genetlink: allow families to use split ops directly

Let families to hook in the new split ops.

They are more flexible and should not be much larger than
full ops. Each split op is 40B while full op is 48B.
Devlink for example has 54 dos and 19 dumps, 2 of the dumps
do not have a do -> 56 full commands = 2688B.
Split ops would have taken 2920B, so 9% more space while
allowing individual per/post doit and per-type policies.

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>

1 files changed, 144 insertions, 26 deletions

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 0a4f1470f442..90b0feb5eb73 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -101,6 +101,17 @@ genl_op_fill_in_reject_policy(const struct genl_family *family,
 	op->maxattr = 1;
 }
 
+static void
+genl_op_fill_in_reject_policy_split(const struct genl_family *family,
+				    struct genl_split_ops *op)
+{
+	if (op->policy)
+		return;
+
+	op->policy = genl_policy_reject_all;
+	op->maxattr = 1;
+}
+
 static const struct genl_family *genl_family_find_byid(unsigned int id)
 {
 	return idr_find(&genl_fam_idr, id);
@@ -118,6 +129,16 @@ static const struct genl_family *genl_family_find_byname(char *name)
 	return NULL;
 }
 
+struct genl_op_iter {
+	const struct genl_family *family;
+	struct genl_split_ops doit;
+	struct genl_split_ops dumpit;
+	int cmd_idx;
+	int entry_idx;
+	u32 cmd;
+	u8 flags;
+};
+
 static void genl_op_from_full(const struct genl_family *family,
 			      unsigned int i, struct genl_ops *op)
 {
@@ -176,6 +197,50 @@ static int genl_get_cmd_small(u32 cmd, const struct genl_family *family,
 	return -ENOENT;
 }
 
+static void genl_op_from_split(struct genl_op_iter *iter)
+{
+	const struct genl_family *family = iter->family;
+	int i, cnt = 0;
+
+	i = iter->entry_idx - family->n_ops - family->n_small_ops;
+
+	if (family->split_ops[i + cnt].flags & GENL_CMD_CAP_DO) {
+		iter->doit = family->split_ops[i + cnt];
+		genl_op_fill_in_reject_policy_split(family, &iter->doit);
+		cnt++;
+	} else {
+		memset(&iter->doit, 0, sizeof(iter->doit));
+	}
+
+	if (i + cnt < family->n_split_ops &&
+	    family->split_ops[i + cnt].flags & GENL_CMD_CAP_DUMP) {
+		iter->dumpit = family->split_ops[i + cnt];
+		genl_op_fill_in_reject_policy_split(family, &iter->dumpit);
+		cnt++;
+	} else {
+		memset(&iter->dumpit, 0, sizeof(iter->dumpit));
+	}
+
+	WARN_ON(!cnt);
+	iter->entry_idx += cnt;
+}
+
+static int
+genl_get_cmd_split(u32 cmd, u8 flag, const struct genl_family *family,
+		   struct genl_split_ops *op)
+{
+	int i;
+
+	for (i = 0; i < family->n_split_ops; i++)
+		if (family->split_ops[i].cmd == cmd &&
+		    family->split_ops[i].flags & flag) {
+			*op = family->split_ops[i];
+			return 0;
+		}
+
+	return -ENOENT;
+}
+
 static int
 genl_cmd_full_to_split(struct genl_split_ops *op,
 		       const struct genl_family *family,
@@ -227,50 +292,60 @@ genl_get_cmd(u32 cmd, u8 flags, const struct genl_family *family,
 	err = genl_get_cmd_full(cmd, family, &full);
 	if (err == -ENOENT)
 		err = genl_get_cmd_small(cmd, family, &full);
-	if (err) {
-		memset(op, 0, sizeof(*op));
-		return err;
-	}
+	/* Found one of legacy forms */
+	if (err == 0)
+		return genl_cmd_full_to_split(op, family, &full, flags);
 
-	return genl_cmd_full_to_split(op, family, &full, flags);
+	err = genl_get_cmd_split(cmd, flags, family, op);
+	if (err)
+		memset(op, 0, sizeof(*op));
+	return err;
 }
 
-struct genl_op_iter {
-	const struct genl_family *family;
-	struct genl_split_ops doit;
-	struct genl_split_ops dumpit;
-	int i;
-	u32 cmd;
-	u8 flags;
-};
-
 static bool
 genl_op_iter_init(const struct genl_family *family, struct genl_op_iter *iter)
 {
 	iter->family = family;
-	iter->i = 0;
+	iter->cmd_idx = 0;
+	iter->entry_idx = 0;
 
 	iter->flags = 0;
 
