ACK: [SRU][FOCAL][PATCH v2 0/1] net/mlx5: Fix a race when moving command interface to polling mode

Marcelo Henrique Cerri marcelo.cerri at canonical.com
Fri Jan 22 16:38:08 UTC 2021


It looks good for me. Bionic is not affected and Groovy already has
the same fix.

Acked-by: Marcelo Henrique Cerri <marcelo.cerri at canonical.com>

On Tue, Jan 19, 2021 at 11:07:26AM -0500, William Breathitt Gray wrote:
> Changes in v2:
>  - Fix typo in commit "cherry pick" line
> 
> [Impact]
> 
> As part of driver unload, it destroys the commands EQ (via FW command).
> As the commands EQ is destroyed, FW will not generate EQEs for any command
> that driver sends afterwards. Driver should poll for later commands status.
> 
> Driver commands mode metadata is updated before the commands EQ is
> actually destroyed. This can lead for double completion handle by the
> driver (polling and interrupt), if a command is executed and completed by
> FW after the mode was changed, but before the EQ was destroyed.
> 
> [Fix]
> 
> Fix that by using the mlx5_cmd_allowed_opcode mechanism to guarantee
> that only DESTROY_EQ command can be executed during this time period.
> 
> [Where problems could occur]
> 
> The scope of the changes in this patch is narrow: only the
> destroy_async_eqs() function is touched. If a problem occurs, it will
> occur during the small window when the driver unloads. Regression
> potential is low however because only the DESTROY_EQ command should
> execute during this time period.
> 
> Eran Ben Elisha (1):
>   net/mlx5: Fix a race when moving command interface to polling mode
> 
>  drivers/net/ethernet/mellanox/mlx5/core/eq.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> -- 
> 2.27.0
> 
> 
> -- 
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> kernel-team at lists.ubuntu.com
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-- 
Regards,
Marcelo

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