Subject: Re: [PATCHv2] atm: nicstar: simplify allocation

From: Simon Horman <[email-masked]>
Date: Fri, 27 Mar 2026 11:38:23 +0000

On Wed, Mar 25, 2026 at 10:35:39PM -0700, Rosen Penev wrote:
> Use a flexible array member with kzalloc_flex to combine allocations
> into one.
> 
> Add __counted_by for extra runtime analysis. Move counting variable
> assignment to right after allocation as required by __counted_by.
> 
> Signed-off-by: Rosen Penev <[email-masked]>
> ---
>  v2: use kzalloc_flex
>  drivers/atm/nicstar.c | 17 +++++------------
>  drivers/atm/nicstar.h |  4 ++--
>  2 files changed, 7 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/atm/nicstar.c b/drivers/atm/nicstar.c
> index 24e51343df15..b01c6cfdcc87 100644
> --- a/drivers/atm/nicstar.c
> +++ b/drivers/atm/nicstar.c
> @@ -867,23 +867,17 @@ static scq_info *get_scq(ns_dev *card, int size, u32 scd)
>  	if (size != VBR_SCQSIZE && size != CBR_SCQSIZE)
>  		return NULL;
> 
> -	scq = kmalloc_obj(*scq);
> +	scq = kzalloc_flex(*scq, skb, size / NS_SCQE_SIZE);
>  	if (!scq)
>  		return NULL;
> -        scq->org = dma_alloc_coherent(&card->pcidev->dev,
> -				      2 * size,  &scq->dma, GFP_KERNEL);
> +
> +	scq->num_entries = size / NS_SCQE_SIZE;
> +
> +	scq->org = dma_alloc_coherent(&card->pcidev->dev, 2 * size, &scq->dma, GFP_KERNEL);

Networking still prefers code that is 80 columns wide or less:

	scq->org = dma_alloc_coherent(&card->pcidev->dev,
				      2 * size, &scq->dma, GFP_KERNEL);

But maybe just leave this line as it was?

...

> diff --git a/drivers/atm/nicstar.h b/drivers/atm/nicstar.h
> index 1b7f1dfc1735..ba45be53d40e 100644
> --- a/drivers/atm/nicstar.h
> +++ b/drivers/atm/nicstar.h
> @@ -667,14 +667,14 @@ typedef struct scq_info {
>  	ns_scqe *next;
>  	volatile ns_scqe *tail;	/* Not related to the nicstar register */
>  	unsigned num_entries;
> -	struct sk_buff **skb;	/* Pointer to an array of pointers
> -				   to the sk_buffs used for tx */
>  	u32 scd;		/* SRAM address of the corresponding
>  				   SCD */
>  	int tbd_count;		/* Only meaningful on variable rate */
>  	wait_queue_head_t scqfull_waitq;
>  	volatile char full;	/* SCQ full indicator */
>  	spinlock_t lock;	/* SCQ spinlock */
> +	struct sk_buff *skb[] __counted_by(num_entries);	/* Pointer to an array of pointers
> +								   to the sk_buffs used for tx */

Likewise, 80 columns wide here too.

>  } scq_info;
> 
>  typedef struct rsq_info {

-- 
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