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| author | David Howells <dhowells@redhat.com> | 2018-11-01 14:39:53 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-11-03 07:59:26 +0100 |
| commit | c7e86acfcee30794dc99a0759924bf7b9d43f1ca (patch) | |
| tree | c31ab320a0a156e97a0442c30e8859071a11d178 /net/rxrpc/ar-internal.h | |
| parent | net: dsa: microchip: initialize mutex before use (diff) | |
| download | linux-c7e86acfcee30794dc99a0759924bf7b9d43f1ca.tar.xz linux-c7e86acfcee30794dc99a0759924bf7b9d43f1ca.zip | |
rxrpc: Fix lockup due to no error backoff after ack transmit error
If the network becomes (partially) unavailable, say by disabling IPv6, the
background ACK transmission routine can get itself into a tizzy by
proposing immediate ACK retransmission. Since we're in the call event
processor, that happens immediately without returning to the workqueue
manager.
The condition should clear after a while when either the network comes back
or the call times out.
Fix this by:
(1) When re-proposing an ACK on failed Tx, don't schedule it immediately.
This will allow a certain amount of time to elapse before we try
again.
(2) Enforce a return to the workqueue manager after a certain number of
iterations of the call processing loop.
(3) Add a backoff delay that increases the delay on deferred ACKs by a
jiffy per failed transmission to a limit of HZ. The backoff delay is
cleared on a successful return from kernel_sendmsg().
(4) Cancel calls immediately if the opening sendmsg fails. The layer
above can arrange retransmission or rotate to another server.
Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rxrpc/ar-internal.h')
| -rw-r--r-- | net/rxrpc/ar-internal.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index 382196e57a26..bc628acf4f4f 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -611,6 +611,7 @@ struct rxrpc_call { * not hard-ACK'd packet follows this. */ rxrpc_seq_t tx_top; /* Highest Tx slot allocated. */ + u16 tx_backoff; /* Delay to insert due to Tx failure */ /* TCP-style slow-start congestion control [RFC5681]. Since the SMSS * is fixed, we keep these numbers in terms of segments (ie. DATA |