From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: [PATCHv1 net] tg3: fix deadlock in tg3_change_mtu() Date: Tue, 4 Feb 2014 19:01:27 +0000 Message-ID: <1391540487-31207-1-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Nithin Nayak Sujir , Michael Chan , David Vrabel To: Return-path: Received: from smtp02.citrix.com ([66.165.176.63]:42664 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754657AbaBDTBu (ORCPT ); Tue, 4 Feb 2014 14:01:50 -0500 Sender: netdev-owner@vger.kernel.org List-ID: 5780 cards cannot have jumbo frames and TSO enabled together. When jumbo frames are enabled by setting the MTU, the TSO feature must be cleared. This is done indirectly by calling netdev_update_features() which will call tg3_fix_features() to actually clear the flags. netdev_update_features() will also trigger a new netlink message for the feature change event which will result in a call to tg3_get_stats64() which deadlocks on the tg3 lock. Fix this by dropping the tg3 lock while calling netdev_update_features(). This is safe as the device is down and the hardware is stopped. Signed-off-by: David Vrabel --- drivers/net/ethernet/broadcom/tg3.c | 18 +++++++++++------- 1 files changed, 11 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c index e2ca03e..0b344c0 100644 --- a/drivers/net/ethernet/broadcom/tg3.c +++ b/drivers/net/ethernet/broadcom/tg3.c @@ -14077,17 +14077,13 @@ static inline void tg3_set_mtu(struct net_device *dev, struct tg3 *tp, dev->mtu = new_mtu; if (new_mtu > ETH_DATA_LEN) { - if (tg3_flag(tp, 5780_CLASS)) { - netdev_update_features(dev); + if (tg3_flag(tp, 5780_CLASS)) tg3_flag_clear(tp, TSO_CAPABLE); - } else { + else tg3_flag_set(tp, JUMBO_RING_ENABLE); - } } else { - if (tg3_flag(tp, 5780_CLASS)) { + if (tg3_flag(tp, 5780_CLASS)) tg3_flag_set(tp, TSO_CAPABLE); - netdev_update_features(dev); - } tg3_flag_clear(tp, JUMBO_RING_ENABLE); } } @@ -14119,6 +14115,14 @@ static int tg3_change_mtu(struct net_device *dev, int new_mtu) tg3_set_mtu(dev, tp, new_mtu); + tg3_full_unlock(tp); + + /* Adjusting MTU may add/remove TSO feature. */ + if (tg3_flag(tp, 5780_CLASS)) + netdev_update_features(dev); + + tg3_full_lock(tp, 0); + /* Reset PHY, otherwise the read DMA engine will be in a mode that * breaks all requests to 256 bytes. */ -- 1.7.2.5