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| author |   Julian Wiedmann <jwi@linux.ibm.com> | 2018-07-19 12:43:48 +0200 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2018-07-21 10:12:29 -0700 |
| commit | a702349a4099cd5a7bab0904689d8e0bf8dcd622 (patch) | |
| tree | 9c4fecc85ff313af8459d3181fedf830d9962114 /drivers/s390 | |
| parent | Merge branch 'hns3-misc-cleanups' (diff) | |
| download | linux-dev-a702349a4099cd5a7bab0904689d8e0bf8dcd622.tar.xz linux-dev-a702349a4099cd5a7bab0904689d8e0bf8dcd622.zip | |
s390/qeth: fix race in used-buffer accounting
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>
Diffstat (limited to 'drivers/s390')
| -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 d80972b9bfc7..f7ddd6455638 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -3506,13 +3506,14 @@ 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 */ |