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

[Cédric Le Goater]

On 4/3/20 1:19 AM, Matthew R. Ochs wrote:
> 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.

I like ENXIO for XIVE matters. 

C. 

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