[PATCH 3.16.y-ckt 156/168] net/mlx4_core: Limit count field to 24 bits in qp_alloc_res

From: Luis Henriques
Date: Mon Dec 15 2014 - 09:33:52 EST

3.16.7-ckt3 -stable review patch. If anyone has any objections, please let me know.


From: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>

commit 2d5c57d7fbfaa642fb7f0673df24f32b83d9066c upstream.

Some VF drivers use the upper byte of "param1" (the qp count field)
in mlx4_qp_reserve_range() to pass flags which are used to optimize
the range allocation.

Under the current code, if any of these flags are set, the 32-bit
count field yields a count greater than 2^24, which is out of range,
and this VF fails.

As these flags represent a "best-effort" allocation hint anyway, they may
safely be ignored. Therefore, the PF driver may simply mask out the bits.

Fixes: c82e9aa0a8 "mlx4_core: resource tracking for HCA resources used by guests"
Signed-off-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
drivers/net/ethernet/mellanox/mlx4/resource_tracker.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
index 0efc1368e5a8..9d14ed372c44 100644
--- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
+++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c
@@ -1532,7 +1532,7 @@ static int qp_alloc_res(struct mlx4_dev *dev, int slave, int op, int cmd,

switch (op) {
- count = get_param_l(&in_param);
+ count = get_param_l(&in_param) & 0xffffff;
align = get_param_h(&in_param);
err = mlx4_grant_resource(dev, slave, RES_QP, count, 0);
if (err)

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