netdev - Re: [PATCH] mlx5/core: remove mlx5_core_cq.tasklet

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Message-ID: <90e5e7d6-89c5-4f0f-9a9d-34873fc498ad@intel.com>
Date: Tue, 19 Nov 2024 15:53:39 -0800
From: Jacob Keller <jacob.e.keller@...el.com>
To: Caleb Sander Mateos <csander@...estorage.com>, Saeed Mahameed
	<saeedm@...dia.com>, Leon Romanovsky <leon@...nel.org>, Tariq Toukan
	<tariqt@...dia.com>, Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller"
	<davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski
	<kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
CC: <netdev@...r.kernel.org>, <linux-rdma@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mlx5/core: remove mlx5_core_cq.tasklet_ctx.priv field



On 11/18/2024 8:24 PM, Caleb Sander Mateos wrote:
> The priv field in mlx5_core_cq's tasklet_ctx struct points to the
> mlx5_eq_tasklet tasklet_ctx field of the CQ's mlx5_eq_comp. mlx5_core_cq
> already stores a pointer to the EQ. Use this eq pointer to get a pointer
> to the tasklet_ctx with no additional pointer dereferences and no void *
> casts. Remove the now unused priv field.
> 
> Signed-off-by: Caleb Sander Mateos <csander@...estorage.com>
> ---

This needs to tag net-next, as it doesn't fix any user-visible bug.
Additionally, net-next just closed for preparation of 6.13, and this
will need to wait until it re-opens on Dec 2nd.

The code change itself seems reasonable to me, saving an otherwise
unnecessary pointer.

When you resend it when the window is open, feel free to add:

Reviewed-by: Jacob Keller <jacob.e.keller@...el.com>

Thanks,
Jake

>  drivers/net/ethernet/mellanox/mlx5/core/cq.c | 5 ++---
>  include/linux/mlx5/cq.h                      | 1 -
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cq.c b/drivers/net/ethernet/mellanox/mlx5/core/cq.c
> index 1fd403713baf..dc5a291f0993 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/cq.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/cq.c
> @@ -68,11 +68,11 @@ void mlx5_cq_tasklet_cb(struct tasklet_struct *t)
>  
>  static void mlx5_add_cq_to_tasklet(struct mlx5_core_cq *cq,
>  				   struct mlx5_eqe *eqe)
>  {
>  	unsigned long flags;
> -	struct mlx5_eq_tasklet *tasklet_ctx = cq->tasklet_ctx.priv;
> +	struct mlx5_eq_tasklet *tasklet_ctx = &cq->eq->tasklet_ctx;
>  	bool schedule_tasklet = false;
>  
>  	spin_lock_irqsave(&tasklet_ctx->lock, flags);
>  	/* When migrating CQs between EQs will be implemented, please note
>  	 * that you need to sync this point. It is possible that
> @@ -117,18 +117,17 @@ int mlx5_create_cq(struct mlx5_core_dev *dev, struct mlx5_core_cq *cq,
>  		return err;
>  
>  	cq->cqn = MLX5_GET(create_cq_out, out, cqn);
>  	cq->cons_index = 0;
>  	cq->arm_sn     = 0;
> +	/* assuming CQ will be deleted before the EQ */
>  	cq->eq         = eq;
>  	cq->uid = MLX5_GET(create_cq_in, in, uid);
>  	refcount_set(&cq->refcount, 1);
>  	init_completion(&cq->free);
>  	if (!cq->comp)
>  		cq->comp = mlx5_add_cq_to_tasklet;
> -	/* assuming CQ will be deleted before the EQ */
> -	cq->tasklet_ctx.priv = &eq->tasklet_ctx;
>  	INIT_LIST_HEAD(&cq->tasklet_ctx.list);
>  
>  	/* Add to comp EQ CQ tree to recv comp events */
>  	err = mlx5_eq_add_cq(&eq->core, cq);
>  	if (err)
> diff --git a/include/linux/mlx5/cq.h b/include/linux/mlx5/cq.h
> index 991526039ccb..cd034ea0ee34 100644
> --- a/include/linux/mlx5/cq.h
> +++ b/include/linux/mlx5/cq.h
> @@ -53,11 +53,10 @@ struct mlx5_core_cq {
>  	struct mlx5_rsc_debug	*dbg;
>  	int			pid;
>  	struct {
>  		struct list_head list;
>  		void (*comp)(struct mlx5_core_cq *cq, struct mlx5_eqe *eqe);
> -		void		*priv;
>  	} tasklet_ctx;
>  	int			reset_notify_added;
>  	struct list_head	reset_notify;
>  	struct mlx5_eq_comp	*eq;
>  	u16 uid;