From adc848450ff84e961cf7966b8a475889a92a9fd3 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Fri, 2 Oct 2020 14:49:55 -0700 Subject: genetlink: add a structure for dump state Whenever netlink dump uses more than 2 cb->args[] entries code gets hard to read. We're about to add more state to ctrl_dumppolicy() so create a structure. Since the structure is typed and clearly named we can remove the local fam_id variable and use ctx->fam_id directly. v3: - rebase onto explicit free fix v1: - s/nl_policy_dump/netlink_policy_dump_state/ - forward declare struct netlink_policy_dump_state, and move from passing unsigned long to actual pointer type - add build bug on - u16 fam_id - s/args/ctx/ Signed-off-by: Jakub Kicinski Reviewed-by: Johannes Berg Signed-off-by: David S. Miller --- include/net/netlink.h | 11 +++++++---- net/netlink/genetlink.c | 28 ++++++++++++++++++---------- net/netlink/policy.c | 31 ++++++++++++++----------------- 3 files changed, 39 insertions(+), 31 deletions(-) diff --git a/include/net/netlink.h b/include/net/netlink.h index 9e7eca961a98..00258590f2cb 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -1935,11 +1935,14 @@ void nla_get_range_unsigned(const struct nla_policy *pt, void nla_get_range_signed(const struct nla_policy *pt, struct netlink_range_validation_signed *range); +struct netlink_policy_dump_state; + int netlink_policy_dump_start(const struct nla_policy *policy, unsigned int maxtype, - unsigned long *state); -bool netlink_policy_dump_loop(unsigned long state); -int netlink_policy_dump_write(struct sk_buff *skb, unsigned long state); -void netlink_policy_dump_free(unsigned long state); + struct netlink_policy_dump_state **state); +bool netlink_policy_dump_loop(struct netlink_policy_dump_state *state); +int netlink_policy_dump_write(struct sk_buff *skb, + struct netlink_policy_dump_state *state); +void netlink_policy_dump_free(struct netlink_policy_dump_state *state); #endif diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 42a3c6c7a5ee..1febc7db1110 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -1102,13 +1102,20 @@ static int genl_ctrl_event(int event, const struct genl_family *family, return 0; } +struct ctrl_dump_policy_ctx { + struct netlink_policy_dump_state *state; + u16 fam_id; +}; + static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) { + struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx; const struct genl_family *rt; - unsigned int fam_id = cb->args[0]; int err; - if (!fam_id) { + BUILD_BUG_ON(sizeof(*ctx) > sizeof(cb->ctx)); + + if (!ctx->fam_id) { struct nlattr *tb[CTRL_ATTR_MAX + 1]; err = genlmsg_parse(cb->nlh, &genl_ctrl, tb, @@ -1121,28 +1128,28 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) return -EINVAL; if (tb[CTRL_ATTR_FAMILY_ID]) { - fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]); + ctx->fam_id = nla_get_u16(tb[CTRL_ATTR_FAMILY_ID]); } else { rt = genl_family_find_byname( nla_data(tb[CTRL_ATTR_FAMILY_NAME])); if (!rt) return -ENOENT; - fam_id = rt->id; + ctx->fam_id = rt->id; } } - rt = genl_family_find_byid(fam_id); + rt = genl_family_find_byid(ctx->fam_id); if (!rt) return -ENOENT; if (!rt->policy) return -ENODATA; - err = netlink_policy_dump_start(rt->policy, rt->maxattr, &cb->args[1]); + err = netlink_policy_dump_start(rt->policy, rt->maxattr, &ctx->state); if (err) return err; - while (netlink_policy_dump_loop(cb->args[1])) { + while (netlink_policy_dump_loop(ctx->state)) { void *hdr; struct nlattr *nest; @@ -1159,7 +1166,7 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) if (!nest) goto nla_put_failure; - if (netlink_policy_dump_write(skb, cb->args[1])) + if (netlink_policy_dump_write(skb, ctx->state)) goto nla_put_failure; nla_nest_end(skb, nest); @@ -1172,13 +1179,14 @@ nla_put_failure: break; } - cb->args[0] = fam_id; return skb->len; } static int ctrl_dumppolicy_done(struct netlink_callback *cb) { - netlink_policy_dump_free(cb->args[1]); + struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx; + + netlink_policy_dump_free(ctx->state); return 0; } diff --git a/net/netlink/policy.c b/net/netlink/policy.c index 7a9792442578..ebc64b20b6ee 100644 --- a/net/netlink/policy.c +++ b/net/netlink/policy.c @@ -14,7 +14,7 @@ #define INITIAL_POLICIES_ALLOC 10 -struct nl_policy_dump { +struct netlink_policy_dump_state { unsigned int policy_idx; unsigned int attr_idx; unsigned int n_alloc; @@ -24,11 +24,11 @@ struct nl_policy_dump { } policies[]; }; -static int add_policy(struct nl_policy_dump **statep, +static int add_policy(struct netlink_policy_dump_state **statep, const struct nla_policy *policy, unsigned int maxtype) { - struct nl_policy_dump *state = *statep; + struct netlink_policy_dump_state *state = *statep; unsigned int n_alloc, i; if (!policy || !maxtype) @@ -62,7 +62,7 @@ static int add_policy(struct nl_policy_dump **statep, return 0; } -static unsigned int get_policy_idx(struct nl_policy_dump *state, +static unsigned int get_policy_idx(struct netlink_policy_dump_state *state, const struct nla_policy *policy) { unsigned int i; @@ -78,13 +78,13 @@ static unsigned int get_policy_idx(struct nl_policy_dump *state, int netlink_policy_dump_start(const struct nla_policy *policy, unsigned int maxtype, - unsigned long *_state) + struct netlink_policy_dump_state **statep) { - struct nl_policy_dump *state; + struct netlink_policy_dump_state *state; unsigned int policy_idx; int err; - if (*_state) + if (*statep) return 0; /* @@ -128,27 +128,26 @@ int netlink_policy_dump_start(const struct nla_policy *policy, } } - *_state = (unsigned long)state; + *statep = state; return 0; } -static bool netlink_policy_dump_finished(struct nl_policy_dump *state) +static bool +netlink_policy_dump_finished(struct netlink_policy_dump_state *state) { return state->policy_idx >= state->n_alloc || !state->policies[state->policy_idx].policy; } -bool netlink_policy_dump_loop(unsigned long _state) +bool netlink_policy_dump_loop(struct netlink_policy_dump_state *state) { - struct nl_policy_dump *state = (void *)_state; - return !netlink_policy_dump_finished(state); } -int netlink_policy_dump_write(struct sk_buff *skb, unsigned long _state) +int netlink_policy_dump_write(struct sk_buff *skb, + struct netlink_policy_dump_state *state) { - struct nl_policy_dump *state = (void *)_state; const struct nla_policy *pt; struct nlattr *policy, *attr; enum netlink_attribute_type type; @@ -306,9 +305,7 @@ nla_put_failure: return -ENOBUFS; } -void netlink_policy_dump_free(unsigned long _state) +void netlink_policy_dump_free(struct netlink_policy_dump_state *state) { - struct nl_policy_dump *state = (void *)_state; - kfree(state); } -- cgit v1.2.3