Re: [PATCH 08/10] am53c974: BLAST residual handling

[Hannes Reinecke <hare@suse.de>]

On 11/21/2014 11:10 AM, Paolo Bonzini wrote:
> 
> 
> On 21/11/2014 10:27, Hannes Reinecke wrote:
>> The am53c974 has an design issue where a single byte might be
>> left in the SCSI FIFO after a DMA transfer.
>> As the handling code is currently untested add a WARN_ON()
>> statement here.
>>
>> Signed-off-by: Hannes Reinecke <hare@suse.de>
>> ---
>>  drivers/scsi/am53c974.c |  6 ++++++
>>  drivers/scsi/esp_scsi.c | 29 +++++++++++++++++++++++++++++
>>  drivers/scsi/esp_scsi.h |  1 +
>>  3 files changed, 36 insertions(+)
>>
>> diff --git a/drivers/scsi/am53c974.c b/drivers/scsi/am53c974.c
>> index 652762e..0b7643e 100644
>> --- a/drivers/scsi/am53c974.c
>> +++ b/drivers/scsi/am53c974.c
>> @@ -195,6 +195,12 @@ static void pci_esp_dma_drain(struct esp *esp)
>>  	shost_printk(KERN_INFO, esp->host,
>>  		     "DMA blast done (%d tries, %d bytes left)\n", lim, resid);
>>  #endif
>> +	/* BLAST residual handling is currently untested */
>> +	if (WARN_ON(resid == 1)) {
> 
> WARN_ON_ONCE?
> 
I have not seen it once so far, so I doubt it's a common
case. But yeah, WARN_ON_ONCE is probably better.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 21284 (AG Nürnberg)
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