Re: [PATCH v3 1/8] powerpc/xive: introduce a common routine xive_queue_page_alloc()

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Wed, 2017-08-30 at 21:46 +0200, Cédric Le Goater wrote:
> This routine will be used in the spapr backend. Also introduce a short
> xive_alloc_order() helper.
> 
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

> ---
>  arch/powerpc/sysdev/xive/common.c        | 16 ++++++++++++++++
>  arch/powerpc/sysdev/xive/native.c        | 16 +++++-----------
>  arch/powerpc/sysdev/xive/xive-internal.h |  6 ++++++
>  3 files changed, 27 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c
> index 6e0c9dee724f..26999ceae20e 100644
> --- a/arch/powerpc/sysdev/xive/common.c
> +++ b/arch/powerpc/sysdev/xive/common.c
> @@ -1424,6 +1424,22 @@ bool xive_core_init(const struct xive_ops *ops, void __iomem *area, u32 offset,
>  	return true;
>  }
>  
> +__be32 *xive_queue_page_alloc(unsigned int cpu, u32 queue_shift)
> +{
> +	unsigned int alloc_order;
> +	struct page *pages;
> +	__be32 *qpage;
> +
> +	alloc_order = xive_alloc_order(queue_shift);
> +	pages = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, alloc_order);
> +	if (!pages)
> +		return ERR_PTR(-ENOMEM);
> +	qpage = (__be32 *)page_address(pages);
> +	memset(qpage, 0, 1 << queue_shift);
> +
> +	return qpage;
> +}
> +
>  static int __init xive_off(char *arg)
>  {
>  	xive_cmdline_disabled = true;
> diff --git a/arch/powerpc/sysdev/xive/native.c b/arch/powerpc/sysdev/xive/native.c
> index 0f95476b01f6..ef92a83090e1 100644
> --- a/arch/powerpc/sysdev/xive/native.c
> +++ b/arch/powerpc/sysdev/xive/native.c
> @@ -202,17 +202,12 @@ EXPORT_SYMBOL_GPL(xive_native_disable_queue);
>  static int xive_native_setup_queue(unsigned int cpu, struct xive_cpu *xc, u8 prio)
>  {
>  	struct xive_q *q = &xc->queue[prio];
> -	unsigned int alloc_order;
> -	struct page *pages;
>  	__be32 *qpage;
>  
> -	alloc_order = (xive_queue_shift > PAGE_SHIFT) ?
> -		(xive_queue_shift - PAGE_SHIFT) : 0;
> -	pages = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL, alloc_order);
> -	if (!pages)
> -		return -ENOMEM;
> -	qpage = (__be32 *)page_address(pages);
> -	memset(qpage, 0, 1 << xive_queue_shift);
> +	qpage = xive_queue_page_alloc(cpu, xive_queue_shift);
> +	if (IS_ERR(qpage))
> +		return PTR_ERR(qpage);
> +
>  	return xive_native_configure_queue(get_hard_smp_processor_id(cpu),
>  					   q, prio, qpage, xive_queue_shift, false);
>  }
> @@ -227,8 +222,7 @@ static void xive_native_cleanup_queue(unsigned int cpu, struct xive_cpu *xc, u8
>  	 * from an IPI and iounmap isn't safe
>  	 */
>  	__xive_native_disable_queue(get_hard_smp_processor_id(cpu), q, prio);
> -	alloc_order = (xive_queue_shift > PAGE_SHIFT) ?
> -		(xive_queue_shift - PAGE_SHIFT) : 0;
> +	alloc_order = xive_alloc_order(xive_queue_shift);
>  	free_pages((unsigned long)q->qpage, alloc_order);
>  	q->qpage = NULL;
>  }
> diff --git a/arch/powerpc/sysdev/xive/xive-internal.h b/arch/powerpc/sysdev/xive/xive-internal.h
> index d07ef2d29caf..dd1e2022cce4 100644
> --- a/arch/powerpc/sysdev/xive/xive-internal.h
> +++ b/arch/powerpc/sysdev/xive/xive-internal.h
> @@ -56,6 +56,12 @@ struct xive_ops {
>  
>  bool xive_core_init(const struct xive_ops *ops, void __iomem *area, u32 offset,
>  		    u8 max_prio);
> +__be32 *xive_queue_page_alloc(unsigned int cpu, u32 queue_shift);
> +
> +static inline u32 xive_alloc_order(u32 queue_shift)
> +{
> +	return (queue_shift > PAGE_SHIFT) ? (queue_shift - PAGE_SHIFT) : 0;
> +}
>  
>  extern bool xive_cmdline_disabled;
>