On Tue, 2010-05-18 at 13:39 +0900, FUJITA Tomonori wrote: > On Mon, 17 May 2010 22:12:54 -0700 > "Nicholas A. Bellinger" <nab@xxxxxxxxxxxxxxx> wrote: > > > These are two patches to allow the STGT SG_IO backstore to function using a > > new struct scsi_cmd->sg_iovec member with sg_io_hdr->iovec_count=1, and to update > > usr/scsi.c:scsi_cmd_perform() to allow for a hand off incoming descriptors into the > > struct device_type_template->cmd_passthrough() function pointer. > > > > I initially updated usr/sbc.c to set sbc_rw() as it's CDB passthrough function for > > TYPE_DISK, but the logic should apply to any device types *_rw() functions. Please let > > me know if this makes sense, and I will look at updating the other stgt device types. > > > > So far with this patch, I am able to successfully mkfs new iSCSI TYPE_DISK LUNS with > > Open-iSCSI to the userspace STGT iSCSI fabric module + SG_IO into kernel level TCM_Loop > > virtual iSCSI target ports on a x86 HVM, and bulk 512KB DATA_SG_IO payloads between STGT > > and TCM_Loop are now functioning as expected. > > > > There is one unresolved issue that I ran into while running initially with TCM_Loop > > and struct scsi_device->max_sectors=256. SG_IO writes larger than the > > struct scsi_device->max_sectors are being returned with -EINVAL, but it appears that > > the CHECK_CONDITION is not actually being propigated back into STGT/iSCSI. > > > > After increasing the TCM_Loop ports to struct scsi_device->max_sectors=1024 following > > the Open-iSCSI Initiator default, the 512KB paylods begin work as expected. I will need > > to have a look at the case for CDB length > max_sectors, which means that bs_sg.c getting > > the correct scsi_status and sense data out of the kernel might still need more work. > > > > In the mean time, please have a look at applying these patches. > > > > Best, > > > > Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx> > > > > Nicholas Bellinger (2): > > [tgt]: Add proper CDB passthrough for SG_IO backstores > > [tgt]: Add support for SG_IO CDB passthrough in scsi_cmd_perform() > > > > usr/bs_sg.c | 31 ++++++++++++++++++++++++------- > > usr/sbc.c | 1 + > > usr/scsi.c | 11 +++++++++++ > > usr/scsi_cmnd.h | 4 ++++ > > usr/tgtd.h | 2 ++ > > 5 files changed, 42 insertions(+), 7 deletions(-) > > Thanks! Surely, the first patch looks fine. > Great! Please let me know if I should also generate patches for conversion of remaining STGT struct device_type_templates for proper SG_IO passthrough support. > I thought that you want to send all SCSI commands to your in-kernel > target code via SG_IO. That's, you want the proper 'pass-through' code > since tgt's pass-through code is broken. > > However, looks like non I/O commands are still performed in user-space > tgt code and only I/O commands goes to kernel via SG_IO. Hmm, that's > what you want to do? Hmmm, not sure what you mean here.. AFAICT using the newly provided struct device_type_template->cmd_passthrough() instead CDB emulation specific callers in usr/scsi.c:scsi_cmd_perform() with device type template cmd->dev->dev_type_template.ops[op].cmd_perform(() will always capture incoming struct scsi_cmnd for SG_IO passthrough before the device type CDB userspace STGT emulation execution and hand off into .cmd_perform()..? This is why the patches to use sbc_rw() as device type passthrough works for TYPE_DISK into SG_IO backstores with [READ,WRITE]_[6,10,12,16]) CDBs, yes? Best, --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
