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authorUrsula Braun <ubraun@linux.ibm.com>2019-02-04 13:44:45 +0100
committerDavid S. Miller <davem@davemloft.net>2019-02-04 09:11:19 -0800
commitb8649efad879c69c7ab1f19ce8814fcabef1f72b (patch)
treec5f16db7dbde8bb5da8db0b74f538a2a58c78036 /net/smc/smc_tx.c
parentad6f317f720f4a3121756c23831a43dda9b095e5 (diff)
net/smc: fix sender_free computation
In some scenarios a separate consumer cursor update is necessary. The decision is made in smc_tx_consumer_cursor_update(). The sender_free computation could be wrong: The rx confirmed cursor is always smaller than or equal to the rx producer cursor. The parameters in the smc_curs_diff() call have to be exchanged, otherwise sender_free might even be negative. And if more data arrives local_rx_ctrl.prod might be updated, enabling a cursor difference between local_rx_ctrl.prod and rx confirmed cursor larger than the RMB size. This case is not covered by smc_curs_diff(). Thus function smc_curs_diff_large() is introduced here. If a recvmsg() is processed in parallel, local_tx_ctrl.cons might change during smc_cdc_msg_send. Make sure rx_curs_confirmed is updated with the actually sent local_tx_ctrl.cons value. Fixes: e82f2e31f559 ("net/smc: optimize consumer cursor updates") Signed-off-by: Ursula Braun <ubraun@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/smc/smc_tx.c')
-rw-r--r--net/smc/smc_tx.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index 2fdfaff60cf9..f93f3580c100 100644
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -595,7 +595,8 @@ void smc_tx_consumer_update(struct smc_connection *conn, bool force)
if (to_confirm > conn->rmbe_update_limit) {
smc_curs_copy(&prod, &conn->local_rx_ctrl.prod, conn);
sender_free = conn->rmb_desc->len -
- smc_curs_diff(conn->rmb_desc->len, &prod, &cfed);
+ smc_curs_diff_large(conn->rmb_desc->len,
+ &cfed, &prod);
}
if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||