net/mlx5e: RX, Avoid possible data corruption when relaxed ordering and LRO combined

Browse source

When HW aggregates packets for an LRO session, it writes the payload
of two consecutive packets of a flow contiguously, so that they usually
share a cacheline.

The first byte of a packet's payload is written immediately after
the last byte of the preceding packet.
In this flow, there are two consecutive write requests to the shared
cacheline:
1. Regular write for the earlier packet.
2. Read-modify-write for the following packet.

In case of relaxed-ordering on, these two writes might be re-ordered.
Using the end padding optimization (to avoid partial write for the last
cacheline of a packet) becomes problematic if the two writes occur
out-of-order, as the padding would overwrite payload that belongs to
the following packet, causing data corruption.

Avoid this by disabling the end padding optimization when both
LRO and relaxed-ordering are enabled.

Fixes: 17347d5430 ("net/mlx5e: Add support for PCI relaxed ordering")
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

...

This commit is contained in:

Tariq Toukan 2021-06-30 13:45:05 +03:00 • committed by Saeed Mahameed

parent dd3fddb827

commit e2351e5170

1 changed files with 10 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

11

drivers/net/ethernet/mellanox/mlx5/core/en/params.c

View file