linux-kernel - [PATCH 2/2] net/mlx4_core: clean up srq_res_start_move

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Date:	Tue, 07 Jan 2014 14:02:14 +0100
From:	Paul Bolle <pebolle@...cali.nl>
To:	Or Gerlitz <ogerlitz@...lanox.com>,
	Jack Morgenstein <jackm@....mellanox.co.il>,
	Rony Efraim <ronye@...lanox.com>,
	Hadar Hen Zion <hadarh@...lanox.com>,
	"David S. Miller" <davem@...emloft.net>
Cc:	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] net/mlx4_core: clean up srq_res_start_move_to()

Building resource_tracker.o triggers a GCC warning:
    drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_HW2SW_SRQ_wrapper':
    drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:3202:17: warning: 'srq' may be used uninitialized in this function [-Wmaybe-uninitialized]
      atomic_dec(&srq->mtt->ref_count);
                     ^

This is a false positive. But a cleanup of srq_res_start_move_to() can
help GCC here. The code currently uses a switch statement where a plain
if/else would do, since only two of the switch's four cases can ever
occur. Dropping that switch makes the warning go away.

While we're at it, do some coding style cleanups (missing braces),
convert state to the correct type, and drop a test that always evaluates
to true.

Signed-off-by: Paul Bolle <pebolle@...cali.nl>
---
 .../net/ethernet/mellanox/mlx4/resource_tracker.c  | 45 ++++++++--------------
 1 file changed, 16 insertions(+), 29 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
index a41f01e..8ace450 100644
--- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
+++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
@@ -1372,7 +1372,7 @@ static int cq_res_start_move_to(struct mlx4_dev *dev, int slave, int cqn,
 }
 
 static int srq_res_start_move_to(struct mlx4_dev *dev, int slave, int index,
-				 enum res_cq_states state, struct res_srq **srq)
+				 enum res_srq_states state, struct res_srq **srq)
 {
 	struct mlx4_priv *priv = mlx4_priv(dev);
 	struct mlx4_resource_tracker *tracker = &priv->mfunc.master.res_tracker;
@@ -1381,39 +1381,26 @@ static int srq_res_start_move_to(struct mlx4_dev *dev, int slave, int index,
 
 	spin_lock_irq(mlx4_tlock(dev));
 	r = res_tracker_lookup(&tracker->res_tree[RES_SRQ], index);
-	if (!r)
+	if (!r) {
 		err = -ENOENT;
-	else if (r->com.owner != slave)
+	} else if (r->com.owner != slave) {
 		err = -EPERM;
-	else {
-		switch (state) {
-		case RES_SRQ_BUSY:
+	} else if (state == RES_SRQ_ALLOCATED) {
+		if (r->com.state != RES_SRQ_HW)
 			err = -EINVAL;
-			break;
-
-		case RES_SRQ_ALLOCATED:
-			if (r->com.state != RES_SRQ_HW)
-				err = -EINVAL;
-			else if (atomic_read(&r->ref_count))
-				err = -EBUSY;
-			break;
-
-		case RES_SRQ_HW:
-			if (r->com.state != RES_SRQ_ALLOCATED)
-				err = -EINVAL;
-			break;
-
-		default:
+		else if (atomic_read(&r->ref_count))
+			err = -EBUSY;
+	} else {
+		/* state == RES_SRQ_HW */
+		if (r->com.state != RES_SRQ_ALLOCATED)
 			err = -EINVAL;
-		}
+	}
 
-		if (!err) {
-			r->com.from_state = r->com.state;
-			r->com.to_state = state;
-			r->com.state = RES_SRQ_BUSY;
-			if (srq)
-				*srq = r;
-		}
+	if (!err) {
+		r->com.from_state = r->com.state;
+		r->com.to_state = state;
+		r->com.state = RES_SRQ_BUSY;
+		*srq = r;
 	}
 
 	spin_unlock_irq(mlx4_tlock(dev));
-- 
1.8.4.2

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