net/mlx4_core: clean up srq_res_start_move_to()

drivers/net/ethernet/mellanox/mlx4/resource_tracker.c +1 -2

 			err = -EINVAL;
-		}
+	}
 
-		if (!err) {

drivers/net/ethernet/mellanox/mlx4/resource_tracker.c +1 -0

+		*srq = r;
 	}
 
 	spin_unlock_irq(mlx4_tlock(dev));

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, add some missing braces, and convert state to the correct type.

Signed-off-by Paul Bolle <[email protected]>

---
v2: adjust to Jack's review.

 .../net/ethernet/mellanox/mlx4/resource_tracker.c  | 46

++++++++-------------- 1 file changed, 16 insertions(+), 30 deletions(-)

(quoted diff) +0 -0

b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c index 15cd659..4acd84c 100644 --- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c +++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c @@ -1371,7 +1371,7 @@ 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,

(quoted diff) +0 -1

-				 enum res_cq_states state, struct

res_srq **srq)

(quoted diff) +1 -0

+				 enum res_srq_states state, struct

res_srq **srq) {

(quoted diff) +0 -0

 	struct mlx4_priv *priv = mlx4_priv(dev);
 	struct mlx4_resource_tracker *tracker =

&priv->mfunc.master.res_tracker; @@ -1380,39 +1380,25 @@ static int srq_res_start_move_to(struct mlx4_dev *dev, int slave, int index,

drivers/net/ethernet/mellanox/mlx4/resource_tracker.c +7 -22

 	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:
-			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 (state == RES_SRQ_ALLOCATED) {
+		if (r->com.state != RES_SRQ_HW)
 			err = -EINVAL;
-		}
+		else if (atomic_read(&r->ref_count))
+			err = -EBUSY;
+	} else if (state != RES_SRQ_HW || r->com.state !=

RES_SRQ_ALLOCATED) {

drivers/net/ethernet/mellanox/mlx4/resource_tracker.c +8 -7

+		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;
+		if (srq)
+			*srq = r;
 	}
 
 	spin_unlock_irq(mlx4_tlock(dev));

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, add some missing braces, and convert state to the correct type.

Signed-off-by Paul Bolle <[email protected]>