From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yevgeny Petrilin Subject: [PATCH net] mlx4_core: fix race on comm channel Date: Sun, 18 Mar 2012 14:18:07 +0200 Message-ID: <4F65D27F.7010102@mellanox.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: , , To: Return-path: Received: from eu1sys200aog103.obsmtp.com ([207.126.144.115]:36016 "HELO eu1sys200aog103.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751087Ab2CRMSN (ORCPT ); Sun, 18 Mar 2012 08:18:13 -0400 Sender: netdev-owner@vger.kernel.org List-ID: From: Eugenia Emantayev Prevent race condition between commands on comm channel. Happened while unloading the driver when switching from event to polling mode. VF got completion on the last command before switching to polling mode, but toggle was not changed. After the fix - VF will not write the next command before toggle is updated. Signed-off-by: Eugenia Emantayev --- drivers/net/ethernet/mellanox/mlx4/cmd.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c index eaf09d4..2f1f4a1 100644 --- a/drivers/net/ethernet/mellanox/mlx4/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c @@ -239,6 +239,7 @@ static int mlx4_comm_cmd_wait(struct mlx4_dev *dev, u8 op, { struct mlx4_cmd *cmd = &mlx4_priv(dev)->cmd; struct mlx4_cmd_context *context; + unsigned long end; int err = 0; down(&cmd->event_sem); @@ -268,6 +269,13 @@ static int mlx4_comm_cmd_wait(struct mlx4_dev *dev, u8 op, } out: + /* wait for comm channel ready + this is necessary for prevention the race + when switching between event to polling mode */ + end = msecs_to_jiffies(timeout) + jiffies; + while (comm_pending(dev) && time_before(jiffies, end)) + cond_resched(); + spin_lock(&cmd->context_lock); context->next = cmd->free_head; cmd->free_head = context - cmd->context; -- 1.7.7