Re: [PATCH v9 0/2] IB/mlx5: Fix loopback rollback and locking

[Leon Romanovsky <leon@kernel.org>]

On Fri, Apr 10, 2026 at 01:52:16AM +0100, Prathamesh Deshpande wrote:
> This series fixes transport-domain rollback and loopback state
> consistency in mlx5 IB.
> 
> Patch 1 fixes TD rollback on mlx5_ib_enable_lb() failure, makes the
> success return path explicit, and initializes lb.mutex earlier.
> 
> Patch 2 serializes MP force-enable state updates with lb.mutex and
> implements capability-aware thresholds (td_base) to ensure correct
> loopback behavior on both TD-capable and no-TD hardware.
> 
> v9:
> - Address race/state issues around force_enable and enabled.
> - Fix TD leak on failure after successful allocation.
> - Implement hardware-aware thresholds via mlx5_ib_lb_td_base() to
>   handle both TD-capable and no-TD hardware correctly.
> - Serialize MP force-enable transitions under lb.mutex.
> 
> v8:
> - Resubmitted as a fresh, independent thread per maintainer request.
> - No functional changes since v7.
> 
> v7:
> - Split the series into two patches to isolate the return-value/mutex 
>   initialization fix from the refcounting logic.
> - Moved force_enable check after increments/decrements to fix leaks.
> - Updated hardware disable condition to a strict zero-check.
> 
> v1-v6:
> - Initial combined versions.
> - Added deallocation of tdn on failure.
> - Moved mutex_init to stage_init_init to prevent crashes on non-ETH.
> - Implemented atomic rollback in enable/disable paths.
> 
> Prathamesh Deshpande (2):
>   IB/mlx5: Fix transport-domain rollback and initialize lb mutex earlier

I agree that this patch is needed.

>   IB/mlx5: Serialize force-enable state and preserve loopback accounting

This change does not appear to be justified. The commit message provides no
clear explanation of why it is needed.

Thanks

> 
>  drivers/infiniband/hw/mlx5/main.c | 81 +++++++++++++++++++++++--------
>  1 file changed, 62 insertions(+), 19 deletions(-)
> 
> -- 
> 2.43.0
>