genetlink: push conditional locking into dumpit/done

Add helpers which take/release the genl mutex based
on family->parallel_ops. Remove the separation between
handling of ops in locked and parallel families.

Future patches would make the duplicated code grow even more.

Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20230814214723.2924989-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 6bd2ce5..0d42856 100644 (file)
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -52,6 +52,18 @@ static void genl_unlock_all(void)
        up_write(&cb_lock);
 }
 
+static void genl_op_lock(const struct genl_family *family)
+{
+       if (!family->parallel_ops)
+               genl_lock();
+}
+
+static void genl_op_unlock(const struct genl_family *family)
+{
+       if (!family->parallel_ops)
+               genl_unlock();
+}
+
 static DEFINE_IDR(genl_fam_idr);
 
 /*
@@ -838,11 +850,9 @@ static int genl_start(struct netlink_callback *cb)
 
        cb->data = info;
        if (ops->start) {
-               if (!ctx->family->parallel_ops)
-                       genl_lock();
+               genl_op_lock(ctx->family);
                rc = ops->start(cb);
-               if (!ctx->family->parallel_ops)
-                       genl_unlock();
+               genl_op_unlock(ctx->family);
        }
 
        if (rc) {
@@ -853,46 +863,34 @@ static int genl_start(struct netlink_callback *cb)
        return rc;
 }
 
-static int genl_lock_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
+static int genl_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 {
-       const struct genl_split_ops *ops = &genl_dumpit_info(cb)->op;
+       const struct genl_dumpit_info *info = genl_dumpit_info(cb);
+       const struct genl_split_ops *ops = &info->op;
        int rc;
 
-       genl_lock();
+       genl_op_lock(info->family);
        rc = ops->dumpit(skb, cb);
-       genl_unlock();
+       genl_op_unlock(info->family);
        return rc;
 }
 
-static int genl_lock_done(struct netlink_callback *cb)
+static int genl_done(struct netlink_callback *cb)
 {
        const struct genl_dumpit_info *info = genl_dumpit_info(cb);
        const struct genl_split_ops *ops = &info->op;
        int rc = 0;
 
        if (ops->done) {
-               genl_lock();
+               genl_op_lock(info->family);
                rc = ops->done(cb);
-               genl_unlock();
+               genl_op_unlock(info->family);
        }
        genl_family_rcv_msg_attrs_free(info->attrs);
        genl_dumpit_info_free(info);
        return rc;
 }
 
-static int genl_parallel_done(struct netlink_callback *cb)
-{
-       const struct genl_dumpit_info *info = genl_dumpit_info(cb);
-       const struct genl_split_ops *ops = &info->op;
-       int rc = 0;
-
-       if (ops->done)
-               rc = ops->done(cb);
-       genl_family_rcv_msg_attrs_free(info->attrs);
-       genl_dumpit_info_free(info);
-       return rc;
-}
-
 static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
                                      struct sk_buff *skb,
                                      struct nlmsghdr *nlh,
@@ -901,6 +899,14 @@ static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
                                      int hdrlen, struct net *net)
 {
        struct genl_start_context ctx;
+       struct netlink_dump_control c = {
+               .module = family->module,
+               .data = &ctx,
+               .start = genl_start,
+               .dump = genl_dumpit,
+               .done = genl_done,
+               .extack = extack,
+       };
        int err;
 
        ctx.family = family;
@@ -909,31 +915,9 @@ static int genl_family_rcv_msg_dumpit(const struct genl_family *family,
        ctx.ops = ops;
        ctx.hdrlen = hdrlen;
 
-       if (!family->parallel_ops) {
-               struct netlink_dump_control c = {
-                       .module = family->module,
-                       .data = &ctx,
-                       .start = genl_start,
-                       .dump = genl_lock_dumpit,
-                       .done = genl_lock_done,
-                       .extack = extack,
-               };
-
-               genl_unlock();
-               err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
-               genl_lock();
-       } else {
-               struct netlink_dump_control c = {
-                       .module = family->module,
-                       .data = &ctx,
-                       .start = genl_start,
-                       .dump = ops->dumpit,
-                       .done = genl_parallel_done,
-                       .extack = extack,
-               };
-
-               err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
-       }
+       genl_op_unlock(family);
+       err = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
+       genl_op_lock(family);
 
        return err;
 }
@@ -1065,13 +1049,9 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
        if (family == NULL)
                return -ENOENT;
 
-       if (!family->parallel_ops)
-               genl_lock();
-
+       genl_op_lock(family);
        err = genl_family_rcv_msg(family, skb, nlh, extack);
-
-       if (!family->parallel_ops)
-               genl_unlock();
+       genl_op_unlock(family);
 
        return err;
 }