RE: [PATCH v3 1/9] NTB: Make link-state API being declared first

["Allen Hubbe" <Allen.Hubbe@dell.com>]

From: Serge Semin 
> Since link operations are usually performed before memory window access
> operations, it's logically better to declare link-related API before any
> of MW/Doorbell/Scratchpad methods.
> 
> Signed-off-by: Serge Semin <fancer.lancer@gmail.com>

Acked-by: Allen Hubbe <Allen.Hubbe@dell.com>

> ---
>  include/linux/ntb.h | 137 ++++++++++++++++++++++++++--------------------------
>  1 file changed, 69 insertions(+), 68 deletions(-)
> 
> diff --git a/include/linux/ntb.h b/include/linux/ntb.h
> index 6f47562..5d1f260 100644
> --- a/include/linux/ntb.h
> +++ b/include/linux/ntb.h
> @@ -179,13 +179,13 @@ static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops
> *ops)
> 
>  /**
>   * struct ntb_ctx_ops - ntb device operations
> + * @link_is_up:		See ntb_link_is_up().
> + * @link_enable:	See ntb_link_enable().
> + * @link_disable:	See ntb_link_disable().
>   * @mw_count:		See ntb_mw_count().
>   * @mw_get_range:	See ntb_mw_get_range().
>   * @mw_set_trans:	See ntb_mw_set_trans().
>   * @mw_clear_trans:	See ntb_mw_clear_trans().
> - * @link_is_up:		See ntb_link_is_up().
> - * @link_enable:	See ntb_link_enable().
> - * @link_disable:	See ntb_link_disable().
>   * @db_is_unsafe:	See ntb_db_is_unsafe().
>   * @db_valid_mask:	See ntb_db_valid_mask().
>   * @db_vector_count:	See ntb_db_vector_count().
> @@ -212,6 +212,12 @@ static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops)
>   * @peer_spad_write:	See ntb_peer_spad_write().
>   */
>  struct ntb_dev_ops {
> +	int (*link_is_up)(struct ntb_dev *ntb,
> +			  enum ntb_speed *speed, enum ntb_width *width);
> +	int (*link_enable)(struct ntb_dev *ntb,
> +			   enum ntb_speed max_speed, enum ntb_width max_width);
> +	int (*link_disable)(struct ntb_dev *ntb);
> +
>  	int (*mw_count)(struct ntb_dev *ntb);
>  	int (*mw_get_range)(struct ntb_dev *ntb, int idx,
>  			    phys_addr_t *base, resource_size_t *size,
> @@ -220,12 +226,6 @@ struct ntb_dev_ops {
>  			    dma_addr_t addr, resource_size_t size);
>  	int (*mw_clear_trans)(struct ntb_dev *ntb, int idx);
> 
> -	int (*link_is_up)(struct ntb_dev *ntb,
> -			  enum ntb_speed *speed, enum ntb_width *width);
> -	int (*link_enable)(struct ntb_dev *ntb,
> -			   enum ntb_speed max_speed, enum ntb_width max_width);
> -	int (*link_disable)(struct ntb_dev *ntb);
> -
>  	int (*db_is_unsafe)(struct ntb_dev *ntb);
>  	u64 (*db_valid_mask)(struct ntb_dev *ntb);
>  	int (*db_vector_count)(struct ntb_dev *ntb);
> @@ -265,13 +265,14 @@ static inline int ntb_dev_ops_is_valid(const struct ntb_dev_ops
> *ops)
>  {
>  	/* commented callbacks are not required: */
>  	return
> +		ops->link_is_up				&&
> +		ops->link_enable			&&
> +		ops->link_disable			&&
>  		ops->mw_count				&&
>  		ops->mw_get_range			&&
>  		ops->mw_set_trans			&&
>  		/* ops->mw_clear_trans			&& */
> -		ops->link_is_up				&&
> -		ops->link_enable			&&
> -		ops->link_disable			&&
> +
>  		/* ops->db_is_unsafe			&& */
>  		ops->db_valid_mask			&&
> 
> @@ -441,6 +442,62 @@ void ntb_link_event(struct ntb_dev *ntb);
>  void ntb_db_event(struct ntb_dev *ntb, int vector);
> 
>  /**
> + * ntb_link_is_up() - get the current ntb link state
> + * @ntb:	NTB device context.
> + * @speed:	OUT - The link speed expressed as PCIe generation number.
> + * @width:	OUT - The link width expressed as the number of PCIe lanes.
> + *
> + * Get the current state of the ntb link.  It is recommended to query the link
> + * state once after every link event.  It is safe to query the link state in
> + * the context of the link event callback.
> + *
> + * Return: One if the link is up, zero if the link is down, otherwise a
> + *		negative value indicating the error number.
> + */
> +static inline int ntb_link_is_up(struct ntb_dev *ntb,
> +				 enum ntb_speed *speed, enum ntb_width *width)
> +{
> +	return ntb->ops->link_is_up(ntb, speed, width);
> +}
> +
> +/**
> + * ntb_link_enable() - enable the link on the secondary side of the ntb
> + * @ntb:	NTB device context.
