[PATCH 1/4] scsi: cxlflash: Access interrupt trigger page from xive directly

[Matthew R. Ochs]

On Thu, Apr 02, 2020 at 05:43:49PM +0200, Frederic Barrat wrote:
> xive is already mapping the trigger page in kernel space and it can be
> accessed through standard APIs, so let's reuse it and simplify the code.
> 
> Signed-off-by: Frederic Barrat <fbarrat at linux.ibm.com>
> ---
>  drivers/scsi/cxlflash/ocxl_hw.c | 17 +++++++----------
>  drivers/scsi/cxlflash/ocxl_hw.h |  1 -
>  2 files changed, 7 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/scsi/cxlflash/ocxl_hw.c b/drivers/scsi/cxlflash/ocxl_hw.c
> index 7018cd802569..59452850f71c 100644
> --- a/drivers/scsi/cxlflash/ocxl_hw.c
> +++ b/drivers/scsi/cxlflash/ocxl_hw.c
> @@ -15,7 +15,8 @@
>  #include <linux/pseudo_fs.h>
>  #include <linux/poll.h>
>  #include <linux/sched/signal.h>
> -
> +#include <linux/interrupt.h>
> +#include <asm/xive.h>
>  #include <misc/ocxl.h>
>  
>  #include <uapi/misc/cxl.h>
> @@ -180,7 +181,7 @@ static int afu_map_irq(u64 flags, struct ocxlflash_context *ctx, int num,
>  	struct ocxl_hw_afu *afu = ctx->hw_afu;
>  	struct device *dev = afu->dev;
>  	struct ocxlflash_irqs *irq;
> -	void __iomem *vtrig;
> +	struct xive_irq_data *xd;
>  	u32 virq;
>  	int rc = 0;
>  
> @@ -204,15 +205,14 @@ static int afu_map_irq(u64 flags, struct ocxlflash_context *ctx, int num,
>  		goto err1;
>  	}
>  
> -	vtrig = ioremap(irq->ptrig, PAGE_SIZE);
> -	if (unlikely(!vtrig)) {
> -		dev_err(dev, "%s: Trigger page mapping failed\n", __func__);
> -		rc = -ENOMEM;
> +	xd = irq_get_handler_data(virq);
> +	if (unlikely(!xd)) {
> +		dev_err(dev, "%s: Can't get interrupt data\n", __func__);

The removal of setting the return code injects a bug should this error leg
ever be encountered. So we should either keep the rc statement e.g. -EINVAL,
-ENXIO, -ENODEV, etc., or remove this error leg. I lean towards keeping the
statement.

>  		goto err2;
>  	}
>  
>  	irq->virq = virq;
> -	irq->vtrig = vtrig;
> +	irq->vtrig = xd->trig_mmio;
>  out:
>