scsi_debug: virtual_gb ignores sector_size

In the scsi_debug driver, the virtual_gb option ignores the sector_size, implicitly assuming that is 512 bytes.
So if 'virtual_gb=1 sector_size=4096' the result is an 8 GB (virtual) disk.

ChangeLog:
- correct get_sdebug_capacity() calculation of sectors when virtual_gb option is used. Needs to take into account sector_size.

@@ -58,7 +58,7 @@
 #include "scsi_logging.h"
 
 #define SCSI_DEBUG_VERSION "1.82"
-static const char * scsi_debug_version_date = "20100324";
+static const char * scsi_debug_version_date = "20100425";
 
 /* Additional Sense Code (ASC) */
 #define NO_ADDITIONAL_SENSE 0x0

@@ -961,7 +961,8 @@ static int resp_start_stop(struct scsi_c
 static sector_t get_sdebug_capacity(void)
 {
 	if (scsi_debug_virtual_gb > 0)
-		return 2048 * 1024 * (sector_t)scsi_debug_virtual_gb;
+		return (sector_t)scsi_debug_virtual_gb *
+			(1073741824 / scsi_debug_sector_size);
 	else
 		return sdebug_store_sectors;
 }

Doug> In the scsi_debug driver, the virtual_gb option ignores the Doug> sector_size, implicitly assuming that is 512 bytes. So if Doug> 'virtual_gb=1 sector_size=4096' the result is an 8 GB (virtual) Doug> disk.

James: We've got quite a few unmerged scsi_debug changes out there right now. Are you keeping track??

Martin K. Petersen	Oracle Linux Engineering

Yes, but unless I missed something, Doug is still the maintainer, so I'm waiting for his testing and ack on some of the ones you submitted.

James