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tcm_loop: kill tcm_loop_allocate_core_cmd
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This function makes little sense as a separate abstraction as it's deeply
interwinded with the control flow of its only caller.  Merged it into
tcm_loop_queuecommand after factoring out a helper to convert the task
attribute representation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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Christoph Hellwig authored and Nicholas Bellinger committed Feb 25, 2012
1 parent 59dcb5e commit f872c9f
Showing 1 changed file with 59 additions and 88 deletions.
147 changes: 59 additions & 88 deletions drivers/target/loopback/tcm_loop.c
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Original file line number Diff line number Diff line change
Expand Up @@ -48,81 +48,6 @@ static struct kmem_cache *tcm_loop_cmd_cache;

static int tcm_loop_hba_no_cnt;

/*
* Allocate a tcm_loop cmd descriptor from target_core_mod code
*
* Can be called from interrupt context in tcm_loop_queuecommand() below
*/
static struct se_cmd *tcm_loop_allocate_core_cmd(
struct tcm_loop_hba *tl_hba,
struct se_portal_group *se_tpg,
struct scsi_cmnd *sc)
{
struct se_cmd *se_cmd;
struct se_session *se_sess;
struct tcm_loop_nexus *tl_nexus = tl_hba->tl_nexus;
struct tcm_loop_cmd *tl_cmd;
int sam_task_attr;

if (!tl_nexus) {
scmd_printk(KERN_ERR, sc, "TCM_Loop I_T Nexus"
" does not exist\n");
set_host_byte(sc, DID_ERROR);
return NULL;
}
se_sess = tl_nexus->se_sess;

tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_ATOMIC);
if (!tl_cmd) {
pr_err("Unable to allocate struct tcm_loop_cmd\n");
set_host_byte(sc, DID_ERROR);
return NULL;
}
se_cmd = &tl_cmd->tl_se_cmd;
/*
* Save the pointer to struct scsi_cmnd *sc
*/
tl_cmd->sc = sc;
/*
* Locate the SAM Task Attr from struct scsi_cmnd *
*/
if (sc->device->tagged_supported) {
switch (sc->tag) {
case HEAD_OF_QUEUE_TAG:
sam_task_attr = MSG_HEAD_TAG;
break;
case ORDERED_QUEUE_TAG:
sam_task_attr = MSG_ORDERED_TAG;
break;
default:
sam_task_attr = MSG_SIMPLE_TAG;
break;
}
} else
sam_task_attr = MSG_SIMPLE_TAG;

/*
* Initialize struct se_cmd descriptor from target_core_mod infrastructure
*/
transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
scsi_bufflen(sc), sc->sc_data_direction, sam_task_attr,
&tl_cmd->tl_sense_buf[0]);

if (scsi_bidi_cmnd(sc))
se_cmd->se_cmd_flags |= SCF_BIDI;

/*
* Locate the struct se_lun pointer and attach it to struct se_cmd
*/
if (transport_lookup_cmd_lun(se_cmd, tl_cmd->sc->device->lun) < 0) {
kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
set_host_byte(sc, DID_NO_CONNECT);
return NULL;
}

return se_cmd;
}

/*
* Called by struct target_core_fabric_ops->new_cmd_map()
*
Expand Down Expand Up @@ -262,6 +187,25 @@ static int tcm_loop_change_queue_depth(
return sdev->queue_depth;
}

/*
* Locate the SAM Task Attr from struct scsi_cmnd *
*/
static int tcm_loop_sam_attr(struct scsi_cmnd *sc)
{
if (sc->device->tagged_supported) {
switch (sc->tag) {
case HEAD_OF_QUEUE_TAG:
return MSG_HEAD_TAG;
case ORDERED_QUEUE_TAG:
return MSG_ORDERED_TAG;
default:
break;
}
}

return MSG_SIMPLE_TAG;
}

/*
* Main entry point from struct scsi_host_template for incoming SCSI CDB+Data
* from Linux/SCSI subsystem for SCSI low level device drivers (LLDs)
Expand All @@ -274,6 +218,10 @@ static int tcm_loop_queuecommand(
struct se_portal_group *se_tpg;
struct tcm_loop_hba *tl_hba;
struct tcm_loop_tpg *tl_tpg;
struct se_session *se_sess;
struct tcm_loop_nexus *tl_nexus;
struct tcm_loop_cmd *tl_cmd;


pr_debug("tcm_loop_queuecommand() %d:%d:%d:%d got CDB: 0x%02x"
" scsi_buf_len: %u\n", sc->device->host->host_no,
Expand All @@ -290,24 +238,47 @@ static int tcm_loop_queuecommand(
*/
if (!tl_tpg->tl_hba) {
set_host_byte(sc, DID_NO_CONNECT);
sc->scsi_done(sc);
return 0;
goto out_done;
}
se_tpg = &tl_tpg->tl_se_tpg;
/*
* Determine the SAM Task Attribute and allocate tl_cmd and
* tl_cmd->tl_se_cmd from TCM infrastructure
*/
se_cmd = tcm_loop_allocate_core_cmd(tl_hba, se_tpg, sc);
if (!se_cmd) {
sc->scsi_done(sc);
return 0;

tl_nexus = tl_hba->tl_nexus;
if (!tl_nexus) {
scmd_printk(KERN_ERR, sc, "TCM_Loop I_T Nexus"
" does not exist\n");
set_host_byte(sc, DID_ERROR);
goto out_done;
}
/*
* Queue up the newly allocated to be processed in TCM thread context.
*/
se_sess = tl_nexus->se_sess;

tl_cmd = kmem_cache_zalloc(tcm_loop_cmd_cache, GFP_ATOMIC);
if (!tl_cmd) {
pr_err("Unable to allocate struct tcm_loop_cmd\n");
set_host_byte(sc, DID_ERROR);
goto out_done;
}
se_cmd = &tl_cmd->tl_se_cmd;
tl_cmd->sc = sc;

transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
scsi_bufflen(sc), sc->sc_data_direction,
tcm_loop_sam_attr(sc), &tl_cmd->tl_sense_buf[0]);

if (scsi_bidi_cmnd(sc))
se_cmd->se_cmd_flags |= SCF_BIDI;

if (transport_lookup_cmd_lun(se_cmd, tl_cmd->sc->device->lun) < 0) {
kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
set_host_byte(sc, DID_NO_CONNECT);
goto out_done;
}

transport_generic_handle_cdb_map(se_cmd);
return 0;

out_done:
sc->scsi_done(sc);
return 0;
}

/*
Expand Down

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