On 02/12/2018 06:39 AM, Shivasharan S wrote:
> Problem Statement:
> Sending I/O through 32 bit descriptors to Ventura series of controller
> results in IO timeout on certain conditions.
>  
> This error only occurs on systems with high I/O activity on
> Ventura series controllers.
>   
> Changes in this patch will prevent driver from using 32 bit descriptor
> and use 64 bit Descriptors.
>
> Cc: <sta...@vger.kernel.org>
> Signed-off-by: Kashyap Desai <kashyap.de...@broadcom.com>
> Signed-off-by: Shivasharan S <shivasharan.srikanteshw...@broadcom.com>
> ---
>  drivers/scsi/megaraid/megaraid_sas_fusion.c | 37 
> ++++++++++-------------------
>  1 file changed, 12 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c 
> b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> index 073ced07e662..09f2bdb14b0a 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> @@ -226,26 +226,21 @@ static void
>  megasas_fire_cmd_fusion(struct megasas_instance *instance,
>               union MEGASAS_REQUEST_DESCRIPTOR_UNION *req_desc)
>  {
> -     if (instance->adapter_type == VENTURA_SERIES)
> -             writel(le32_to_cpu(req_desc->u.low),
> -                     &instance->reg_set->inbound_single_queue_port);
> -     else {
>  #if defined(writeq) && defined(CONFIG_64BIT)
> -             u64 req_data = (((u64)le32_to_cpu(req_desc->u.high) << 32) |
> -                             le32_to_cpu(req_desc->u.low));
> +     u64 req_data = (((u64)le32_to_cpu(req_desc->u.high) << 32) |
> +             le32_to_cpu(req_desc->u.low));
>  
> -             writeq(req_data, &instance->reg_set->inbound_low_queue_port);
> +     writeq(req_data, &instance->reg_set->inbound_low_queue_port);
>  #else
> -             unsigned long flags;
> -             spin_lock_irqsave(&instance->hba_lock, flags);
> -             writel(le32_to_cpu(req_desc->u.low),
> -                     &instance->reg_set->inbound_low_queue_port);
> -             writel(le32_to_cpu(req_desc->u.high),
> -                     &instance->reg_set->inbound_high_queue_port);
> -             mmiowb();
> -             spin_unlock_irqrestore(&instance->hba_lock, flags);
> +     unsigned long flags;
> +     spin_lock_irqsave(&instance->hba_lock, flags);
> +     writel(le32_to_cpu(req_desc->u.low),
> +             &instance->reg_set->inbound_low_queue_port);
> +     writel(le32_to_cpu(req_desc->u.high),
> +             &instance->reg_set->inbound_high_queue_port);
> +     mmiowb();
> +     spin_unlock_irqrestore(&instance->hba_lock, flags);
>  #endif
> -     }
>  }
>  
>  /**
> @@ -982,7 +977,6 @@ megasas_ioc_init_fusion(struct megasas_instance *instance)
>       const char *sys_info;
>       MFI_CAPABILITIES *drv_ops;
>       u32 scratch_pad_2;
> -     unsigned long flags;
>       ktime_t time;
>       bool cur_fw_64bit_dma_capable;
>  
> @@ -1121,14 +1115,7 @@ megasas_ioc_init_fusion(struct megasas_instance 
> *instance)
>                       break;
>       }
>  
> -     /* For Ventura also IOC INIT required 64 bit Descriptor write. */
> -     spin_lock_irqsave(&instance->hba_lock, flags);
> -     writel(le32_to_cpu(req_desc.u.low),
> -            &instance->reg_set->inbound_low_queue_port);
> -     writel(le32_to_cpu(req_desc.u.high),
> -            &instance->reg_set->inbound_high_queue_port);
> -     mmiowb();
> -     spin_unlock_irqrestore(&instance->hba_lock, flags);
> +     megasas_fire_cmd_fusion(instance, &req_desc);
>  
>       wait_and_poll(instance, cmd, MFI_POLL_TIMEOUT_SECS);
>  

Reviewed-by: Tomas Henzl <the...@redhat.com>

Please also remove the text
 * Ventura supports 32 bit Descriptor.
 * Prior to Ventura (12G) MR controller supports 64 bit Descriptor.
from the function description (not urgent may happen later)

Thanks,
Tomas


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