spi_dv_device_compare_inquiry() oddity

[Hannes Reinecke <hare@suse.de>]

Hi all,

trying to get my CD-ROM to behave I stumbled across the following:

drivers/scsi/scsi_transport_spi.c:spi_dv_device_compare_inquiry()

spi_dv_device_compare_inquiry(struct scsi_device *sdev, u8 *buffer,
			      u8 *ptr, const int retries)
{
	int r, result;
	const int len = sdev->inquiry_len;
	const char spi_inquiry[] = {
		INQUIRY, 0, 0, 0, len, 0
	};

	for (r = 0; r < retries; r++) {
		memset(ptr, 0, len);

		result = spi_execute(sdev, spi_inquiry, DMA_FROM_DEVICE,
				     ptr, len, NULL);
		
		if(result || !scsi_device_online(sdev)) {
			scsi_device_set_state(sdev, SDEV_QUIESCE);
			return SPI_COMPARE_FAILURE;
		}

		/* If we don't have the inquiry data already, the
		 * first read gets it */
		if (ptr == buffer) {
			ptr += len;
			--r;
			continue;
		}

		if (memcmp(buffer, ptr, len) != 0)
			/* failure */
			return SPI_COMPARE_FAILURE;
	}
	return SPI_COMPARE_SUCCESS;
}

So if the inquiry succeeds we have to retry to check that the inquiry
_really_ succeded? Am I missing some subleties here?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke			hare@suse.de
SuSE Linux Products GmbH		S390 & zSeries
Maxfeldstraße 5				+49 911 74053 688
90409 Nürnberg				http://www.suse.de

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