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From:   David Howells <dhowells@redhat.com>
To:     torvalds@linux-foundation.org
cc:     dhowells@redhat.com, Marc Dionne <marc.dionne@auristor.com>,
        linux-afs@lists.infradead.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] afs: Fix vlserver probe RTT handling
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Content-ID: <697563.1686951579.1@warthog.procyon.org.uk>
Date:   Fri, 16 Jun 2023 22:39:39 +0100
Message-ID: <697564.1686951579@warthog.procyon.org.uk>
Precedence: bulk

Hi Linus,

Could you apply this, please?

Thanks,
David
---

In the same spirit as commit ca57f02295f1 ("afs: Fix fileserver
probe RTT handling"), don't rule out using a vlserver just because
there haven't been enough packets yet to calculate a real rtt.
Always set the server's probe rtt from the estimate provided by
rxrpc_kernel_get_srtt, which is capped at 1 second.

This could lead to EDESTADDRREQ errors when accessing a cell for
the first time, even though the vl servers are known and have
responded to a probe.

Fixes: 1d4adfaf6574 ("rxrpc: Make rxrpc_kernel_get_srtt() indicate validity")
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-afs@lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2023-June/006746.html
---
 fs/afs/vl_probe.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/afs/vl_probe.c b/fs/afs/vl_probe.c
index d1c7068b4346..58452b86e672 100644
--- a/fs/afs/vl_probe.c
+++ b/fs/afs/vl_probe.c
@@ -115,8 +115,8 @@ void afs_vlserver_probe_result(struct afs_call *call)
 		}
 	}
 
-	if (rxrpc_kernel_get_srtt(call->net->socket, call->rxcall, &rtt_us) &&
-	    rtt_us < server->probe.rtt) {
+	rxrpc_kernel_get_srtt(call->net->socket, call->rxcall, &rtt_us);
+	if (rtt_us < server->probe.rtt) {
 		server->probe.rtt = rtt_us;
 		server->rtt = rtt_us;
 		alist->preferred = index;