From 5d4f78564c9ca38146102c4f8998edcad5afbc22 Mon Sep 17 00:00:00 2001 From: Julian Wiedmann Date: Wed, 11 Mar 2020 18:07:11 +0100 Subject: s390/qeth: implement smarter resizing of the RX buffer pool The RX buffer pool is allocated in qeth_alloc_qdio_queues(). A subsequent pool resizing is then handled in a very simple way: first free the current pool, then allocate a new pool of the requested size. There's two ways where this can go wrong: 1. if the resize action happens _before_ the initial pool was allocated, then a subsequent initialization will call qeth_alloc_qdio_queues() and fill the pool with a second(!) set of pages. We consume twice the planned amount of memory. This is easy to fix - just skip the resizing if the queues haven't been allocated yet. 2. if the initial pool was created by qeth_alloc_qdio_queues() but a subsequent resizing fails, then the device has no(!) RX buffer pool. The next initialization will _not_ call qeth_alloc_qdio_queues(), and attempting to back the RX buffers with pages in qeth_init_qdio_queues() will fail. Not very difficult to fix either - instead of re-allocating the whole pool, just allocate/free as many entries to match the desired size. Fixes: 4a71df50047f ("qeth: new qeth device driver") Signed-off-by: Julian Wiedmann Signed-off-by: David S. Miller --- drivers/s390/net/qeth_l3_sys.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'drivers/s390/net/qeth_l3_sys.c') diff --git a/drivers/s390/net/qeth_l3_sys.c b/drivers/s390/net/qeth_l3_sys.c index 29f2517d2a31..a3d1c3bdfadb 100644 --- a/drivers/s390/net/qeth_l3_sys.c +++ b/drivers/s390/net/qeth_l3_sys.c @@ -206,12 +206,11 @@ static ssize_t qeth_l3_dev_sniffer_store(struct device *dev, qdio_get_ssqd_desc(CARD_DDEV(card), &card->ssqd); if (card->ssqd.qdioac2 & CHSC_AC2_SNIFFER_AVAILABLE) { card->options.sniffer = i; - if (card->qdio.init_pool.buf_count != - QETH_IN_BUF_COUNT_MAX) - qeth_realloc_buffer_pool(card, - QETH_IN_BUF_COUNT_MAX); - } else + qeth_resize_buffer_pool(card, QETH_IN_BUF_COUNT_MAX); + } else { rc = -EPERM; + } + break; default: rc = -EINVAL; -- cgit v1.2.3