On Mon, 2010-06-07 at 11:40 +0300, Boaz Harrosh wrote:
> On 06/07/2010 06:50 AM, Nicholas A. Bellinger wrote:
> > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
> >
> > This patch adds initial support for the block layer implementation of the sg v4 interface
> > (BSG) -> STGT with a new struct backingstore_template bsg_bst sharing code with the
> > original sg_bst. It adds for new function bs_bsg_cmd_submit() for incoming write I/O
> > and bs_bsg_cmd_complete() for polling read I/O using include/linux/bsg.h:struct sg_io_v4.
> >
> > This patch also splits up bs_sg_open() to support both BSG and SG looking for the
> > path "/dev/bsg" in bs_sg_open(), and getting max_queue using SG_GET_COMMAND_Q and
> > calling SG_SET_RESERVED_SIZE (following the original bs_sg code in init_sg_device)
> >
> > Also chk_bsg_device() currently using a hardcoded 254 major as def for BSG does not
> > appear in include/linux/major.h just yet..
> >
> > So far this has been tested with STGT/iSCSI <-> BSG <-> TCM_Loop SPC-4 iSCSI Target
> > Port emulation and is able to mkfs, fsck and mount a filesystem from a TCM/IBLOCK
> > Linux LVM kernel level backstore
> >
> > Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
> > ---
> > usr/bs_sg.c | 178 +++++++++++++++++++++++++++++++++++++++++++++++++++---
> > usr/scsi_cmnd.h | 7 ++
> > 2 files changed, 175 insertions(+), 10 deletions(-)
> >
> > diff --git a/usr/bs_sg.c b/usr/bs_sg.c
> > index 23676ef..d071714 100644
> > --- a/usr/bs_sg.c
> > +++ b/usr/bs_sg.c
<SNIP>
> > +
> > +static int bs_bsg_cmd_submit(struct scsi_cmd *cmd)
> > +{
> > + struct scsi_lu *dev = cmd->dev;
> > + int fd = dev->fd;
> > + struct sg_io_v4 *io_hdr = &cmd->cmd_bsg_hdr;
> > + int err = 0;
> > + /*
> > + * Following linux/include/linux/bsg.h
> > + */
> > + /* [i] 'Q' to differentiate from v3 */
> > + io_hdr->guard = 'Q';
> > + io_hdr->protocol = BSG_PROTOCOL_SCSI;
> > + io_hdr->subprotocol = BSG_SUB_PROTOCOL_SCSI_CMD;
> > + io_hdr->request_len = cmd->scb_len;
> > + io_hdr->request = (unsigned long )cmd->scb;
> > +
> > + if (scsi_get_data_dir(cmd) == DATA_WRITE) {
>
> Why the if? both sides are fully bidi just remove the ifs
> and: OUT <= OUT, IN <= IN
>
Whoops, thanks for pointing this one out (again). Tested with
unidirection commands and included into my local tgt.git/pass that I
will send along to Tomo-san..
Btw, I still need to sort out BIDI support for TCM_Loop at some point in
the not too distant future. What would be a good way to generate BIDI
traffic into STGT or a local SCSI LLD..?
Best,
--nab
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