> + * @max_speed:	The maximum link speed expressed as PCIe generation number.
> + * @max_width:	The maximum link width expressed as the number of PCIe lanes.
> + *
> + * Enable the link on the secondary side of the ntb.  This can only be done
> + * from the primary side of the ntb in primary or b2b topology.  The ntb device
> + * should train the link to its maximum speed and width, or the requested speed
> + * and width, whichever is smaller, if supported.
> + *
> + * Return: Zero on success, otherwise an error number.
> + */
> +static inline int ntb_link_enable(struct ntb_dev *ntb,
> +				  enum ntb_speed max_speed,
> +				  enum ntb_width max_width)
> +{
> +	return ntb->ops->link_enable(ntb, max_speed, max_width);
> +}
> +
> +/**
> + * ntb_link_disable() - disable the link on the secondary side of the ntb
> + * @ntb:	NTB device context.
> + *
> + * Disable the link on the secondary side of the ntb.  This can only be
> + * done from the primary side of the ntb in primary or b2b topology.  The ntb
> + * device should disable the link.  Returning from this call must indicate that
> + * a barrier has passed, though with no more writes may pass in either
> + * direction across the link, except if this call returns an error number.
> + *
> + * Return: Zero on success, otherwise an error number.
> + */
> +static inline int ntb_link_disable(struct ntb_dev *ntb)
> +{
> +	return ntb->ops->link_disable(ntb);
> +}
> +
> +/**
>   * ntb_mw_count() - get the number of memory windows
>   * @ntb:	NTB device context.
>   *
> @@ -517,62 +574,6 @@ static inline int ntb_mw_clear_trans(struct ntb_dev *ntb, int idx)
>  }
> 
>  /**
> - * ntb_link_is_up() - get the current ntb link state
> - * @ntb:	NTB device context.
> - * @speed:	OUT - The link speed expressed as PCIe generation number.
> - * @width:	OUT - The link width expressed as the number of PCIe lanes.
> - *
> - * Get the current state of the ntb link.  It is recommended to query the link
> - * state once after every link event.  It is safe to query the link state in
> - * the context of the link event callback.
> - *
> - * Return: One if the link is up, zero if the link is down, otherwise a
> - *		negative value indicating the error number.
> - */
> -static inline int ntb_link_is_up(struct ntb_dev *ntb,
> -				 enum ntb_speed *speed, enum ntb_width *width)
> -{
> -	return ntb->ops->link_is_up(ntb, speed, width);
> -}
> -
> -/**
> - * ntb_link_enable() - enable the link on the secondary side of the ntb
> - * @ntb:	NTB device context.
> - * @max_speed:	The maximum link speed expressed as PCIe generation number.
> - * @max_width:	The maximum link width expressed as the number of PCIe lanes.
> - *
> - * Enable the link on the secondary side of the ntb.  This can only be done
> - * from the primary side of the ntb in primary or b2b topology.  The ntb device
> - * should train the link to its maximum speed and width, or the requested speed
> - * and width, whichever is smaller, if supported.
> - *
> - * Return: Zero on success, otherwise an error number.
> - */
> -static inline int ntb_link_enable(struct ntb_dev *ntb,
> -				  enum ntb_speed max_speed,
> -				  enum ntb_width max_width)
> -{
> -	return ntb->ops->link_enable(ntb, max_speed, max_width);
> -}
> -
> -/**
> - * ntb_link_disable() - disable the link on the secondary side of the ntb
> - * @ntb:	NTB device context.
> - *
> - * Disable the link on the secondary side of the ntb.  This can only be
> - * done from the primary side of the ntb in primary or b2b topology.  The ntb
> - * device should disable the link.  Returning from this call must indicate that
> - * a barrier has passed, though with no more writes may pass in either
> - * direction across the link, except if this call returns an error number.
> - *
> - * Return: Zero on success, otherwise an error number.
> - */
> -static inline int ntb_link_disable(struct ntb_dev *ntb)
> -{
> -	return ntb->ops->link_disable(ntb);
> -}
> -
> -/**
>   * ntb_db_is_unsafe() - check if it is safe to use hardware doorbell
>   * @ntb:	NTB device context.
>   *
> --
> 2.6.6