWITCHDEV_OBJ_ID_HOST_MDB: > >> + ma = SWITCHDEV_OBJ_PORT_MDB(a); > >> + mb = SWITCHDEV_OBJ_PORT_MDB(b); > >> + return ma->vid == mb->vid && > >> + !memcmp(ma->addr, mb->addr, sizeof(ma->addr)); > > > > ether_addr_equal(). > > > >> + default: > >> + break; > > > > Does C allow you to not return anything here? > > No warnings or errors are generated by my compiler (GCC 12.2.0). > > My guess is that the expansion of BUG() ends with > __builtin_unreachable() or similar. Interesting, I didn't know that. Although checkpatch says: "WARNING: Do not crash the kernel unless it is absolutely unavoidable--use WARN_ON_ONCE() plus recovery code (if feasible) instead of BUG() or variants". So I'm conflicted about what I just learned and how it can be applied in a way that checkpatch doesn't dislike. > > >> + } > >> + > >> + BUG(); > >> +} > >> + > >> static LIST_HEAD(deferred); > >> static DEFINE_SPINLOCK(deferred_lock); > >> > >> @@ -307,6 +336,38 @@ int switchdev_port_obj_del(struct net_device *dev, > >> } > >> EXPORT_SYMBOL_GPL(switchdev_port_obj_del); > >> > >> +bool switchdev_port_obj_is_deferred(struct net_device *dev, > >> + enum switchdev_notifier_type nt, > >> + const struct switchdev_obj *obj) > > > > A kernel-doc comment would be great. It looks like it's not returning > > whether the port object is deferred, but whether the _action_ given by > > @nt on the @obj is deferred. This further distinguishes between deferred > > additions and deferred removals. > > > > Fair, so should the name change as well? I guess you'd want something > like switchdev_port_obj_notification_is_deferred, but that sure is > awfully long. switchdev_port_obj_act_is_deferred() for action, maybe?
On Wed, Jan 31, 2024 at 01:50:11PM +0100, Jiri Pirko wrote: > Wed, Jan 31, 2024 at 01:35:43PM CET, tobias@waldekranz.com wrote: > >When adding/removing a port to/from a bridge, the port must be brought > >up to speed with the current state of the bridge. This is done by > >replaying all relevant events, directly to the port in question. > > Could you please use the imperative mood in your patch descriptions? > That way, it is much easier to understand what is the current state of > things and what you are actually changing. FWIW, the paragraph you've concentrated upon does describe the current state of things, not what the patch does; thus it does not need to be in the imperative mood.
Thu, Feb 01, 2024 at 01:33:05AM CET, olteanv@gmail.com wrote: >On Wed, Jan 31, 2024 at 01:50:11PM +0100, Jiri Pirko wrote: >> Wed, Jan 31, 2024 at 01:35:43PM CET, tobias@waldekranz.com wrote: >> >When adding/removing a port to/from a bridge, the port must be brought >> >up to speed with the current state of the bridge. This is done by >> >replaying all relevant events, directly to the port in question. >> >> Could you please use the imperative mood in your patch descriptions? >> That way, it is much easier to understand what is the current state of >> things and what you are actually changing. > >FWIW, the paragraph you've concentrated upon does describe the current >state of things, not what the patch does; thus it does not need to be in >the imperative mood. Well, there is no imperative mood in the next paragraph either :) Therefore from the patch desctiption pow now clue what the patch is doing.
diff --git a/include/net/switchdev.h b/include/net/switchdev.h index a43062d4c734..538851a93d9e 100644 --- a/include/net/switchdev.h +++ b/include/net/switchdev.h @@ -308,6 +308,9 @@ void switchdev_deferred_process(void); int switchdev_port_attr_set(struct net_device *dev, const struct switchdev_attr *attr, struct netlink_ext_ack *extack); +bool switchdev_port_obj_is_deferred(struct net_device *dev, + enum switchdev_notifier_type nt, + const struct switchdev_obj *obj); int switchdev_port_obj_add(struct net_device *dev, const struct switchdev_obj *obj, struct netlink_ext_ack *extack); diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c index 5b045284849e..40bb17c7fdbf 100644 --- a/net/switchdev/switchdev.c +++ b/net/switchdev/switchdev.c @@ -19,6 +19,35 @@ #include <linux/rtnetlink.h> #include <net/switchdev.h> +static bool switchdev_obj_eq(const struct switchdev_obj *a, + const struct switchdev_obj *b) +{ + const struct switchdev_obj_port_vlan *va, *vb; + const struct switchdev_obj_port_mdb *ma, *mb; + + if (a->id != b->id || a->orig_dev != b->orig_dev) + return false; + + switch (a->id) { + case SWITCHDEV_OBJ_ID_PORT_VLAN: + va = SWITCHDEV_OBJ_PORT_VLAN(a); + vb = SWITCHDEV_OBJ_PORT_VLAN(b); + return va->flags == vb->flags && + va->vid == vb->vid && + va->changed == vb->changed; + case SWITCHDEV_OBJ_ID_PORT_MDB: + case SWITCHDEV_OBJ_ID_HOST_MDB: + ma = SWITCHDEV_OBJ_PORT_MDB(a); + mb = SWITCHDEV_OBJ_PORT_MDB(b); + return ma->vid == mb->vid && + !memcmp(ma->addr, mb->addr, sizeof(ma->addr)); + default: + break; + } + + BUG(); +} + static LIST_HEAD(deferred); static DEFINE_SPINLOCK(deferred_lock); @@ -307,6 +336,38 @@ int switchdev_port_obj_del(struct net_device *dev, } EXPORT_SYMBOL_GPL(switchdev_port_obj_del); +bool switchdev_port_obj_is_deferred(struct net_device *dev, + enum switchdev_notifier_type nt, + const struct switchdev_obj *obj) +{ + struct switchdev_deferred_item *dfitem; + bool found = false; + + ASSERT_RTNL(); + + spin_lock_bh(&deferred_lock); + + list_for_each_entry(dfitem, &deferred, list) { + if (dfitem->dev != dev) + continue; + + if ((dfitem->func == switchdev_port_obj_add_deferred && + nt == SWITCHDEV_PORT_OBJ_ADD) || + (dfitem->func == switchdev_port_obj_del_deferred && + nt == SWITCHDEV_PORT_OBJ_DEL)) { + if (switchdev_obj_eq((const void *)dfitem->data, obj)) { + found = true; + break; + } + } + } + + spin_unlock_bh(&deferred_lock); + + return found; +} +EXPORT_SYMBOL_GPL(switchdev_port_obj_is_deferred); + static ATOMIC_NOTIFIER_HEAD(switchdev_notif_chain); static BLOCKING_NOTIFIER_HEAD(switchdev_blocking_notif_chain);
When adding/removing a port to/from a bridge, the port must be brought up to speed with the current state of the bridge. This is done by replaying all relevant events, directly to the port in question. In some situations, specifically when replaying the MDB, this process may race against new events that are generated concurrently. So the bridge must ensure that the event is not already pending on the deferred queue. switchdev_port_obj_is_deferred answers this question. Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> --- include/net/switchdev.h | 3 ++ net/switchdev/switchdev.c | 61 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 64 insertions(+)