-	return iter->family->n_ops + iter->family->n_small_ops;
+	return iter->family->n_ops +
+		iter->family->n_small_ops +
+		iter->family->n_split_ops;
 }
 
 static bool genl_op_iter_next(struct genl_op_iter *iter)
 {
 	const struct genl_family *family = iter->family;
+	bool legacy_op = true;
 	struct genl_ops op;
 
-	if (iter->i < family->n_ops)
-		genl_op_from_full(family, iter->i, &op);
-	else if (iter->i < family->n_ops + family->n_small_ops)
-		genl_op_from_small(family, iter->i - family->n_ops, &op);
-	else
+	if (iter->entry_idx < family->n_ops) {
+		genl_op_from_full(family, iter->entry_idx, &op);
+	} else if (iter->entry_idx < family->n_ops + family->n_small_ops) {
+		genl_op_from_small(family, iter->entry_idx - family->n_ops,
+				   &op);
+	} else if (iter->entry_idx <
+		   family->n_ops + family->n_small_ops + family->n_split_ops) {
+		legacy_op = false;
+		/* updates entry_idx */
+		genl_op_from_split(iter);
+	} else {
 		return false;
+	}
 
-	iter->i++;
+	iter->cmd_idx++;
 
-	genl_cmd_full_to_split(&iter->doit, family, &op, GENL_CMD_CAP_DO);
-	genl_cmd_full_to_split(&iter->dumpit, family, &op, GENL_CMD_CAP_DUMP);
+	if (legacy_op) {
+		iter->entry_idx++;
+
+		genl_cmd_full_to_split(&iter->doit, family,
+				       &op, GENL_CMD_CAP_DO);
+		genl_cmd_full_to_split(&iter->dumpit, family,
+				       &op, GENL_CMD_CAP_DUMP);
+	}
 
 	iter->cmd = iter->doit.cmd | iter->dumpit.cmd;
 	iter->flags = iter->doit.flags | iter->dumpit.flags;
@@ -286,7 +361,7 @@ genl_op_iter_copy(struct genl_op_iter *dst, struct genl_op_iter *src)
 
 static unsigned int genl_op_iter_idx(struct genl_op_iter *iter)
 {
-	return iter->i;
+	return iter->cmd_idx;
 }
 
 static int genl_allocate_reserve_groups(int n_groups, int *first_id)
@@ -454,12 +529,22 @@ static void genl_unregister_mc_groups(const struct genl_family *family)
 	}
 }
 
+static bool genl_split_op_check(const struct genl_split_ops *op)
+{
+	if (WARN_ON(hweight8(op->flags & (GENL_CMD_CAP_DO |
+					  GENL_CMD_CAP_DUMP)) != 1))
+		return true;
+	return false;
+}
+
 static int genl_validate_ops(const struct genl_family *family)
 {
 	struct genl_op_iter i, j;
+	unsigned int s;
 
 	if (WARN_ON(family->n_ops && !family->ops) ||
-	    WARN_ON(family->n_small_ops && !family->small_ops))
+	    WARN_ON(family->n_small_ops && !family->small_ops) ||
+	    WARN_ON(family->n_split_ops && !family->split_ops))
 		return -EINVAL;
 
 	for (genl_op_iter_init(family, &i); genl_op_iter_next(&i); ) {
@@ -477,6 +562,39 @@ static int genl_validate_ops(const struct genl_family *family)
 		}
 	}
 
+	if (family->n_split_ops) {
+		if (genl_split_op_check(&family->split_ops[0]))
+			return -EINVAL;
+	}
+
+	for (s = 1; s < family->n_split_ops; s++) {
+		const struct genl_split_ops *a, *b;
+
+		a = &family->split_ops[s - 1];
+		b = &family->split_ops[s];
+
+		if (genl_split_op_check(b))
+			return -EINVAL;
+
+		/* Check sort order */
+		if (a->cmd < b->cmd)
+			continue;
+
+		if (a->internal_flags != b->internal_flags ||
+		    ((a->flags ^ b->flags) & ~(GENL_CMD_CAP_DO |
+					       GENL_CMD_CAP_DUMP))) {
+			WARN_ON(1);
+			return -EINVAL;
+		}
+
+		if ((a->flags & GENL_CMD_CAP_DO) &&
+		    (b->flags & GENL_CMD_CAP_DUMP))
+			continue;
+
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
 	return 0;
 }