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From: Nicholas A. Bellinger on 7 Jun 2010 00:00
From: Nicholas Bellinger <nab(a)linux-iscsi.org>

This patch adds struct device_type_template sg_template to usr/bs_sg.c used for STGT LUN
passthrough with the new bs_sg_lu_init() and bs_sg_rw() functions following usr/sbc.c code
for TYPE_DISK, but should work for any device type.

It also adds struct bs_sg_init() that is called from existing usr/target.c:tgt_device_create()
code via struct backingstore_template->bs_init() in order to setup the passthrough specific
queue and completion handlers for struct scsi_lu->cmd_perform() and ->cmd_done().

Signed-off-by: Nicholas A. Bellinger <nab(a)linux-iscsi.org>
---
usr/bs_sg.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 69 insertions(+), 0 deletions(-)

diff --git a/usr/bs_sg.c b/usr/bs_sg.c
index 8baa480..23676ef 100644
--- a/usr/bs_sg.c
+++ b/usr/bs_sg.c
@@ -38,9 +38,12 @@
#include "util.h"
#include "tgtd.h"
#include "scsi.h"
+#include "spc.h"
+#include "tgtadm_error.h"

#define BS_SG_RESVD_SZ (512 * 1024)
#define BS_SG_TIMEOUT 2000
+#define BS_SG_SHIFT 9

static int graceful_read(int fd, void *p_read, int to_read)
{
@@ -82,6 +85,32 @@ static int graceful_write(int fd, void *p_write, int to_write)
return 0;
}

+static int bs_sg_rw(int host_no, struct scsi_cmd *cmd)
+{
+ int ret;
+ unsigned char key = ILLEGAL_REQUEST;
+ uint16_t asc = ASC_LUN_NOT_SUPPORTED;
+
+ cmd->scsi_cmd_done = target_cmd_io_done;
+
+ cmd->offset = (scsi_rw_offset(cmd->scb) << BS_SG_SHIFT);
+ ret = cmd->dev->bst->bs_cmd_submit(cmd);
+ if (ret) {
+ key = HARDWARE_ERROR;
+ asc = ASC_INTERNAL_TGT_FAILURE;
+ } else {
+ set_cmd_mmapio(cmd);
+ return SAM_STAT_GOOD;
+ }
+
+ cmd->offset = 0;
+ scsi_set_in_resid_by_actual(cmd, 0);
+ scsi_set_out_resid_by_actual(cmd, 0);
+
+ sense_data_build(cmd, key, asc);
+ return SAM_STAT_CHECK_CONDITION;
+}
+
static void set_cmd_failed(struct scsi_cmd *cmd)
{
int result = SAM_STAT_CHECK_CONDITION;
@@ -192,6 +221,25 @@ static int init_sg_device(int fd)
return 0;
}

+static int bs_sg_init(struct scsi_lu *lu)
+{
+ /*
+ * Setup struct scsi_lu->cmd_perform() passthrough pointer
+ * (if available) for the underlying device type.
+ */
+ lu->cmd_perform = &target_cmd_perform_passthrough;
+ if (!(lu->cmd_perform)) {
+ eprintf("Unable to locate lu->cmd_perform() for bs_sg\n");
+ return -1;
+ }
+ /*
+ * Setup struct scsi_lu->cmd_done() passthrough pointer using
+ * usr/target.c:__cmd_done_passthrough().
+ */
+ lu->cmd_done = &__cmd_done_passthrough;
+ return 0;
+}
+
static int bs_sg_open(struct scsi_lu *lu, char *path, int *fd, uint64_t *size)
{
int sg_fd, err;
@@ -235,16 +283,37 @@ static int bs_sg_cmd_done(struct scsi_cmd *cmd)
return 0;
}

+static int bs_sg_lu_init(struct scsi_lu *lu)
+{
+ if (spc_lu_init(lu))
+ return TGTADM_NOMEM;
+
+ return 0;
+}
+
static struct backingstore_template sg_bst = {
.bs_name = "sg",
.bs_datasize = 0,
+ .bs_passthrough = 1,
+ .bs_init = bs_sg_init,
.bs_open = bs_sg_open,
.bs_close = bs_sg_close,
.bs_cmd_submit = bs_sg_cmd_submit,
.bs_cmd_done = bs_sg_cmd_done,
};

+static struct device_type_template sg_template = {
+ .type = 0,
+ .lu_init = bs_sg_lu_init,
+ .lu_config = spc_lu_config,
+ .lu_online = spc_lu_online,
+ .lu_offline = spc_lu_offline,
+ .lu_exit = spc_lu_exit,
+ .cmd_passthrough = bs_sg_rw,
+};
+
__attribute__((constructor)) static void bs_sg_constructor(void)
{
register_backingstore_template(&sg_bst);
+ device_type_register(&sg_template);
}
--
1.5.6.5

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Prev: [PATCH 3/3] [tgt]: Add BSG v4 backstore support to usr/bs_sg.c
Next: linux-next: build failure after merge of the final tree (tile tree related)