diff options
Diffstat (limited to 'pkgs/patches-linux-5.15/701-net-dsa-make-tagging-protocols-connect-to-individual-switches.patch')
| -rw-r--r-- | pkgs/patches-linux-5.15/701-net-dsa-make-tagging-protocols-connect-to-individual-switches.patch | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/pkgs/patches-linux-5.15/701-net-dsa-make-tagging-protocols-connect-to-individual-switches.patch b/pkgs/patches-linux-5.15/701-net-dsa-make-tagging-protocols-connect-to-individual-switches.patch new file mode 100644 index 0000000..f682260 --- /dev/null +++ b/pkgs/patches-linux-5.15/701-net-dsa-make-tagging-protocols-connect-to-individual-switches.patch @@ -0,0 +1,274 @@ +From 7f2973149c22e7a6fee4c0c9fa6b8e4108e9c208 Mon Sep 17 00:00:00 2001 +From: Vladimir Oltean <vladimir.oltean@nxp.com> +Date: Tue, 14 Dec 2021 03:45:36 +0200 +Subject: net: dsa: make tagging protocols connect to individual switches from + a tree + +On the NXP Bluebox 3 board which uses a multi-switch setup with sja1105, +the mechanism through which the tagger connects to the switch tree is +broken, due to improper DSA code design. At the time when tag_ops->connect() +is called in dsa_port_parse_cpu(), DSA hasn't finished "touching" all +the ports, so it doesn't know how large the tree is and how many ports +it has. It has just seen the first CPU port by this time. As a result, +this function will call the tagger's ->connect method too early, and the +tagger will connect only to the first switch from the tree. + +This could be perhaps addressed a bit more simply by just moving the +tag_ops->connect(dst) call a bit later (for example in dsa_tree_setup), +but there is already a design inconsistency at present: on the switch +side, the notification is on a per-switch basis, but on the tagger side, +it is on a per-tree basis. Furthermore, the persistent storage itself is +per switch (ds->tagger_data). And the tagger connect and disconnect +procedures (at least the ones that exist currently) could see a fair bit +of simplification if they didn't have to iterate through the switches of +a tree. + +To fix the issue, this change transforms tag_ops->connect(dst) into +tag_ops->connect(ds) and moves it somewhere where we already iterate +over all switches of a tree. That is in dsa_switch_setup_tag_protocol(), +which is a good placement because we already have there the connection +call to the switch side of things. + +As for the dsa_tree_bind_tag_proto() method (called from the code path +that changes the tag protocol), things are a bit more complicated +because we receive the tree as argument, yet when we unwind on errors, +it would be nice to not call tag_ops->disconnect(ds) where we didn't +previously call tag_ops->connect(ds). We didn't have this problem before +because the tag_ops connection operations passed the entire dst before, +and this is more fine grained now. To solve the error rewind case using +the new API, we have to create yet one more cross-chip notifier for +disconnection, and stay connected with the old tag protocol to all the +switches in the tree until we've succeeded to connect with the new one +as well. So if something fails half way, the whole tree is still +connected to the old tagger. But there may still be leaks if the tagger +fails to connect to the 2nd out of 3 switches in a tree: somebody needs +to tell the tagger to disconnect from the first switch. Nothing comes +for free, and this was previously handled privately