| Message ID | 5a6ba6f14b0fad6d4ba077a5230ee71cbf970934.1652819479.git.jtoppins@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [RFC,net-next] bonding: netlink error message support for options | expand |
Jonathan Toppins <jtoppins@redhat.com> wrote: >Add support for reporting errors via extack in both bond_newlink >and bond_changelink. > >Instead of having to look in the kernel log for why an option was not >correct just report the error to the user via the extack variable. > >What is currently reported today: > ip link add bond0 type bond > ip link set bond0 up > ip link set bond0 type bond mode 4 > RTNETLINK answers: Device or resource busy > >After this change: > ip link add bond0 type bond > ip link set bond0 up > ip link set bond0 type bond mode 4 > Error: option mode: unable to set because the bond device is up. > >Signed-off-by: Jonathan Toppins <jtoppins@redhat.com> >--- > >Notes: > This is an RFC because the current NL_SET_ERR_MSG() macros do not support > printf like semantics so I rolled my own buffer setting in __bond_opt_set(). > The issue is I could not quite figure out the life-cycle of the buffer, if > rtnl lock is held until after the text buffer is copied into the packet > then we are ok, otherwise, some other type of buffer management scheme will > be needed as this could result in corrupted error messages when modifying > multiple bonds. If I'm reading the code correctly, rtnl isn't held that long. Once the ->doit() returns, rtnl is dropped, but the copy happens later: rtnetlink_rcv() netlink_rcv_skb(skb, &rtnetlink_rcv_msg) rtnetlink_rcv_msg() [ as cb(skb, nlh, &extack) ] rtnl_lock() link->doit() [ rtnl_setlink, rtnl_newlink, et al ] rtnl_unlock() netlink_ack() inside netlink_ack(): if (nlk_has_extack && extack) { if (extack->_msg) { WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg)); } Even if the strings have to be constant (via NL_SET_ERR_MSG), adding extack messages is likely still an improvement. -J > drivers/net/bonding/bond_netlink.c | 87 ++++++++++++++++++------------ > drivers/net/bonding/bond_options.c | 62 +++++++++++++-------- > include/net/bond_options.h | 2 +- > 3 files changed, 96 insertions(+), 55 deletions(-) > >diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c >index f427fa1737c7..418a4f3d00a3 100644 >--- a/drivers/net/bonding/bond_netlink.c >+++ b/drivers/net/bonding/bond_netlink.c >@@ -151,7 +151,7 @@ static int bond_slave_changelink(struct net_device *bond_dev, > snprintf(queue_id_str, sizeof(queue_id_str), "%s:%u\n", > slave_dev->name, queue_id); > bond_opt_initstr(&newval, queue_id_str); >- err = __bond_opt_set(bond, BOND_OPT_QUEUE_ID, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_QUEUE_ID, &newval, extack); > if (err) > return err; > } >@@ -175,7 +175,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > int mode = nla_get_u8(data[IFLA_BOND_MODE]); > > bond_opt_initval(&newval, mode); >- err = __bond_opt_set(bond, BOND_OPT_MODE, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_MODE, &newval, extack); > if (err) > return err; > } >@@ -192,7 +192,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > active_slave = slave_dev->name; > } > bond_opt_initstr(&newval, active_slave); >- err = __bond_opt_set(bond, BOND_OPT_ACTIVE_SLAVE, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_ACTIVE_SLAVE, &newval, >+ extack); > if (err) > return err; > } >@@ -200,7 +201,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > miimon = nla_get_u32(data[IFLA_BOND_MIIMON]); > > bond_opt_initval(&newval, miimon); >- err = __bond_opt_set(bond, BOND_OPT_MIIMON, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_MIIMON, &newval, extack); > if (err) > return err; > } >@@ -208,7 +209,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > int updelay = nla_get_u32(data[IFLA_BOND_UPDELAY]); > > bond_opt_initval(&newval, updelay); >- err = __bond_opt_set(bond, BOND_OPT_UPDELAY, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_UPDELAY, &newval, extack); > if (err) > return err; > } >@@ -216,7 +217,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > int downdelay = nla_get_u32(data[IFLA_BOND_DOWNDELAY]); > > bond_opt_initval(&newval, downdelay); >- err = __bond_opt_set(bond, BOND_OPT_DOWNDELAY, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_DOWNDELAY, &newval, extack); > if (err) > return err; > } >@@ -224,7 +225,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > int delay = nla_get_u32(data[IFLA_BOND_PEER_NOTIF_DELAY]); > > bond_opt_initval(&newval, delay); >- err = __bond_opt_set(bond, BOND_OPT_PEER_NOTIF_DELAY, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_PEER_NOTIF_DELAY, &newval, >+ extack); > if (err) > return err; > } >@@ -232,7 +234,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > int use_carrier = nla_get_u8(data[IFLA_BOND_USE_CARRIER]); > > bond_opt_initval(&newval, use_carrier); >- err = __bond_opt_set(bond, BOND_OPT_USE_CARRIER, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_USE_CARRIER, &newval, >+ extack); > if (err) > return err; > } >@@ -240,12 +243,14 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > int arp_interval = nla_get_u32(data[IFLA_BOND_ARP_INTERVAL]); > > if (arp_interval && miimon) { >- netdev_err(bond->dev, "ARP monitoring cannot be used with MII monitoring\n"); >+ NL_SET_ERR_MSG(extack, >+ "ARP monitoring cannot be used with MII monitoring"); > return -EINVAL; > } > > bond_opt_initval(&newval, arp_interval); >- err = __bond_opt_set(bond, BOND_OPT_ARP_INTERVAL, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_ARP_INTERVAL, &newval, >+ extack); > if (err) > return err; > } >@@ -264,7 +269,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > > bond_opt_initval(&newval, (__force u64)target); > err = __bond_opt_set(bond, BOND_OPT_ARP_TARGETS, >- &newval); >+ &newval, extack); > if (err) > break; > i++; >@@ -297,7 +302,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > > bond_opt_initextra(&newval, &addr6, sizeof(addr6)); > err = __bond_opt_set(bond, BOND_OPT_NS_TARGETS, >- &newval); >+ &newval, extack); > if (err) > break; > i++; >@@ -312,12 +317,14 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > int arp_validate = nla_get_u32(data[IFLA_BOND_ARP_VALIDATE]); > > if (arp_validate && miimon) { >- netdev_err(bond->dev, "ARP validating cannot be used with MII monitoring\n"); >+ NL_SET_ERR_MSG(extack, >+ "ARP validating cannot be used with MII monitoring"); > return -EINVAL; > } > > bond_opt_initval(&newval, arp_validate); >- err = __bond_opt_set(bond, BOND_OPT_ARP_VALIDATE, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_ARP_VALIDATE, &newval, >+ extack); > if (err) > return err; > } >@@ -326,7 +333,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u32(data[IFLA_BOND_ARP_ALL_TARGETS]); > > bond_opt_initval(&newval, arp_all_targets); >- err = __bond_opt_set(bond, BOND_OPT_ARP_ALL_TARGETS, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_ARP_ALL_TARGETS, &newval, >+ extack); > if (err) > return err; > } >@@ -340,7 +348,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > primary = dev->name; > > bond_opt_initstr(&newval, primary); >- err = __bond_opt_set(bond, BOND_OPT_PRIMARY, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_PRIMARY, &newval, extack); > if (err) > return err; > } >@@ -349,7 +357,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u8(data[IFLA_BOND_PRIMARY_RESELECT]); > > bond_opt_initval(&newval, primary_reselect); >- err = __bond_opt_set(bond, BOND_OPT_PRIMARY_RESELECT, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_PRIMARY_RESELECT, &newval, >+ extack); > if (err) > return err; > } >@@ -358,7 +367,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u8(data[IFLA_BOND_FAIL_OVER_MAC]); > > bond_opt_initval(&newval, fail_over_mac); >- err = __bond_opt_set(bond, BOND_OPT_FAIL_OVER_MAC, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_FAIL_OVER_MAC, &newval, >+ extack); > if (err) > return err; > } >@@ -367,7 +377,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u8(data[IFLA_BOND_XMIT_HASH_POLICY]); > > bond_opt_initval(&newval, xmit_hash_policy); >- err = __bond_opt_set(bond, BOND_OPT_XMIT_HASH, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_XMIT_HASH, &newval, extack); > if (err) > return err; > } >@@ -376,7 +386,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u32(data[IFLA_BOND_RESEND_IGMP]); > > bond_opt_initval(&newval, resend_igmp); >- err = __bond_opt_set(bond, BOND_OPT_RESEND_IGMP, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_RESEND_IGMP, &newval, >+ extack); > if (err) > return err; > } >@@ -385,7 +396,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u8(data[IFLA_BOND_NUM_PEER_NOTIF]); > > bond_opt_initval(&newval, num_peer_notif); >- err = __bond_opt_set(bond, BOND_OPT_NUM_PEER_NOTIF, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_NUM_PEER_NOTIF, &newval, >+ extack); > if (err) > return err; > } >@@ -394,7 +406,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u8(data[IFLA_BOND_ALL_SLAVES_ACTIVE]); > > bond_opt_initval(&newval, all_slaves_active); >- err = __bond_opt_set(bond, BOND_OPT_ALL_SLAVES_ACTIVE, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_ALL_SLAVES_ACTIVE, &newval, >+ extack); > if (err) > return err; > } >@@ -403,7 +416,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u32(data[IFLA_BOND_MIN_LINKS]); > > bond_opt_initval(&newval, min_links); >- err = __bond_opt_set(bond, BOND_OPT_MINLINKS, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_MINLINKS, &newval, extack); > if (err) > return err; > } >@@ -412,7 +425,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u32(data[IFLA_BOND_LP_INTERVAL]); > > bond_opt_initval(&newval, lp_interval); >- err = __bond_opt_set(bond, BOND_OPT_LP_INTERVAL, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_LP_INTERVAL, &newval, >+ extack); > if (err) > return err; > } >@@ -421,7 +435,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u32(data[IFLA_BOND_PACKETS_PER_SLAVE]); > > bond_opt_initval(&newval, packets_per_slave); >- err = __bond_opt_set(bond, BOND_OPT_PACKETS_PER_SLAVE, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_PACKETS_PER_SLAVE, &newval, >+ extack); > if (err) > return err; > } >@@ -430,7 +445,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > int lacp_active = nla_get_u8(data[IFLA_BOND_AD_LACP_ACTIVE]); > > bond_opt_initval(&newval, lacp_active); >- err = __bond_opt_set(bond, BOND_OPT_LACP_ACTIVE, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_LACP_ACTIVE, &newval, >+ extack); > if (err) > return err; > } >@@ -440,7 +456,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u8(data[IFLA_BOND_AD_LACP_RATE]); > > bond_opt_initval(&newval, lacp_rate); >- err = __bond_opt_set(bond, BOND_OPT_LACP_RATE, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_LACP_RATE, &newval, extack); > if (err) > return err; > } >@@ -449,7 +465,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u8(data[IFLA_BOND_AD_SELECT]); > > bond_opt_initval(&newval, ad_select); >- err = __bond_opt_set(bond, BOND_OPT_AD_SELECT, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_AD_SELECT, &newval, extack); > if (err) > return err; > } >@@ -458,7 +474,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u16(data[IFLA_BOND_AD_ACTOR_SYS_PRIO]); > > bond_opt_initval(&newval, actor_sys_prio); >- err = __bond_opt_set(bond, BOND_OPT_AD_ACTOR_SYS_PRIO, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_AD_ACTOR_SYS_PRIO, &newval, >+ extack); > if (err) > return err; > } >@@ -467,7 +484,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > nla_get_u16(data[IFLA_BOND_AD_USER_PORT_KEY]); > > bond_opt_initval(&newval, port_key); >- err = __bond_opt_set(bond, BOND_OPT_AD_USER_PORT_KEY, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_AD_USER_PORT_KEY, &newval, >+ extack); > if (err) > return err; > } >@@ -477,7 +495,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > > bond_opt_initval(&newval, > nla_get_u64(data[IFLA_BOND_AD_ACTOR_SYSTEM])); >- err = __bond_opt_set(bond, BOND_OPT_AD_ACTOR_SYSTEM, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_AD_ACTOR_SYSTEM, &newval, >+ extack); > if (err) > return err; > } >@@ -485,7 +504,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > int dynamic_lb = nla_get_u8(data[IFLA_BOND_TLB_DYNAMIC_LB]); > > bond_opt_initval(&newval, dynamic_lb); >- err = __bond_opt_set(bond, BOND_OPT_TLB_DYNAMIC_LB, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_TLB_DYNAMIC_LB, &newval, >+ extack); > if (err) > return err; > } >@@ -494,7 +514,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], > int missed_max = nla_get_u8(data[IFLA_BOND_MISSED_MAX]); > > bond_opt_initval(&newval, missed_max); >- err = __bond_opt_set(bond, BOND_OPT_MISSED_MAX, &newval); >+ err = __bond_opt_set(bond, BOND_OPT_MISSED_MAX, &newval, >+ extack); > if (err) > return err; > } >diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c >index 64f7db2627ce..4a95503384a3 100644 >--- a/drivers/net/bonding/bond_options.c >+++ b/drivers/net/bonding/bond_options.c >@@ -636,7 +636,8 @@ static int bond_opt_check_deps(struct bonding *bond, > } > > static void bond_opt_dep_print(struct bonding *bond, >- const struct bond_option *opt) >+ const struct bond_option *opt, >+ char *buf, size_t bufsize) > { > const struct bond_opt_value *modeval; > struct bond_params *params; >@@ -644,16 +645,18 @@ static void bond_opt_dep_print(struct bonding *bond, > params = &bond->params; > modeval = bond_opt_get_val(BOND_OPT_MODE, params->mode); > if (test_bit(params->mode, &opt->unsuppmodes)) >- netdev_err(bond->dev, "option %s: mode dependency failed, not supported in mode %s(%llu)\n", >- opt->name, modeval->string, modeval->value); >+ scnprintf(buf, bufsize, "option %s: mode dependency failed, not supported in mode %s(%llu)\n", >+ opt->name, modeval->string, modeval->value); > } > > static void bond_opt_error_interpret(struct bonding *bond, > const struct bond_option *opt, >- int error, const struct bond_opt_value *val) >+ int error, const struct bond_opt_value *val, >+ char *buf, size_t bufsize) > { > const struct bond_opt_value *minval, *maxval; > char *p; >+ int i = 0; > > switch (error) { > case -EINVAL: >@@ -663,38 +666,45 @@ static void bond_opt_error_interpret(struct bonding *bond, > p = strchr(val->string, '\n'); > if (p) > *p = '\0'; >- netdev_err(bond->dev, "option %s: invalid value (%s)\n", >- opt->name, val->string); >+ i = scnprintf(buf, bufsize, >+ "option %s: invalid value (%s)", >+ opt->name, val->string); > } else { >- netdev_err(bond->dev, "option %s: invalid value (%llu)\n", >- opt->name, val->value); >+ i = scnprintf(buf, bufsize, >+ "option %s: invalid value (%llu)", >+ opt->name, val->value); > } > } > minval = bond_opt_get_flags(opt, BOND_VALFLAG_MIN); > maxval = bond_opt_get_flags(opt, BOND_VALFLAG_MAX); > if (!maxval) > break; >- netdev_err(bond->dev, "option %s: allowed values %llu - %llu\n", >- opt->name, minval ? minval->value : 0, maxval->value); >+ if (i) { >+ // index buf to overwirte '\n' from above >+ buf = &buf[i]; >+ bufsize -= i; >+ } >+ scnprintf(buf, bufsize, " allowed values %llu - %llu", >+ minval ? minval->value : 0, maxval->value); > break; > case -EACCES: >- bond_opt_dep_print(bond, opt); >+ bond_opt_dep_print(bond, opt, buf, bufsize); > break; > case -ENOTEMPTY: >- netdev_err(bond->dev, "option %s: unable to set because the bond device has slaves\n", >- opt->name); >+ scnprintf(buf, bufsize, "option %s: unable to set because the bond device has slaves", >+ opt->name); > break; > case -EBUSY: >- netdev_err(bond->dev, "option %s: unable to set because the bond device is up\n", >- opt->name); >+ scnprintf(buf, bufsize, "option %s: unable to set because the bond device is up", >+ opt->name); > break; > case -ENODEV: > if (val && val->string) { > p = strchr(val->string, '\n'); > if (p) > *p = '\0'; >- netdev_err(bond->dev, "option %s: interface %s does not exist!