diff options
| author | Liming Sun <limings@nvidia.com> | 2021-05-07 20:30:12 -0400 |
|---|---|---|
| committer | Hans de Goede <hdegoede@redhat.com> | 2021-05-19 15:24:52 +0200 |
| commit | 1c0e5701c5e792c090aef0e5b9b8923c334d9324 (patch) | |
| tree | da8834c666b89c3898ced373638c25a2dcbf9e4c /drivers/platform | |
| parent | 9795d8232a24be9e1e1cc408a6bdc01c40e2cedc (diff) | |
platform/mellanox: mlxbf-tmfifo: Fix a memory barrier issue
The virtio framework uses wmb() when updating avail->idx. It
guarantees the write order, but not necessarily loading order
for the code accessing the memory. This commit adds a load barrier
after reading the avail->idx to make sure all the data in the
descriptor is visible. It also adds a barrier when returning the
packet to virtio framework to make sure read/writes are visible to
the virtio code.
Fixes: 1357dfd7261f ("platform/mellanox: Add TmFifo driver for Mellanox BlueField Soc")
Signed-off-by: Liming Sun <limings@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://lore.kernel.org/r/1620433812-17911-1-git-send-email-limings@nvidia.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Diffstat (limited to 'drivers/platform')
| -rw-r--r-- | drivers/platform/mellanox/mlxbf-tmfifo.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c index bbc4e71a16ff..38800e86ed8a 100644 --- a/drivers/platform/mellanox/mlxbf-tmfifo.c +++ b/drivers/platform/mellanox/mlxbf-tmfifo.c @@ -294,6 +294,9 @@ mlxbf_tmfifo_get_next_desc(struct mlxbf_tmfifo_vring *vring) if (vring->next_avail == virtio16_to_cpu(vdev, vr->avail->idx)) return NULL; + /* Make sure 'avail->idx' is visible already. */ + virtio_rmb(false); + idx = vring->next_avail % vr->num; head = virtio16_to_cpu(vdev, vr->avail->ring[idx]); if (WARN_ON(head >= vr->num)) @@ -322,7 +325,7 @@ static void mlxbf_tmfifo_release_desc(struct mlxbf_tmfifo_vring *vring, * done or not. Add a memory barrier here to make sure the update above * completes before updating the idx. */ - mb(); + virtio_mb(false); vr->used->idx = cpu_to_virtio16(vdev, vr_idx + 1); } @@ -733,6 +736,12 @@ static bool mlxbf_tmfifo_rxtx_one_desc(struct mlxbf_tmfifo_vring *vring, desc = NULL; fifo->vring[is_rx] = NULL; + /* + * Make sure the load/store are in order before + * returning back to virtio. + */ + virtio_mb(false); + /* Notify upper layer that packet is done. */ spin_lock_irqsave(&fifo->spin_lock[is_rx], flags); vring_interrupt(0, vring->vq); |