Re: [clk:hb_3.5 11/12] drivers/ata/ahci_platform.c:129:2: warning: initialization discards 'const' q

Rob Herring
2012-07-09T02:44:24Z

On 07/08/2012 09:08 PM, Fengguang Wu wrote:
> On Mon, Jul 09, 2012 at 01:17:51AM +0800, wfg@linux.intel.com wrote:
>> Hi Rob,
>>
>> There are new compile warnings show up in
>>
>> tree: git://sources.calxeda.com/kernel/linux.git hb_3.5
>> head: 67e0749b2f1c5908346485f5cb54af9f3a01e047
>> commit: df55ea8b7785fb704475ad562d445ac402719dc0 [11/12] ahci_platform: add custom hard reset for Calxeda ahci ctrlr
>>
>> All warnings:
>>
>> drivers/ata/ahci_platform.c:125:9: sparse: Initializer entry defined twice
>> drivers/ata/ahci_platform.c:125:9: also defined here
>
> That warning is due to
>
> #define AHCI_SHT(drv_name) \
> ATA_NCQ_SHT(drv_name), \
> => .can_queue = AHCI_MAX_CMDS - 1, \
> .sg_tablesize = AHCI_MAX_SG, \
> .dma_boundary = AHCI_DMA_BOUNDARY, \
> .shost_attrs = ahci_shost_attrs, \
> => .sdev_attrs = ahci_sdev_attrs
>
> Re initilizes .can_queue and sdev_attrs to different values that was initially
> defined in
>
> #define ATA_BASE_SHT(drv_name) \
> .module = THIS_MODULE, \
> .name = drv_name, \
> .ioctl = ata_scsi_ioctl, \
> .queuecommand = ata_scsi_queuecmd, \
> => .can_queue = ATA_DEF_QUEUE, \
> .this_id = ATA_SHT_THIS_ID, \
> .cmd_per_lun = ATA_SHT_CMD_PER_LUN, \
> .emulated = ATA_SHT_EMULATED, \
> .use_clustering = ATA_SHT_USE_CLUSTERING, \
> .proc_name = drv_name, \
> .slave_configure = ata_scsi_slave_config, \
> .slave_destroy = ata_scsi_slave_destroy, \
> .bios_param = ata_std_bios_param, \
> .unlock_native_capacity = ata_scsi_unlock_native_capacity, \
> => .sdev_attrs = ata_common_sdev_attrs
>
> #define ATA_NCQ_SHT(drv_name) \
> ATA_BASE_SHT(drv_name), \
> .change_queue_depth = ata_scsi_change_queue_depth
>
> Perhaps not easily fixable..
>
>> drivers/ata/ahci_platform.c:129:67: sparse: incorrect type in initializer (different modifiers)
>> drivers/ata/ahci_platform.c:129:67: expected void *data
>> drivers/ata/ahci_platform.c:129:67: got struct ata_port_info static const [toplevel] *
>> drivers/ata/ahci_platform.c:129:2: warning: initialization discards 'const' qualifier from pointer target type [enabled by default]
>
> Rob,
>
> Please consider folding this trivial fix for that warning.
>
> diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
> index 9a155ba..a7fcd0a 100644
> --- a/drivers/ata/ahci_platform.c
> +++ b/drivers/ata/ahci_platform.c
> @@ -126,7 +126,7 @@ static struct scsi_host_template ahci_platform_sht = {
> };
>
> static const struct of_device_id ahci_of_match[] = {
> - { .compatible = "calxeda,hb-ahci", .data = &ahci_port_info[CALXEDA_AHCI], },
> + { .compatible = "calxeda,hb-ahci", .data = (void *)&ahci_port_info[CALXEDA_AHCI], },

I believe the warning is about const. Casting away the const is not the
right solution. There is a patch in flight to constify
of_device_id.data, but that has it's own challenges.

Rob

> {},
> };
> MODULE_DEVICE_TABLE(of, ahci_of_match);
>