genetlink: use iterator in the op to policy map dumping

We can't put the full iterator in the struct ctrl_dump_policy_ctx
because dump context is statically sized by netlink core.
Allocate it dynamically.

Rename policy to dump_map to make the logic a little easier to follow.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 06bf091..4b8c65d 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -1252,10 +1252,10 @@ static int genl_ctrl_event(int event, const struct genl_family *family,
 struct ctrl_dump_policy_ctx {
        struct netlink_policy_dump_state *state;
        const struct genl_family *rt;
-       unsigned int opidx;
+       struct genl_op_iter *op_iter;
        u32 op;
        u16 fam_id;
-       u8 policies:1,
+       u8 dump_map:1,
           single_op:1;
 };
 
@@ -1325,9 +1325,16 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb)
 
                if (!ctx->state)
                        return -ENODATA;
+
+               ctx->dump_map = 1;
                return 0;
        }
 
+       ctx->op_iter = kmalloc(sizeof(*ctx->op_iter), GFP_KERNEL);
+       if (!ctx->op_iter)
+               return -ENOMEM;
+       ctx->dump_map = genl_op_iter_init(rt, ctx->op_iter);
+
        for (genl_op_iter_init(rt, &i); genl_op_iter_next(&i); ) {
                if (i.doit.policy) {
                        err = netlink_policy_dump_add_policy(&ctx->state,
@@ -1345,12 +1352,16 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb)
                }
        }
 
-       if (!ctx->state)
-               return -ENODATA;
+       if (!ctx->state) {
+               err = -ENODATA;
+               goto err_free_op_iter;
+       }
        return 0;
 
 err_free_state:
        netlink_policy_dump_free(ctx->state);
+err_free_op_iter:
+       kfree(ctx->op_iter);
        return err;
 }
 
@@ -1430,11 +1441,10 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
        struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
        void *hdr;
 
-       if (!ctx->policies) {
-               struct genl_split_ops doit, dumpit;
-               struct genl_ops op;
-
+       if (ctx->dump_map) {
                if (ctx->single_op) {
+                       struct genl_split_ops doit, dumpit;
+
                        if (genl_get_cmd(ctx->op, GENL_CMD_CAP_DO,
                                         ctx->rt, &doit) &&
                            genl_get_cmd(ctx->op, GENL_CMD_CAP_DUMP,
@@ -1446,26 +1456,18 @@ static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb)
                        if (ctrl_dumppolicy_put_op(skb, cb, &doit, &dumpit))
                                return skb->len;
 
-                       /* don't enter the loop below */
-                       ctx->opidx = genl_get_cmd_cnt(ctx->rt);
+                       /* done with the per-op policy index list */
+                       ctx->dump_map = 0;
                }
 
-               while (ctx->opidx < genl_get_cmd_cnt(ctx->rt)) {
-                       genl_get_cmd_by_index(ctx->opidx, ctx->rt, &op);
-
-                       genl_cmd_full_to_split(&doit, ctx->rt,
-                                              &op, GENL_CMD_CAP_DO);
-                       genl_cmd_full_to_split(&dumpit, ctx->rt,
-                                              &op, GENL_CMD_CAP_DUMP);
-
-                       if (ctrl_dumppolicy_put_op(skb, cb, &doit, &dumpit))
+               while (ctx->dump_map) {
+                       if (ctrl_dumppolicy_put_op(skb, cb,
+                                                  &ctx->op_iter->doit,
+                                                  &ctx->op_iter->dumpit))
                                return skb->len;
 
-                       ctx->opidx++;
+                       ctx->dump_map = genl_op_iter_next(ctx->op_iter);
                }
-
-               /* completed with the per-op policy index list */
-               ctx->policies = true;
        }
 
        while (netlink_policy_dump_loop(ctx->state)) {
@@ -1498,6 +1500,7 @@ static int ctrl_dumppolicy_done(struct netlink_callback *cb)
 {
        struct ctrl_dump_policy_ctx *ctx = (void *)cb->ctx;
 
+       kfree(ctx->op_iter);
        netlink_policy_dump_free(ctx->state);
        return 0;
 }