linux-kernel - [PATCH] IB/mlx4: avoid a -Wmaybe-uninitialize warning

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Date:   Tue, 25 Oct 2016 18:16:20 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Yishai Hadas <yishaih@...lanox.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        "David S. Miller" <davem@...emloft.net>,
        Jack Morgenstein <jackm@....mellanox.co.il>,
        Or Gerlitz <ogerlitz@...lanox.com>,
        Eran Ben Elisha <eranbe@...lanox.com>,
        Moshe Shemesh <moshe@...lanox.com>,
        Christophe Jaillet <christophe.jaillet@...adoo.fr>,
        Moni Shoua <monis@...lanox.com>, netdev@...r.kernel.org,
        linux-rdma@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] IB/mlx4: avoid a -Wmaybe-uninitialize warning

There is an old warning about mlx4_SW2HW_EQ_wrapper on x86:

ethernet/mellanox/mlx4/resource_tracker.c: In function ‘mlx4_SW2HW_EQ_wrapper’:
ethernet/mellanox/mlx4/resource_tracker.c:3071:10: error: ‘eq’ may be used uninitialized in this function [-Werror=maybe-uninitialized]

The problem here is that gcc won't track the state of the variable
across a spin_unlock. Moving the assignment out of the lock is
safe here and avoids the warning.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/net/ethernet/mellanox/mlx4/resource_tracker.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
index 84d7857ccc27..c548beaaf910 100644
--- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
+++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
@@ -1605,13 +1605,14 @@ static int eq_res_start_move_to(struct mlx4_dev *dev, int slave, int index,
 			r->com.from_state = r->com.state;
 			r->com.to_state = state;
 			r->com.state = RES_EQ_BUSY;
-			if (eq)
-				*eq = r;
 		}
 	}
 
 	spin_unlock_irq(mlx4_tlock(dev));
 
+	if (!err && eq)
+		*eq = r;
+
 	return err;
 }
 
-- 
2.9.0