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[net-next,02/14] nexthop: __nh_notifier_single_info_init(): Make nh_info an argument

Message ID 4e2447a8266746d01da711fa07566099b9cbc75e.1615387786.git.petrm@nvidia.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series nexthop: Resilient next-hop groups | expand

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Commit Message

Petr Machata March 10, 2021, 3:02 p.m. UTC 
The cited function currently uses rtnl_dereference() to get nh_info from a
handed-in nexthop. However, under the resilient hashing scheme, this
function will not always be called under RTNL, sometimes the mutual
exclusion will be achieved differently. Therefore move the nh_info
extraction from the function to its callers to make it possible to use a
different synchronization guarantee.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
---
 net/ipv4/nexthop.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

Comments

David Ahern March 11, 2021, 3:21 p.m. UTC | #1 
On 3/10/21 8:02 AM, Petr Machata wrote:
> The cited function currently uses rtnl_dereference() to get nh_info from a
> handed-in nexthop. However, under the resilient hashing scheme, this
> function will not always be called under RTNL, sometimes the mutual
> exclusion will be achieved differently. Therefore move the nh_info
> extraction from the function to its callers to make it possible to use a
> different synchronization guarantee.
> 
> Signed-off-by: Petr Machata <petrm@nvidia.com>
> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
> ---
>  net/ipv4/nexthop.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 

Reviewed-by: David Ahern <dsahern@kernel.org>
diff mbox series

Patch

diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index f723dc97dcd3..69c8b50a936e 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -52,10 +52,8 @@  static bool nexthop_notifiers_is_empty(struct net *net)
 
 static void
 __nh_notifier_single_info_init(struct nh_notifier_single_info *nh_info,
-			       const struct nexthop *nh)
+			       const struct nh_info *nhi)
 {
-	struct nh_info *nhi = rtnl_dereference(nh->nh_info);
-
 	nh_info->dev = nhi->fib_nhc.nhc_dev;
 	nh_info->gw_family = nhi->fib_nhc.nhc_gw_family;
 	if (nh_info->gw_family == AF_INET)
@@ -71,12 +69,14 @@  __nh_notifier_single_info_init(struct nh_notifier_single_info *nh_info,
 static int nh_notifier_single_info_init(struct nh_notifier_info *info,
 					const struct nexthop *nh)
 {
+	struct nh_info *nhi = rtnl_dereference(nh->nh_info);
+
 	info->type = NH_NOTIFIER_INFO_TYPE_SINGLE;
 	info->nh = kzalloc(sizeof(*info->nh), GFP_KERNEL);
 	if (!info->nh)
 		return -ENOMEM;
 
-	__nh_notifier_single_info_init(info->nh, nh);
+	__nh_notifier_single_info_init(info->nh, nhi);
 
 	return 0;
 }
@@ -103,11 +103,13 @@  static int nh_notifier_mp_info_init(struct nh_notifier_info *info,
 
 	for (i = 0; i < num_nh; i++) {
 		struct nh_grp_entry *nhge = &nhg->nh_entries[i];
+		struct nh_info *nhi;
 
+		nhi = rtnl_dereference(nhge->nh->nh_info);
 		info->nh_grp->nh_entries[i].id = nhge->nh->id;
 		info->nh_grp->nh_entries[i].weight = nhge->weight;
 		__nh_notifier_single_info_init(&info->nh_grp->nh_entries[i].nh,
-					       nhge->nh);
+					       nhi);
 	}
 
 	return 0;