[PATCH 3.19.y-ckt 152/155] net/mlx4: Copy/set only sizeof struct mlx4_eqe bytes

From: Kamal Mostafa
Date: Thu Nov 12 2015 - 18:20:44 EST

3.19.8-ckt10 -stable review patch. If anyone has any objections, please let me know.


From: Carol L Soto <clsoto@xxxxxxxxxxxxxxxxxx>

commit c02b05011fadf8e409e41910217ca689f2fc9d91 upstream.

When doing memcpy/memset of EQEs, we should use sizeof struct
mlx4_eqe as the base size and not caps.eqe_size which could be bigger.

If caps.eqe_size is bigger than the struct mlx4_eqe then we corrupt
data in the master context.

When using a 64 byte stride, the memcpy copied over 63 bytes to the
slave_eq structure. This resulted in copying over the entire eqe of
interest, including its ownership bit -- and also 31 bytes of garbage
into the next WQE in the slave EQ -- which did NOT include the ownership
bit (and therefore had no impact).

However, once the stride is increased to 128, we are overwriting the
ownership bits of *three* eqes in the slave_eq struct. This results
in an incorrect ownership bit for those eqes, which causes the eq to
seem to be full. The issue therefore surfaced only once 128-byte EQEs
started being used in SRIOV and (overarchitectures that have 128/256
byte cache-lines such as PPC) - e.g after commit 77507aa249ae
"net/mlx4_core: Enable CQE/EQE stride support".

Fixes: 08ff32352d6f ('mlx4: 64-byte CQE/EQE support')
Signed-off-by: Carol L Soto <clsoto@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
drivers/net/ethernet/mellanox/mlx4/cmd.c | 2 +-
drivers/net/ethernet/mellanox/mlx4/eq.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c
index 782bd10..9629383 100644
--- a/drivers/net/ethernet/mellanox/mlx4/cmd.c
+++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c
@@ -2058,7 +2058,7 @@ int mlx4_multi_func_init(struct mlx4_dev *dev)

- memset(&priv->mfunc.master.cmd_eqe, 0, dev->caps.eqe_size);
+ memset(&priv->mfunc.master.cmd_eqe, 0, sizeof(struct mlx4_eqe));
priv->mfunc.master.cmd_eqe.type = MLX4_EVENT_TYPE_CMD;
diff --git a/drivers/net/ethernet/mellanox/mlx4/eq.c b/drivers/net/ethernet/mellanox/mlx4/eq.c
index 5d2f56a..c7c67a1 100644
--- a/drivers/net/ethernet/mellanox/mlx4/eq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/eq.c
@@ -185,7 +185,7 @@ static void slave_event(struct mlx4_dev *dev, u8 slave, struct mlx4_eqe *eqe)

- memcpy(s_eqe, eqe, dev->caps.eqe_size - 1);
+ memcpy(s_eqe, eqe, sizeof(struct mlx4_eqe) - 1);
s_eqe->slave_id = slave;
/* ensure all information is written before setting the ownersip bit */

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