by the tagging +protocol driver before, but now we need to emit a disconnect cross-chip +notifier for that, because DSA has to take care of the unwind path. We +assume that the tagging protocol has connected to a switch if it has set +ds->tagger_data to something, otherwise we avoid calling its +disconnection method in the error rewind path. + +The rest of the changes are in the tagging protocol drivers, and have to +do with the replacement of dst with ds. The iteration is removed and the +error unwind path is simplified, as mentioned above. + +Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> +Signed-off-by: David S. Miller <davem@davemloft.net> +--- + include/net/dsa.h | 5 ++-- + net/dsa/dsa2.c | 44 +++++++++++++----------------- + net/dsa/dsa_priv.h | 1 + + net/dsa/switch.c | 52 ++++++++++++++++++++++++++++++++--- + net/dsa/tag_ocelot_8021q.c | 53 +++++++++++------------------------- + net/dsa/tag_sja1105.c | 67 ++++++++++++++++------------------------------ + 6 files changed, 109 insertions(+), 113 deletions(-) + +--- a/include/net/dsa.h ++++ b/include/net/dsa.h +@@ -80,15 +80,14 @@ enum dsa_tag_protocol { + }; + + struct dsa_switch; +-struct dsa_switch_tree; + + struct dsa_device_ops { + struct sk_buff *(*xmit)(struct sk_buff *skb, struct net_device *dev); + struct sk_buff *(*rcv)(struct sk_buff *skb, struct net_device *dev); + void (*flow_dissect)(const struct sk_buff *skb, __be16 *proto, + int *offset); +- int (*connect)(struct dsa_switch_tree *dst); +- void (*disconnect)(struct dsa_switch_tree *dst); ++ int (*connect)(struct dsa_switch *ds); ++ void (*disconnect)(struct dsa_switch *ds); + unsigned int needed_headroom; + unsigned int needed_tailroom; + const char *name; +--- a/net/dsa/dsa2.c ++++ b/net/dsa/dsa2.c +@@ -230,12 +230,8 @@ static struct dsa_switch_tree *dsa_tree_ + + static void dsa_tree_free(struct dsa_switch_tree *dst) + { +- if (dst->tag_ops) { +- if (dst->tag_ops->disconnect) +- dst->tag_ops->disconnect(dst); +- ++ if (dst->tag_ops) + dsa_tag_driver_put(dst->tag_ops); +- } + list_del(&dst->list); + kfree(dst); + } +@@ -826,17 +822,29 @@ static int dsa_switch_setup_tag_protocol + } + + connect: ++ if (tag_ops->connect) { ++ err = tag_ops->connect(ds); ++ if (err) ++ return err; ++ } ++ + if (ds->ops->connect_tag_protocol) { + err = ds->ops->connect_tag_protocol(ds, tag_ops->proto); + if (err) { + dev_err(ds->dev, + "Unable to connect to tag protocol \"%s\": %pe\n", + tag_ops->name, ERR_PTR(err)); +- return err; ++ goto disconnect; + } + } + + return 0; ++ ++disconnect: ++ if (tag_ops->disconnect) ++ tag_ops->disconnect(ds); ++ ++ return err; + } + + static int dsa_switch_setup(struct dsa_switch *ds) +@@ -1156,13 +1164,6 @@ static int dsa_tree_bind_tag_proto(struc + + dst->tag_ops = tag_ops; + +- /* Notify the new tagger about the connection to this tree */ +- if (tag_ops->connect) { +- err = tag_ops->connect(dst); +- if (err) +- goto out_revert; +- } +- + /* Notify the switches from this tree about the connection + * to the new tagger + */ +@@ -1172,16 +1173,14 @@ static int dsa_tree_bind_tag_proto(struc + goto out_disconnect; + + /* Notify the old tagger about the disconnection from this tree */ +- if (old_tag_ops->disconnect) +- old_tag_ops->disconnect(dst); ++ info.tag_ops = old_tag_ops; ++ dsa_tree_notify(dst, DSA_NOTIFIER_TAG_PROTO_DISCONNECT, &info); + + return 0; + + out_disconnect: +- /* Revert the new tagger's connection to this tree */ +- if (tag_ops->disconnect) +- tag_ops->disconnect(dst); +-out_revert: ++ info.tag_ops = tag_ops; ++ dsa_tree_notify(dst, DSA_NOTIFIER_TAG_PROTO_DISCONNECT, &info); + dst->tag_ops = old_tag_ops; + + return err; +@@ -1315,7 +1314,6 @@ static int dsa_port_parse_cpu(struct dsa + struct dsa_switch_tree *dst = ds->dst; + const struct dsa_device_ops *tag_ops; + enum dsa_tag_protocol default_proto; +- int err; + + /* Find out which protocol the switch would prefer. */ + default_proto = dsa_get_tag_protocol(dp, master); +@@ -1363,12 +1361,6 @@ static int dsa_port_parse_cpu(struct dsa + */ + dsa_tag_driver_put(tag_ops); + } else { +- if (tag_ops->connect) { +- err = tag_ops->connect(dst); +- if (err) +- return err; +- } +- + dst->tag_ops = tag_ops; + } + +--- a/net/dsa/dsa_priv.h ++++ b/net/dsa/dsa_priv.h +@@ -38,6 +38,7 @@ enum { + DSA_NOTIFIER_MTU, + DSA_NOTIFIER_TAG_PROTO, + DSA_NOTIFIER_TAG_PROTO_CONNECT, ++ DSA_NOTIFIER_TAG_PROTO_DISCONNECT, + DSA_NOTIFIER_MRP_ADD, + DSA_NOTIFIER_MRP_DEL, + DSA_NOTIFIER_MRP_ADD_RING_ROLE, +--- a/net/dsa/switch.c ++++ b/net/dsa/switch.c +@@ -616,15 +616,58 @@ static int dsa_switch_change_tag_proto(s + return 0; + } + +-static int dsa_switch_connect_tag_proto(struct dsa_switch *ds, +- struct dsa_notifier_tag_proto_info *info) ++/* We use the same cross-chip notifiers to inform both the tagger side, as well ++ * as the switch side, of connection and disconnection events. ++ * Since ds->tagger_data is owned by the tagger, it isn't a hard error if the ++ * switch side doesn't support connecting to this tagger, and therefore, the ++ * fact that we don't disconnect the tagger side doesn't constitute a memory ++ * leak: the tagger will still operate with persistent per-switch memory, just ++ * with the switch side unconnected to it. What does constitute a hard error is ++ * when the switch side supports connecting but fails. ++ */ ++static int ++dsa_switch_connect_tag_proto(struct dsa_switch *ds, ++ struct dsa_notifier_tag_proto_info *info) + { + const struct dsa_device_ops *tag_ops = info->tag_ops; ++ int err; ++ ++ /* Notify the new tagger about the connection to this switch */ ++ if (tag_ops->connect) { ++ err = tag_ops->connect(ds); ++ if (err) ++ return err; ++ } + + if (!ds->ops->connect_tag_protocol) + return -EOPNOTSUPP; + +- return ds->ops->connect_tag_protocol(ds, tag_ops->proto); ++ /* Notify the switch about the connection to the new tagger */ ++ err = ds->ops->connect_tag_protocol(ds, tag_ops->proto); ++ if (err) { ++ /* Revert the new tagger's connection to this tree */ ++ if (tag_ops->disconnect) ++ tag_ops->disconnect(ds); ++ return err; ++ } ++ ++ return 0; ++} ++ ++static int ++dsa_switch_disconnect_tag_proto(struct dsa_switch *ds, ++ struct dsa_notifier_tag_proto_info *info) ++{ ++ const struct dsa_device_ops *tag_ops = info->tag_ops; ++ ++ /* Notify the tagger about the disconnection from this switch */ ++ if (tag_ops->disconnect && ds->tagger_data) ++ tag_ops->disconnect(ds); ++ ++ /* No need to notify the switch, since it shouldn't have any ++ * resources to tear down ++ */ ++ return 0; + } + + static int dsa_switch_mrp_add(struct dsa_switch *ds, +@@ -749,6 +792,9 @@ static int dsa_switch_event(struct notif + case DSA_NOTIFIER_TAG_PROTO_CONNECT: + err = dsa_switch_connect_tag_proto(ds, info); + break; ++ case DSA_NOTIFIER_TAG_PROTO_DISCONNECT: ++ err = dsa_switch_disconnect_tag_proto(ds, info); ++ break; + case DSA_NOTIFIER_MRP_ADD: + err = dsa_switch_mrp_add(ds, info); + break; |