On 05/18/2010 08:13 AM, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
>
> This patch updates usr/bs_sg.c:bs_sg_cmd_submit() to process incoming scsi-generic IO
> of type SG_DXFER_TO_DEV and SG_DXFER_FROM_DEV using a single new struct scsi_cmnd->sg_iovec
> set using existing scsi_cmd.h scsi_get_[out,in]_[buffer,length]() macros.
>
> It also makes set_cmd_failed() properly return SAM_STAT_CHECK_CONDITION, which is expected
> by the bs_sg_cmd_submit() caller in usr/scsi.c:scsi_cmd_perform()
>
> Finally, this patch adds struct backingstore_template->bs_passthrough=1 that is used by
> bs_sg.c here and the next patch to hand off struct scsi_cmd for CDB passthrough.
>
> Signed-off-by: Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx>
> ---
> usr/bs_sg.c | 31 ++++++++++++++++++++++++-------
Why not add a new bs_bsg.c backing store that goes through BSG and not SG
and do it properly for all type of targets and commands?
Just a thought.
> usr/scsi_cmnd.h | 4 ++++
> usr/tgtd.h | 1 +
> 3 files changed, 29 insertions(+), 7 deletions(-)
>
> diff --git a/usr/bs_sg.c b/usr/bs_sg.c
> index 8baa480..9696392 100644
> --- a/usr/bs_sg.c
> +++ b/usr/bs_sg.c
> @@ -82,7 +82,7 @@ static int graceful_write(int fd, void *p_write, int to_write)
> return 0;
> }
>
> -static void set_cmd_failed(struct scsi_cmd *cmd)
> +static int set_cmd_failed(struct scsi_cmd *cmd)
> {
> int result = SAM_STAT_CHECK_CONDITION;
> uint16_t asc = ASC_READ_ERROR;
> @@ -90,11 +90,14 @@ static void set_cmd_failed(struct scsi_cmd *cmd)
>
> scsi_set_result(cmd, result);
> sense_data_build(cmd, key, asc);
> +
> + return result;
> }
>
> static int bs_sg_cmd_submit(struct scsi_cmd *cmd)
> {
> struct scsi_lu *dev = cmd->dev;
> + struct sg_iovec *iov = &cmd->sg_iovec;
> int fd = dev->fd;
> struct sg_io_hdr io_hdr;
> int err = 0;
> @@ -104,14 +107,27 @@ static int bs_sg_cmd_submit(struct scsi_cmd *cmd)
> io_hdr.cmd_len = cmd->scb_len;
> io_hdr.cmdp = cmd->scb;
>
> + if (scsi_get_data_dir(cmd) == DATA_BIDIRECTIONAL) {
Using bsg just really cleans this all function up.
IN_CMD => IN_HDR
OUT_CMD => OUT_HDR
no ifs and buts. The tgt's cmd looks like struct sg_io_v4 as if they
are twins ;-)
> + eprintf("Unable to process DATA_BIDIRECTIONAL to"
> + " SG_IO backstore\n");
> + return set_cmd_failed(cmd);
> + }
> +
> if (scsi_get_data_dir(cmd) == DATA_WRITE) {
> io_hdr.dxfer_direction = SG_DXFER_TO_DEV;
> - io_hdr.dxfer_len = scsi_get_out_length(cmd);
> - io_hdr.dxferp = (void *)scsi_get_out_buffer(cmd);
dxferp is already void* why do you need the cast?
> - } else {
> + io_hdr.dxfer_len = iov->iov_len = scsi_get_out_length(cmd);
> + iov->iov_base = (void *)scsi_get_out_buffer(cmd);
> + io_hdr.dxferp = &cmd->sg_iovec;
> + io_hdr.iovec_count = 1;
> + } else if (scsi_get_data_dir(cmd) == DATA_READ) {
> io_hdr.dxfer_direction = SG_DXFER_FROM_DEV;
> - io_hdr.dxfer_len = scsi_get_in_length(cmd);
> - io_hdr.dxferp = (void *)scsi_get_in_buffer(cmd);
> + io_hdr.dxfer_len = iov->iov_len = scsi_get_in_length(cmd);
> + iov->iov_base = (void *)scsi_get_in_buffer(cmd);
> + io_hdr.dxferp = &cmd->sg_iovec;
> + io_hdr.iovec_count = 1;
> + } else {
> + io_hdr.dxfer_direction = SG_DXFER_NONE;
> + io_hdr.dxfer_len = 0;
> }
> io_hdr.mx_sb_len = sizeof(cmd->sense_buffer);
> io_hdr.sbp = cmd->sense_buffer;
You might want to look into the new SG_FLAG_Q_AT_TAIL but this is available
only in new Kernels so it'll be a little hack
> @@ -125,7 +141,7 @@ static int bs_sg_cmd_submit(struct scsi_cmd *cmd)
> set_cmd_async(cmd);
> else {
> eprintf("failed to start cmd 0x%p\n", cmd);
> - set_cmd_failed(cmd);
> + return set_cmd_failed(cmd);
> }
> return 0;
> }
> @@ -238,6 +254,7 @@ static int bs_sg_cmd_done(struct scsi_cmd *cmd)
> static struct backingstore_template sg_bst = {
> .bs_name = "sg",
> .bs_datasize = 0,
> + .bs_passthrough = 1,
> .bs_open = bs_sg_open,
> .bs_close = bs_sg_close,
> .bs_cmd_submit = bs_sg_cmd_submit,
And again the Second patch should just fold into this one. And the final disposition will
just set the .bs_cmd_submit to the proper one.
[BTW if you want to keep struct backingstore_template sg_bst const (Which it is not, but
should be) then just have two of them and switch between them]
Boaz
> diff --git a/usr/scsi_cmnd.h b/usr/scsi_cmnd.h
> index 011f3e6..776ffb3 100644
> --- a/usr/scsi_cmnd.h
> +++ b/usr/scsi_cmnd.h
> @@ -17,6 +17,8 @@ struct scsi_data_buffer {
> uint64_t buffer;
> };
>
> +#include <scsi/sg.h>
> +
> struct scsi_cmd {
> struct target *c_target;
> /* linked it_nexus->cmd_hash_list */
> @@ -31,6 +33,8 @@ struct scsi_cmd {
> enum data_direction data_dir;
> struct scsi_data_buffer in_sdb;
> struct scsi_data_buffer out_sdb;
> + /* used for bs_sg.c:bs_sg_cmd_submit() */
> + struct sg_iovec sg_iovec;
>
> uint64_t cmd_itn_id;
> uint64_t offset;
> diff --git a/usr/tgtd.h b/usr/tgtd.h
> index 3323a9b..4f26a29 100644
> --- a/usr/tgtd.h
> +++ b/usr/tgtd.h
> @@ -117,6 +117,7 @@ struct device_type_template {
> struct backingstore_template {
> const char *bs_name;
> int bs_datasize;
> + int bs_passthrough;
> int (*bs_open)(struct scsi_lu *dev, char *path, int *fd, uint64_t *size);
> void (*bs_close)(struct scsi_lu *dev);
> int (*bs_init)(struct scsi_lu *dev);
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