diff options
author | Julian Wiedmann <jwi@linux.ibm.com> | 2018-07-19 12:43:48 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-26 08:35:06 +0200 |
commit | 29162495129d39080d21069364f3eb9919509a9a (patch) | |
tree | 0931b8ccd56ecb9e5fda8af0134ef5603b238a42 /drivers | |
parent | 4f3381ab8af23acc958828795477c7f8929e8925 (diff) |
s390/qeth: fix race in used-buffer accounting
[ Upstream commit a702349a4099cd5a7bab0904689d8e0bf8dcd622 ]
By updating q->used_buffers only _after_ do_QDIO() has completed, there
is a potential race against the buffer's TX completion. In the unlikely
case that the TX completion path wins, qeth_qdio_output_handler() would
decrement the counter before qeth_flush_buffers() even incremented it.
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/s390/net/qeth_core_main.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index 95c631125a20..09ac56317f1b 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -3505,13 +3505,14 @@ static void qeth_flush_buffers(struct qeth_qdio_out_q *queue, int index, qdio_flags = QDIO_FLAG_SYNC_OUTPUT; if (atomic_read(&queue->set_pci_flags_count)) qdio_flags |= QDIO_FLAG_PCI_OUT; + atomic_add(count, &queue->used_buffers); + rc = do_QDIO(CARD_DDEV(queue->card), qdio_flags, queue->queue_no, index, count); if (queue->card->options.performance_stats) queue->card->perf_stats.outbound_do_qdio_time += qeth_get_micros() - queue->card->perf_stats.outbound_do_qdio_start_time; - atomic_add(count, &queue->used_buffers); if (rc) { queue->card->stats.tx_errors += count; /* ignore temporary SIGA errors without busy condition */ |