\n", >- opt->name, val->string); >+ scnprintf(buf, bufsize, "option %s: interface %s does not exist!", >+ opt->name, val->string); > } > break; > default: >@@ -713,7 +723,8 @@ static void bond_opt_error_interpret(struct bonding *bond, > * must be obtained before calling this function. > */ > int __bond_opt_set(struct bonding *bond, >- unsigned int option, struct bond_opt_value *val) >+ unsigned int option, struct bond_opt_value *val, >+ struct netlink_ext_ack *extack) > { > const struct bond_opt_value *retval = NULL; > const struct bond_option *opt; >@@ -734,8 +745,17 @@ int __bond_opt_set(struct bonding *bond, > } > ret = opt->set(bond, retval); > out: >- if (ret) >- bond_opt_error_interpret(bond, opt, ret, val); >+ if (ret) { >+ static char buf[120]; >+ buf[0] = '\0'; >+ bond_opt_error_interpret(bond, opt, ret, val, buf, sizeof(buf)); >+ if (buf[0] != '\0') { >+ if (extack) >+ extack->_msg = buf; >+ else >+ netdev_err(bond->dev, "Error: %s\n", buf); >+ } >+ } > > return ret; > } >@@ -757,7 +777,7 @@ int __bond_opt_set_notify(struct bonding *bond, > > ASSERT_RTNL(); > >- ret = __bond_opt_set(bond, option, val); >+ ret = __bond_opt_set(bond, option, val, NULL); > > if (!ret && (bond->dev->reg_state == NETREG_REGISTERED)) > call_netdevice_notifiers(NETDEV_CHANGEINFODATA, bond->dev); >diff --git a/include/net/bond_options.h b/include/net/bond_options.h >index 61b49063791c..ae38557adc25 100644 >--- a/include/net/bond_options.h >+++ b/include/net/bond_options.h >@@ -107,7 +107,7 @@ struct bond_option { > }; > > int __bond_opt_set(struct bonding *bond, unsigned int option, >- struct bond_opt_value *val); >+ struct bond_opt_value *val, struct netlink_ext_ack *extack); > int __bond_opt_set_notify(struct bonding *bond, unsigned int option, > struct bond_opt_value *val); > int bond_opt_tryset_rtnl(struct bonding *bond, unsigned int option, char *buf); >-- >2.27.0 > --- -Jay Vosburgh, jay.vosburgh@canonical.com
On Tue, 17 May 2022 14:11:14 -0700 Jay Vosburgh wrote: > If I'm reading the code correctly, rtnl isn't held that long. > Once the ->doit() returns, rtnl is dropped, but the copy happens later: > > rtnetlink_rcv() > netlink_rcv_skb(skb, &rtnetlink_rcv_msg) > rtnetlink_rcv_msg() [ as cb(skb, nlh, &extack) ] > rtnl_lock() > link->doit() [ rtnl_setlink, rtnl_newlink, et al ] > rtnl_unlock() > netlink_ack() > > inside netlink_ack(): > > if (nlk_has_extack && extack) { > if (extack->_msg) { > WARN_ON(nla_put_string(skb, NLMSGERR_ATTR_MSG, > extack->_msg)); > } Indeed. > Even if the strings have to be constant (via NL_SET_ERR_MSG), > adding extack messages is likely still an improvement. At a quick glance it seems like the major use of the printf here is to point at a particular option. If options are carried in individual attributes pointing at the right attribute with NL_SET_ERR_MSG_ATTR() should also be helpful. Maybe that's stating the obvious.
On Tue, 17 May 2022 16:31:19 -0400 Jonathan Toppins <jtoppins@redhat.com> wrote: > This is an RFC because the current NL_SET_ERR_MSG() macros do not support > printf like semantics so I rolled my own buffer setting in __bond_opt_set(). > The issue is I could not quite figure out the life-cycle of the buffer, if > rtnl lock is held until after the text buffer is copied into the packet > then we are ok, otherwise, some other type of buffer management scheme will > be needed as this could result in corrupted error messages when modifying > multiple bonds. Might be better for others in long term if NL_SET_ERR_MSG() had printf like semantics. Surely this isn't going to be first or last case. Then internally, it could print right to the netlink message.
On Tue, 17 May 2022 15:44:19 -0700 Stephen Hemminger wrote: > On Tue, 17 May 2022 16:31:19 -0400 > Jonathan Toppins <jtoppins@redhat.com> wrote: > > > This is an RFC because the current NL_SET_ERR_MSG() macros do not support > > printf like semantics so I rolled my own buffer setting in __bond_opt_set(). > > The issue is I could not quite figure out the life-cycle of the buffer, if > > rtnl lock is held until after the text buffer is copied into the packet > > then we are ok, otherwise, some other type of buffer management scheme will > > be needed as this could result in corrupted error messages when modifying > > multiple bonds. > > Might be better for others in long term if NL_SET_ERR_MSG() had printf like > semantics. Surely this isn't going to be first or last case. > > Then internally, it could print right to the netlink message. Dunno. I think pointing at the bad attr + exposing per-attr netlink parsing policy + a string for a human worked pretty well so far. IMHO printf() is just a knee jerk reaction, especially when converting from netdev_err(). Augmenting structured information is much, much better long term. To me the never ending stream of efforts to improve printk() is a proof that once we let people printf() at will, efforts to contain it will be futile.
