On Sun, 2012-10-07 at 09:16 +0100, James Bottomley wrote: > On Sat, 2012-10-06 at 23:11 -0700, Nicholas A. Bellinger wrote: > > On Sat, 2012-10-06 at 21:49 -0400, Christoph Hellwig wrote: > > > Currenly all non-pscsi bakcneds report their standards version as > > > SPC 2 via ->get_device_rev. > > > > No, the proper on-the-wire bits to signal SPC-3 compliance are already > > being returned by virtual backend drivers within standard INQUIRY > > payload data. > > > > Notice the comment: > > > > root@tifa:/usr/src/target-pending.git# grep SCSI_SPC_2 drivers/target/*.c > > drivers/target/target_core_file.c: return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */ > > drivers/target/target_core_iblock.c: return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */ > > drivers/target/target_core_rd.c: return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */ > > That's causing confusion, I think! > > > > In addition to putting it into the > > > inquirty data in spc_emulate_inquiry_std we also use it in two > > > places to check on the version of the persistent reservation and > > > alua support. What is the benefit of supporting the old-style SCSI 2 > > > reservations and ALUA support when they can't be used at all with > > > the virtual backends, and can only be used in the corner case emulated > > > ALUA/PR support for pscsi? > > > > > > > It's the include/scsi/scsi.h SCSI_3 + SCSI_SPC_* version definition > > names that are incorrect: > > > > #define SCSI_UNKNOWN 0 > > #define SCSI_1 1 > > #define SCSI_1_CCS 2 > > #define SCSI_2 3 > > #define SCSI_3 4 /* SPC */ > > #define SCSI_SPC_2 5 > > #define SCSI_SPC_3 6 > > > > from spc4r30 section 6.4.2 Standard INQUIRY data, Table 142 -- Version: > > > > 00h The device server does not claim conformance to any standard. > > 01h to 02h Obsolete > > 03h The device server complies to ANSI INCITS 301-1997 (a withdrawn standard). > > 04h The device server complies to ANSI INCITS 351-2001 (SPC-2). > > 05h The device server complies to ANSI INCITS 408-2005 (SPC-3). > > 06h The device server complies to this standard. > > > > How about the following patch to fix the long-standing incorrect name > > usage of these three scsi.h defines..? > > Because it's not incorrect. Your confusion is that the SCSI_ constants > should match the inquiry data ... they shouldn't. No, my current confusion is stemming from why it's OK for SCSI_SPC_[2,3] constant names+values to not match what is actually defined in SPC-4 drafts for what target INQUIRY emulation bits end up going 'over the wire'. > Look where we set > scsi_level in scsi_scan.c:708-713. We have to fit an extra identifier > for SCSI_1_CCS so the scsi_level doesn't actually match the inquiry > data; it's incremented by 1 for SCSI_3 and above. The extra increment by 1 is required by some Linux/SCSI client implementation dependent requirements, yes..? > SCSI_3 does exist, by > the way, it was defined in the first version of SPC and there are some > devices which conform to it. > Regardless, SCSI_SPC_[2,3] -> SCSI_SPC[3,4] constants for target-core + scsi-core should still be re-named to avoid the extra confusion this introduces for folks reading code. --nab -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
