[PATCH 4.2 30/30] net/mlx4_core: Capping number of requested MSIXs to MAX_MSIX

[Greg Kroah-Hartman]

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Carol L Soto <clsoto@xxxxxxxxxxxxxxxxxx>

[ Upstream commit 9293267a3e2a7a2555d8ddc8f9301525e5b03b1b ]

We currently manage IRQs in pool_bm which is a bit field
of MAX_MSIX bits. Thus, allocating more than MAX_MSIX
interrupts can't be managed in pool_bm.
Fixing this by capping number of requested MSIXs to
MAX_MSIX.

Signed-off-by: Matan Barak <matanb@xxxxxxxxxxxx>
Signed-off-by: Carol L Soto <clsoto@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx4/main.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -2654,9 +2654,14 @@ static void mlx4_enable_msi_x(struct mlx
 
 	if (msi_x) {
 		int nreq = dev->caps.num_ports * num_online_cpus() + 1;
+		bool shared_ports = false;
 
 		nreq = min_t(int, dev->caps.num_eqs - dev->caps.reserved_eqs,
 			     nreq);
+		if (nreq > MAX_MSIX) {
+			nreq = MAX_MSIX;
+			shared_ports = true;
+		}
 
 		entries = kcalloc(nreq, sizeof *entries, GFP_KERNEL);
 		if (!entries)
@@ -2679,6 +2684,9 @@ static void mlx4_enable_msi_x(struct mlx
 		bitmap_zero(priv->eq_table.eq[MLX4_EQ_ASYNC].actv_ports.ports,
 			    dev->caps.num_ports);
 
+		if (MLX4_IS_LEGACY_EQ_MODE(dev->caps))
+			shared_ports = true;
+
 		for (i = 0; i < dev->caps.num_comp_vectors + 1; i++) {
 			if (i == MLX4_EQ_ASYNC)
 				continue;
@@ -2686,7 +2694,7 @@ static void mlx4_enable_msi_x(struct mlx
 			priv->eq_table.eq[i].irq =
 				entries[i + 1 - !!(i > MLX4_EQ_ASYNC)].vector;
 
-			if (MLX4_IS_LEGACY_EQ_MODE(dev->caps)) {
+			if (shared_ports) {
 				bitmap_fill(priv->eq_table.eq[i].actv_ports.ports,
 					    dev->caps.num_ports);
 				/* We don't set affinity hint when there


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