From e44ef4e4516cce783e95d7221936aa9a4f325ad9 Mon Sep 17 00:00:00 2001 From: Aya Levin Date: Thu, 16 May 2019 09:49:20 +0300 Subject: [PATCH] devlink: Hang reporter's dump method on a dumpit cb The devlink health reporter provides a dump method on an error. Dump may contain a large amount of data, in this case doit cb isn't sufficient. This is because the user side is blocking and doesn't allow draining of the socket until the socket runs out of buffers. Using dumpit cb is the correct way to go. Please note that thankfully the dump op is not yet implemented in any driver and therefore this change is not breaking userspace. Fixes: 35455e23e6f3 ("devlink: Add health dump {get,clear} commands") Signed-off-by: Aya Levin Acked-by: Jiri Pirko Signed-off-by: Saeed Mahameed --- net/core/devlink.c | 118 ++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 98 insertions(+), 20 deletions(-) diff --git a/net/core/devlink.c b/net/core/devlink.c index fd15a66..4baf716 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -4518,6 +4518,35 @@ nla_put_failure: return err; } +static int devlink_fmsg_dumpit(struct devlink_fmsg *fmsg, struct sk_buff *skb, + struct netlink_callback *cb, + enum devlink_command cmd) +{ + int index = cb->args[0]; + int tmp_index = index; + void *hdr; + int err; + + hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq, + &devlink_nl_family, NLM_F_ACK | NLM_F_MULTI, cmd); + if (!hdr) { + err = -EMSGSIZE; + goto nla_put_failure; + } + + err = devlink_fmsg_prepare_skb(fmsg, skb, &index); + if ((err && err != -EMSGSIZE) || tmp_index == index) + goto nla_put_failure; + + cb->args[0] = index; + genlmsg_end(skb, hdr); + return skb->len; + +nla_put_failure: + genlmsg_cancel(skb, hdr); + return err; +} + struct devlink_health_reporter { struct list_head list; void *priv; @@ -4750,17 +4779,16 @@ int devlink_health_report(struct devlink_health_reporter *reporter, EXPORT_SYMBOL_GPL(devlink_health_report); static struct devlink_health_reporter * -devlink_health_reporter_get_from_info(struct devlink *devlink, - struct genl_info *info) +devlink_health_reporter_get_from_attrs(struct devlink *devlink, + struct nlattr **attrs) { struct devlink_health_reporter *reporter; char *reporter_name; - if (!info->attrs[DEVLINK_ATTR_HEALTH_REPORTER_NAME]) + if (!attrs[DEVLINK_ATTR_HEALTH_REPORTER_NAME]) return NULL; - reporter_name = - nla_data(info->attrs[DEVLINK_ATTR_HEALTH_REPORTER_NAME]); + reporter_name = nla_data(attrs[DEVLINK_ATTR_HEALTH_REPORTER_NAME]); mutex_lock(&devlink->reporters_lock); reporter = devlink_health_reporter_find_by_name(devlink, reporter_name); if (reporter) @@ -4769,6 +4797,48 @@ devlink_health_reporter_get_from_info(struct devlink *devlink, return reporter; } +static struct devlink_health_reporter * +devlink_health_reporter_get_from_info(struct devlink *devlink, + struct genl_info *info) +{ + return devlink_health_reporter_get_from_attrs(devlink, info->attrs); +} + +static struct devlink_health_reporter * +devlink_health_reporter_get_from_cb(struct netlink_callback *cb) +{ + struct devlink_health_reporter *reporter; + struct devlink *devlink; + struct nlattr **attrs; + int err; + + attrs = kmalloc_array(DEVLINK_ATTR_MAX + 1, sizeof(*attrs), GFP_KERNEL); + if (!attrs) + return NULL; + + err = nlmsg_parse_deprecated(cb->nlh, + GENL_HDRLEN + devlink_nl_family.hdrsize, + attrs, DEVLINK_ATTR_MAX, + devlink_nl_family.policy, cb->extack); + if (err) + goto free; + + mutex_lock(&devlink_mutex); + devlink = devlink_get_from_attrs(sock_net(cb->skb->sk), attrs); + if (IS_ERR(devlink)) + goto unlock; + + reporter = devlink_health_reporter_get_from_attrs(devlink, attrs); + mutex_unlock(&devlink_mutex); + kfree(attrs); + return reporter; +unlock: + mutex_unlock(&devlink_mutex); +free: + kfree(attrs); + return NULL; +} + static void devlink_health_reporter_put(struct devlink_health_reporter *reporter) { @@ -5004,32 +5074,40 @@ out: return err; } -static int devlink_nl_cmd_health_reporter_dump_get_doit(struct sk_buff *skb, - struct genl_info *info) +static int +devlink_nl_cmd_health_reporter_dump_get_dumpit(struct sk_buff *skb, + struct netlink_callback *cb) { - struct devlink *devlink = info->user_ptr[0]; struct devlink_health_reporter *reporter; + u64 start = cb->args[0]; int err; - reporter = devlink_health_reporter_get_from_info(devlink, info); + reporter = devlink_health_reporter_get_from_cb(cb); if (!reporter) return -EINVAL; if (!reporter->ops->dump) { - devlink_health_reporter_put(reporter); - return -EOPNOTSUPP; + err = -EOPNOTSUPP; + goto out; } - mutex_lock(&reporter->dump_lock); - err = devlink_health_do_dump(reporter, NULL); - if (err) - goto out; - - err = devlink_fmsg_snd(reporter->dump_fmsg, info, - DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET, 0); + if (!start) { + err = devlink_health_do_dump(reporter, NULL); + if (err) + goto unlock; + cb->args[1] = reporter->dump_ts; + } + if (!reporter->dump_fmsg || cb->args[1] != reporter->dump_ts) { + NL_SET_ERR_MSG_MOD(cb->extack, "Dump trampled, please retry"); + err = -EAGAIN; + goto unlock; + } -out: + err = devlink_fmsg_dumpit(reporter->dump_fmsg, skb, cb, + DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET); +unlock: mutex_unlock(&reporter->dump_lock); +out: devlink_health_reporter_put(reporter); return err; } @@ -5366,7 +5444,7 @@ static const struct genl_ops devlink_nl_ops[] = { { .cmd = DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET, .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, - .doit = devlink_nl_cmd_health_reporter_dump_get_doit, + .dumpit = devlink_nl_cmd_health_reporter_dump_get_dumpit, .flags = GENL_ADMIN_PERM, .internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK | DEVLINK_NL_FLAG_NO_LOCK, -- 2.7.4