Re: [PATCH v2 1/6] scsi: libsas: Add LIBSAS_SHT_BASE

[Igor Pylypiv <ipylypiv@google.com>]

On Fri, Mar 08, 2024 at 11:43:34AM +0000, John Garry wrote:
> There is much duplication in the scsi_host_template structure for the
> drivers which use libsas.
> 
> Similar to how a standard template is used in libata with __ATA_BASE_SHT,
> create a standard template in LIBSAS_SHT_BASE.
> 
> Don't set a default for max_sectors at SCSI_DEFAULT_MAX_SECTORS, as
> scsi_host_alloc() will default to this value automatically.
> 
> Even though some drivers don't set proc_name, it won't make much difference
> to set as DRV_NAME.
> 
> Also add LIBSAS_SHT_BASE_NO_SLAVE_INIT for the hisi_sas drivers which have
> custom .slave_alloc and .slave_configure methods.

Looks like libata drivers have no problem overriding default values that were
set by __ATA_BASE_SHT. For example __ATA_BASE_SHT sets .can_queue .sdev_attrs
and then AHCI_SHT overrides those with AHCI specific values: 

#define AHCI_SHT(drv_name)                                              \       
        ATA_NCQ_SHT(drv_name),                                          \       
        .can_queue              = AHCI_MAX_CMDS,                        \       
        .sg_tablesize           = AHCI_MAX_SG,                          \       
        .dma_boundary           = AHCI_DMA_BOUNDARY,                    \       
        .shost_attrs            = ahci_shost_attrs,                     \       
        .sdev_attrs             = ahci_sdev_attrs 

Perhaps there is no need for LIBSAS_SHT_BASE_NO_SLAVE_INIT since hisi_sas
can use LIBSAS_SHT_BASE with .slave_alloc and .slave_configure overrides?

Similarly hisi_sas and pm8001 can override the default ".sg_tablesize = SG_ALL".

Thanks,
Igor

> 
> Reviewed-by: Jason Yan <yanaijie@huawei.com>
> Signed-off-by: John Garry <john.g.garry@oracle.com>
> ---
>  include/scsi/libsas.h | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
> index f5257103fdb6..de842602f47e 100644
> --- a/include/scsi/libsas.h
> +++ b/include/scsi/libsas.h
> @@ -726,4 +726,33 @@ void sas_notify_port_event(struct asd_sas_phy *phy, enum port_event event,
>  void sas_notify_phy_event(struct asd_sas_phy *phy, enum phy_event event,
>  			   gfp_t gfp_flags);
>  
> +#define __LIBSAS_SHT_BASE						\
> +	.module				= THIS_MODULE,			\
> +	.name				= DRV_NAME,			\
> +	.proc_name			= DRV_NAME,			\
> +	.queuecommand			= sas_queuecommand,		\
> +	.dma_need_drain			= ata_scsi_dma_need_drain,	\
> +	.target_alloc			= sas_target_alloc,		\
> +	.change_queue_depth		= sas_change_queue_depth,	\
> +	.bios_param			= sas_bios_param,		\
> +	.this_id			= -1,				\
> +	.eh_device_reset_handler	= sas_eh_device_reset_handler, 	\
> +	.eh_target_reset_handler	= sas_eh_target_reset_handler,	\
> +	.target_destroy			= sas_target_destroy,		\
> +	.ioctl				= sas_ioctl,			\
> +
> +#ifdef CONFIG_COMPAT
> +#define _LIBSAS_SHT_BASE		__LIBSAS_SHT_BASE		\
> +	.compat_ioctl			= sas_ioctl,
> +#else
> +#define _LIBSAS_SHT_BASE		__LIBSAS_SHT_BASE
> +#endif
> +
> +#define LIBSAS_SHT_BASE			_LIBSAS_SHT_BASE		\
> +	.slave_configure		= sas_slave_configure,		\
> +	.slave_alloc			= sas_slave_alloc,		\
> +
> +#define LIBSAS_SHT_BASE_NO_SLAVE_INIT	_LIBSAS_SHT_BASE
> +
> +
>  #endif /* _SASLIB_H_ */
> -- 
> 2.31.1
>