On 5/17/22 19:54, Jakub Kicinski wrote: > On Tue, 17 May 2022 15:44:19 -0700 Stephen Hemminger wrote: >> On Tue, 17 May 2022 16:31:19 -0400 >> Jonathan Toppins <jtoppins@redhat.com> wrote: >> >>> This is an RFC because the current NL_SET_ERR_MSG() macros do not support >>> printf like semantics so I rolled my own buffer setting in __bond_opt_set(). >>> The issue is I could not quite figure out the life-cycle of the buffer, if >>> rtnl lock is held until after the text buffer is copied into the packet >>> then we are ok, otherwise, some other type of buffer management scheme will >>> be needed as this could result in corrupted error messages when modifying >>> multiple bonds. >> >> Might be better for others in long term if NL_SET_ERR_MSG() had printf like >> semantics. Surely this isn't going to be first or last case. >> >> Then internally, it could print right to the netlink message. > > Dunno. I think pointing at the bad attr + exposing per-attr netlink > parsing policy + a string for a human worked pretty well so far. > IMHO printf() is just a knee jerk reaction, especially when converting > from netdev_err(). For some subsystems it is not a convert from netdev_err, it is an AND. In this RFC there are instances where changing the message from netdev_err() to the macro was trivial; @@ -240,12 +243,14 @@ static int bond_changelink(struct net_device *bond_dev, st ruct nlattr *tb[], int arp_interval = nla_get_u32(data[IFLA_BOND_ARP_INTERVAL]); if (arp_interval && miimon) { - netdev_err(bond->dev, "ARP monitoring cannot be used with MII monitoring\n"); + NL_SET_ERR_MSG(extack, + "ARP monitoring cannot be used with MII monitoring"); return -EINVAL; } These are trivial because the path does not have to care about sysfs or some other legacy configuration interface. These macros become rather annoying to use once a system needs to support multiple configuration paths and is trying to utilize as much common configuration code[0] as possible so that all interfaces largely operate the same way. > > Augmenting structured information is much, much better long term. > > To me the never ending stream of efforts to improve printk() is a > proof that once we let people printf() at will, efforts to contain > it will be futile. > At least for bonding I was trying to reuse the most amount of code which needs to deal with both sysfs and netlink. And I don't think it is a good idea to split the code paths, so if I am suppose to use statically allocated strings to support netlink errors that basically means anything that has to support multiple interfaces gets to sprinkle `if (extack)` everywhere[0]. Not great. The ownership model of the error buffer seems odd to me with the current macros, I am suppose to set a pointer in a structure subsystem X didn't allocate and has no control over its lifetime. Then netlink takes this pointer and does whatever with it. And somehow subsystem X is suppose to guarantee the pointer's lifetime exists forever, making a `const static char[]` buffer the only option. I don't understand why netlink doesn't provide the buffer and a subsystem just populates it. Using memcpy or snprintf doesn't matter, to me its a lifetime issue that makes the API not great to work with when you have to handle cases other than netlink. Also as Joe Perches points out in this thread[1,2] the way the macros are written it is bloating the kernel because the error messages are getting duplicated for subsystems that need to support multiple configuration interfaces. -Jon [0] https://lore.kernel.org/netdev/e6b78ce8f5904a5411a809cf4205d745f8af98cb.1628650079.git.jtoppins@redhat.com/ [1] https://lore.kernel.org/netdev/cover.1628306392.git.jtoppins@redhat.com/ [2] https://lore.kernel.org/netdev/c8b69905c995ab887633ef11862705ee66c60aad.camel@perches.com/
diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c index f427fa1737c7..418a4f3d00a3 100644 --- a/drivers/net/bonding/bond_netlink.c +++ b/drivers/net/bonding/bond_netlink.c @@ -151,7 +151,7 @@ static int bond_slave_changelink(struct net_device *bond_dev, snprintf(queue_id_str, sizeof(queue_id_str), "%s:%u\n", slave_dev->name, queue_id); bond_opt_initstr(&newval, queue_id_str); - err = __bond_opt_set(bond, BOND_OPT_QUEUE_ID, &newval); + err = __bond_opt_set(bond, BOND_OPT_QUEUE_ID, &newval, extack); if (err) return err; } @@ -175,7 +175,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], int mode = nla_get_u8(data[IFLA_BOND_MODE]); bond_opt_initval(&newval, mode); - err = __bond_opt_set(bond, BOND_OPT_MODE, &newval); + err = __bond_opt_set(bond, BOND_OPT_MODE, &newval, extack); if (err) return err; } @@ -192,7 +192,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], active_slave = slave_dev->name; } bond_opt_initstr(&newval, active_slave); - err = __bond_opt_set(bond, BOND_OPT_ACTIVE_SLAVE, &newval); + err = __bond_opt_set(bond, BOND_OPT_ACTIVE_SLAVE, &newval, + extack); if (err) return err; } @@ -200,7 +201,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], miimon = nla_get_u32(data[IFLA_BOND_MIIMON]); bond_opt_initval(&newval, miimon); - err = __bond_opt_set(bond, BOND_OPT_MIIMON, &newval); + err = __bond_opt_set(bond, BOND_OPT_MIIMON, &newval, extack); if (err) return err; } @@ -208,7 +209,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], int updelay = nla_get_u32(data[IFLA_BOND_UPDELAY]); bond_opt_initval(&newval, updelay); - err = __bond_opt_set(bond, BOND_OPT_UPDELAY, &newval); + err = __bond_opt_set(bond, BOND_OPT_UPDELAY, &newval, extack); if (err) return err; } @@ -216,7 +217,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], int downdelay = nla_get_u32(data[IFLA_BOND_DOWNDELAY]); bond_opt_initval(&newval, downdelay); - err = __bond_opt_set(bond, BOND_OPT_DOWNDELAY, &newval); + err = __bond_opt_set(bond, BOND_OPT_DOWNDELAY, &newval, extack); if (err) return err; } @@ -224,7 +225,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], int delay = nla_get_u32(data[IFLA_BOND_PEER_NOTIF_DELAY]); bond_opt_initval(&newval, delay); - err = __bond_opt_set(bond, BOND_OPT_PEER_NOTIF_DELAY, &newval); + err = __bond_opt_set(bond, BOND_OPT_PEER_NOTIF_DELAY, &newval, + extack); if (err) return err; } @@ -232,7 +234,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], int use_carrier = nla_get_u8(data[IFLA_BOND_USE_CARRIER]); bond_opt_initval(&newval, use_carrier); - err = __bond_opt_set(bond, BOND_OPT_USE_CARRIER, &newval); + err = __bond_opt_set(bond, BOND_OPT_USE_CARRIER, &newval, + extack); if (err) return err; } @@ -240,12 +243,14 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], int arp_interval = nla_get_u32(data[IFLA_BOND_ARP_INTERVAL]); if (arp_interval && miimon) { - netdev_err(bond->dev, "ARP monitoring cannot be used with MII monitoring\n"); + NL_SET_ERR_MSG(extack, + "ARP monitoring cannot be used with MII monitoring"); return -EINVAL; } bond_opt_initval(&newval, arp_interval); - err = __bond_opt_set(bond, BOND_OPT_ARP_INTERVAL, &newval); + err = __bond_opt_set(bond, BOND_OPT_ARP_INTERVAL, &newval, + extack); if (err) return err; } @@ -264,7 +269,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], bond_opt_initval(&newval, (__force u64)target); err = __bond_opt_set(bond, BOND_OPT_ARP_TARGETS, - &newval); + &newval, extack); if (err) break; i++; @@ -297,7 +302,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], bond_opt_initextra(&newval, &addr6, sizeof(addr6)); err = __bond_opt_set(bond, BOND_OPT_NS_TARGETS, - &newval); + &newval, extack); if (err) break; i++; @@ -312,12 +317,14 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], int arp_validate = nla_get_u32(data[IFLA_BOND_ARP_VALIDATE]); if (arp_validate && miimon) { - netdev_err(bond->dev, "ARP validating cannot be used with MII monitoring\n"); + NL_SET_ERR_MSG(extack, + "ARP validating cannot be used with MII monitoring"); return -EINVAL; } bond_opt_initval(&newval, arp_validate); - err = __bond_opt_set(bond, BOND_OPT_ARP_VALIDATE, &newval); + err = __bond_opt_set(bond, BOND_OPT_ARP_VALIDATE, &newval, + extack); if (err) return err; } @@ -326,7 +333,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u32(data[IFLA_BOND_ARP_ALL_TARGETS]); bond_opt_initval(&newval, arp_all_targets); - err = __bond_opt_set(bond, BOND_OPT_ARP_ALL_TARGETS, &newval); + err = __bond_opt_set(bond, BOND_OPT_ARP_ALL_TARGETS, &newval, + extack); if (err) return err; } @@ -340,7 +348,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], primary = dev->name; bond_opt_initstr(&newval, primary); - err = __bond_opt_set(bond, BOND_OPT_PRIMARY, &newval); + err = __bond_opt_set(bond, BOND_OPT_PRIMARY, &newval, extack); if (err) return err; } @@ -349,7 +357,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u8(data[IFLA_BOND_PRIMARY_RESELECT]); bond_opt_initval(&newval, primary_reselect); - err = __bond_opt_set(bond, BOND_OPT_PRIMARY_RESELECT, &newval); + err = __bond_opt_set(bond, BOND_OPT_PRIMARY_RESELECT, &newval, + extack); if (err) return err; } @@ -358,7 +367,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u8(data[IFLA_BOND_FAIL_OVER_MAC]); bond_opt_initval(&newval, fail_over_mac); - err = __bond_opt_set(bond, BOND_OPT_FAIL_OVER_MAC, &newval); + err = __bond_opt_set(bond, BOND_OPT_FAIL_OVER_MAC, &newval, + extack); if (err) return err; } @@ -367,7 +377,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u8(data[IFLA_BOND_XMIT_HASH_POLICY]); bond_opt_initval(&newval, xmit_hash_policy); - err = __bond_opt_set(bond, BOND_OPT_XMIT_HASH, &newval); + err = __bond_opt_set(bond, BOND_OPT_XMIT_HASH, &newval, extack); if (err) return err; } @@ -376,7 +386,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u32(data[IFLA_BOND_RESEND_IGMP]); bond_opt_initval(&newval, resend_igmp); - err = __bond_opt_set(bond, BOND_OPT_RESEND_IGMP, &newval); + err = __bond_opt_set(bond, BOND_OPT_RESEND_IGMP, &newval, + extack); if (err) return err; } @@ -385,7 +396,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u8(data[IFLA_BOND_NUM_PEER_NOTIF]); bond_opt_initval(&newval, num_peer_notif); - err = __bond_opt_set(bond, BOND_OPT_NUM_PEER_NOTIF, &newval); + err = __bond_opt_set(bond, BOND_OPT_NUM_PEER_NOTIF, &newval, + extack); if (err) return err; } @@ -394,7 +406,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u8(data[IFLA_BOND_ALL_SLAVES_ACTIVE]); bond_opt_initval(&newval, all_slaves_active); - err = __bond_opt_set(bond, BOND_OPT_ALL_SLAVES_ACTIVE, &newval); + err = __bond_opt_set(bond, BOND_OPT_ALL_SLAVES_ACTIVE, &newval, + extack); if (err) return err; } @@ -403,7 +416,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u32(data[IFLA_BOND_MIN_LINKS]); bond_opt_initval(&newval, min_links); - err = __bond_opt_set(bond, BOND_OPT_MINLINKS, &newval); + err = __bond_opt_set(bond, BOND_OPT_MINLINKS, &newval, extack); if (err) return err; } @@ -412,7 +425,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u32(data[IFLA_BOND_LP_INTERVAL]); bond_opt_initval(&newval, lp_interval); - err = __bond_opt_set(bond, BOND_OPT_LP_INTERVAL, &newval); + err = __bond_opt_set(bond, BOND_OPT_LP_INTERVAL, &newval, + extack); if (err) return err; } @@ -421,7 +435,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u32(data[IFLA_BOND_PACKETS_PER_SLAVE]); bond_opt_initval(&newval, packets_per_slave); - err = __bond_opt_set(bond, BOND_OPT_PACKETS_PER_SLAVE, &newval); + err = __bond_opt_set(bond, BOND_OPT_PACKETS_PER_SLAVE, &newval, + extack); if (err) return err; } @@ -430,7 +445,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], int lacp_active = nla_get_u8(data[IFLA_BOND_AD_LACP_ACTIVE]); bond_opt_initval(&newval, lacp_active); - err = __bond_opt_set(bond, BOND_OPT_LACP_ACTIVE, &newval); + err = __bond_opt_set(bond, BOND_OPT_LACP_ACTIVE, &newval, + extack); if (err) return err; } @@ -440,7 +456,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u8(data[IFLA_BOND_AD_LACP_RATE]); bond_opt_initval(&newval, lacp_rate); - err = __bond_opt_set(bond, BOND_OPT_LACP_RATE, &newval); + err = __bond_opt_set(bond, BOND_OPT_LACP_RATE, &newval, extack); if (err) return err; } @@ -449,7 +465,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u8(data[IFLA_BOND_AD_SELECT]); bond_opt_initval(&newval, ad_select); - err = __bond_opt_set(bond, BOND_OPT_AD_SELECT, &newval); + err = __bond_opt_set(bond, BOND_OPT_AD_SELECT, &newval, extack); if (err) return err; } @@ -458,7 +474,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u16(data[IFLA_BOND_AD_ACTOR_SYS_PRIO]); bond_opt_initval(&newval, actor_sys_prio); - err = __bond_opt_set(bond, BOND_OPT_AD_ACTOR_SYS_PRIO, &newval); + err = __bond_opt_set(bond, BOND_OPT_AD_ACTOR_SYS_PRIO, &newval, + extack); if (err) return err; } @@ -467,7 +484,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], nla_get_u16(data[IFLA_BOND_AD_USER_PORT_KEY]); bond_opt_initval(&newval, port_key); - err = __bond_opt_set(bond, BOND_OPT_AD_USER_PORT_KEY, &newval); + err = __bond_opt_set(bond, BOND_OPT_AD_USER_PORT_KEY, &newval, + extack); if (err) return err; } @@ -477,7 +495,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], bond_opt_initval(&newval, nla_get_u64(data[IFLA_BOND_AD_ACTOR_SYSTEM])); - err = __bond_opt_set(bond, BOND_OPT_AD_ACTOR_SYSTEM, &newval); + err = __bond_opt_set(bond, BOND_OPT_AD_ACTOR_SYSTEM, &newval, + extack); if (err) return err; } @@ -485,7 +504,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], int dynamic_lb = nla_get_u8(data[IFLA_BOND_TLB_DYNAMIC_LB]); bond_opt_initval(&newval, dynamic_lb); - err = __bond_opt_set(bond, BOND_OPT_TLB_DYNAMIC_LB, &newval); + err = __bond_opt_set(bond, BOND_OPT_TLB_DYNAMIC_LB, &newval, + extack); if (err) return err; } @@ -494,7 +514,8 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], int missed_max = nla_get_u8(data[IFLA_BOND_MISSED_MAX]); bond_opt_initval(&newval, missed_max); - err = __bond_opt_set(bond, BOND_OPT_MISSED_MAX, &newval); + err = __bond_opt_set(bond, BOND_OPT_MISSED_MAX, &newval, + extack); if (err) return err; } diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c index 64f7db2627ce..4a95503384a3 100644 --- a/drivers/net/bonding/bond_options.c +++ b/drivers/net/bonding/bond_options.c @@ -636,7 +636,8 @@ static int bond_opt_check_deps(struct bonding *bond, } static void bond_opt_dep_print(struct bonding *bond, - const struct bond_option *opt) + const struct bond_option *opt, + char *buf, size_t bufsize) { const struct bond_opt_value *modeval; struct bond_params *params; @@ -644,16 +645,18 @@ static void bond_opt_dep_print(struct bonding *bond, params = &bond->params; modeval = bond_opt_get_val(BOND_OPT_MODE, params->mode); if (test_bit(params->mode, &opt->unsuppmodes)) - netdev_err(bond->dev, "option %s: mode dependency failed, not supported in mode %s(%llu)\n", - opt->name, modeval->string, modeval->value); + scnprintf(buf, bufsize, "option %s: mode dependency failed, not supported in mode %s(%llu)\n", + opt->name, modeval->string, modeval->value); } static void bond_opt_error_interpret(struct bonding *bond, const struct bond_option *opt, - int error, const struct bond_opt_value *val) + int error, const struct bond_opt_value *val, + char *buf, size_t bufsize) { const struct bond_opt_value *minval, *maxval; char *p; + int i = 0; switch (error) { case -EINVAL: @@ -663,38 +666,45 @@ static void bond_opt_error_interpret(struct bonding *bond, p = strchr(val->string, '\n'); if (p) *p = '\0'; - netdev_err(bond->dev, "option %s: invalid value (%s)\n", - opt->name, val->string); + i = scnprintf(buf, bufsize, + "option %s: invalid value (%s)", + opt->name, val->string); } else { - netdev_err(bond->dev, "option %s: invalid value (%llu)\n", - opt->name, val->value); + i = scnprintf(buf, bufsize, + "option %s: invalid value (%llu)", + opt->name, val->value); } } minval = bond_opt_get_flags(opt, BOND_VALFLAG_MIN); maxval = bond_opt_get_flags(opt, BOND_VALFLAG_MAX); if (!maxval) break; - netdev_err(bond->dev, "option %s: allowed values %llu - %llu\n", - opt->name, minval ? minval->value : 0, maxval->value); + if (i) { + // index buf to overwirte '\n' from above + buf = &buf[i]; + bufsize -= i; + } + scnprintf(buf, bufsize, " allowed values %llu - %llu", + minval ? minval->value : 0, maxval->value); break; case -EACCES: - bond_opt_dep_print(bond, opt); + bond_opt_dep_print(bond, opt, buf, bufsize); break; case -ENOTEMPTY: - netdev_err(bond->dev, "option %s: unable to set because the bond device has slaves\n", - opt->name); + scnprintf(buf, bufsize, "option %s: unable to set because the bond device has slaves", + opt->name); break; case -EBUSY: - netdev_err(bond->dev, "option %s: unable to set because the bond device is up\n", - opt->name); + scnprintf(buf, bufsize, "option %s: unable to set because the bond device is up", + opt->name); break; case -ENODEV: if (val && val->string) { p = strchr(val->string, '\n'); if (p) *p = '\0'; - netdev_err(bond->dev, "option %s: interface %s does not exist!\n", - opt->name, val->string); + scnprintf(buf, bufsize, "option %s: interface %s does not exist!", + opt->name, val->string); } break; default: @@ -713,7 +723,8 @@ static void bond_opt_error_interpret(struct bonding *bond, * must be obtained before calling this function. */ int __bond_opt_set(struct bonding *bond, - unsigned int option, struct bond_opt_value *val) + unsigned int option, struct bond_opt_value *val, + struct netlink_ext_ack *extack) { const struct bond_opt_value *retval = NULL; const struct bond_option *opt; @@ -734,8 +745,17 @@ int __bond_opt_set(struct bonding *bond, } ret = opt->set(bond, retval); out: - if (ret) - bond_opt_error_interpret(bond, opt, ret, val); + if (ret) { + static char buf[120]; + buf[0] = '\0'; + bond_opt_error_interpret(bond, opt, ret, val, buf, sizeof(buf)); + if (buf[0] != '\0') { + if (extack) + extack->_msg = buf; + else + netdev_err(bond->dev, "Error: %s\n", buf); + } + } return ret; } @@ -757,7 +777,7 @@ int __bond_opt_set_notify(struct bonding *bond, ASSERT_RTNL(); - ret = __bond_opt_set(bond, option, val); + ret = __bond_opt_set(bond, option, val, NULL); if (!ret && (bond->dev->reg_state == NETREG_REGISTERED)) call_netdevice_notifiers(NETDEV_CHANGEINFODATA, bond->dev); diff --git a/include/net/bond_options.h b/include/net/bond_options.h index 61b49063791c..ae38557adc25 100644 --- a/include/net/bond_options.h +++ b/include/net/bond_options.h @@ -107,7 +107,7 @@ struct bond_option { }; int __bond_opt_set(struct bonding *bond, unsigned int option, - struct bond_opt_value *val); + struct bond_opt_value *val, struct netlink_ext_ack *extack); int __bond_opt_set_notify(struct bonding *bond, unsigned int option, struct bond_opt_value *val); int bond_opt_tryset_rtnl(struct bonding *bond, unsigned int option, char *buf);
Add support for reporting errors via extack in both bond_newlink and bond_changelink. Instead of having to look in the kernel log for why an option was not correct just report the error to the user via the extack variable. What is currently reported today: ip link add bond0 type bond ip link set bond0 up ip link set bond0 type bond mode 4 RTNETLINK answers: Device or resource busy After this change: ip link add bond0 type bond ip link set bond0 up ip link set bond0 type bond mode 4 Error: option mode: unable to set because the bond device is up. Signed-off-by: Jonathan Toppins <jtoppins@redhat.com> --- Notes: This is an RFC because the current NL_SET_ERR_MSG() macros do not support printf like semantics so I rolled my own buffer setting in __bond_opt_set(). The issue is I could not quite figure out the life-cycle of the buffer, if rtnl lock is held until after the text buffer is copied into the packet then we are ok, otherwise, some other type of buffer management scheme will be needed as this could result in corrupted error messages when modifying multiple bonds. drivers/net/bonding/bond_netlink.c | 87 ++++++++++++++++++------------ drivers/net/bonding/bond_options.c | 62 +++++++++++++-------- include/net/bond_options.h | 2 +- 3 files changed, 96 insertions(+), 55 deletions(-)