[PATCH net] Revert "neighbour: force neigh_invalidate when NUD_FAILED update is from admin"

[PATCH net] Revert "neighbour: force neigh_invalidate when NUD_FAILED update is from admin"

[Roopa Prabhu]

From: Roopa Prabhu <roopa@cumulusnetworks.com>

This reverts commit 8e326289e3069dfc9fa9c209924668dd031ab8ef.

This patch results in unnecessary netlink notification when one
tries to delete a neigh entry already in NUD_FAILED state. Found
this with a buggy app that tries to delete a NUD_FAILED entry
repeatedly. While the notification issue can be fixed with more
checks, adding more complexity here seems unnecessary. Also,
recent tests with other changes in the neighbour code have
shown that the INCOMPLETE and PROBE checks are good enough for
the original issue.

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
---
Dave, Sorry about the revert so late in the release. The issue
is not serious, but i think its better to revert before
it gets into a released kernel. I am happy to fix the
notification issue but seems unnecessary at this point.
Thanks.

 net/core/neighbour.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 91592fc..4e07824 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1148,8 +1148,7 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
 		neigh->nud_state = new;
 		err = 0;
 		notify = old & NUD_VALID;
-		if (((old & (NUD_INCOMPLETE | NUD_PROBE)) ||
-		     (flags & NEIGH_UPDATE_F_ADMIN)) &&
+		if ((old & (NUD_INCOMPLETE | NUD_PROBE)) &&
 		    (new & NUD_FAILED)) {
 			neigh_invalidate(neigh);
 			notify = 1;
-- 
2.1.4

Re: [PATCH net] Revert "neighbour: force neigh_invalidate when NUD_FAILED update is from admin"

[David Miller]

From: Roopa Prabhu <roopa@cumulusnetworks.com>
Date: Sat, 20 Oct 2018 18:09:31 -0700

> From: Roopa Prabhu <roopa@cumulusnetworks.com>
> 
> This reverts commit 8e326289e3069dfc9fa9c209924668dd031ab8ef.
> 
> This patch results in unnecessary netlink notification when one
> tries to delete a neigh entry already in NUD_FAILED state. Found
> this with a buggy app that tries to delete a NUD_FAILED entry
> repeatedly. While the notification issue can be fixed with more
> checks, adding more complexity here seems unnecessary. Also,
> recent tests with other changes in the neighbour code have
> shown that the INCOMPLETE and PROBE checks are good enough for
> the original issue.
> 
> Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>

Applied, thanks.