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authorChristoph Hellwig <hch@infradead.org>2012-02-02 17:04:41 -0500
committerNicholas Bellinger <nab@linux-iscsi.org>2012-02-25 14:37:48 -0800
commitafe2cb7fb111ac52ec95ab2bfb19d9d9e0d52ed8 (patch)
treef4ae15c8e06727b90e81405776d32d59c71aafcc /drivers/target/loopback
parentf872c9f417a38a08b6ffe46e1f937d3db1d22775 (diff)
downloadvexpress-lsk-afe2cb7fb111ac52ec95ab2bfb19d9d9e0d52ed8.tar.gz
tcm_loop: defer all command submissions to workqueue
Apply the qla2xxx model of submitting all commands from a workqueue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/loopback')
-rw-r--r--drivers/target/loopback/tcm_loop.c97
-rw-r--r--drivers/target/loopback/tcm_loop.h2
2 files changed, 58 insertions, 41 deletions
diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index b1edc517f4e..cb8893f303a 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -44,6 +44,7 @@
/* Local pointer to allocated TCM configfs fabric module */
static struct target_fabric_configfs *tcm_loop_fabric_configfs;
+static struct workqueue_struct *tcm_loop_workqueue;
static struct kmem_cache *tcm_loop_cmd_cache;
static int tcm_loop_hba_no_cnt;
@@ -206,32 +207,19 @@ static int tcm_loop_sam_attr(struct scsi_cmnd *sc)
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)
- */
-static int tcm_loop_queuecommand(
- struct Scsi_Host *sh,
- struct scsi_cmnd *sc)
+static void tcm_loop_submission_work(struct work_struct *work)
{
- struct se_cmd *se_cmd;
- struct se_portal_group *se_tpg;
+ struct tcm_loop_cmd *tl_cmd =
+ container_of(work, struct tcm_loop_cmd, work);
+ struct se_cmd *se_cmd = &tl_cmd->tl_se_cmd;
+ struct scsi_cmnd *sc = tl_cmd->sc;
+ struct tcm_loop_nexus *tl_nexus;
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,
- sc->device->id, sc->device->channel, sc->device->lun,
- sc->cmnd[0], scsi_bufflen(sc));
- /*
- * Locate the tcm_loop_hba_t pointer
- */
tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
+
/*
* Ensure that this tl_tpg reference from the incoming sc->device->id
* has already been configured via tcm_loop_make_naa_tpg().
@@ -240,7 +228,6 @@ static int tcm_loop_queuecommand(
set_host_byte(sc, DID_NO_CONNECT);
goto out_done;
}
- se_tpg = &tl_tpg->tl_se_tpg;
tl_nexus = tl_hba->tl_nexus;
if (!tl_nexus) {
@@ -249,18 +236,9 @@ static int tcm_loop_queuecommand(
set_host_byte(sc, DID_ERROR);
goto out_done;
}
- 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,
+ transport_init_se_cmd(se_cmd, tl_tpg->tl_se_tpg.se_tpg_tfo,
+ tl_nexus->se_sess,
scsi_bufflen(sc), sc->sc_data_direction,
tcm_loop_sam_attr(sc), &tl_cmd->tl_sense_buf[0]);
@@ -274,10 +252,37 @@ static int tcm_loop_queuecommand(
}
transport_generic_handle_cdb_map(se_cmd);
- return 0;
+ return;
out_done:
sc->scsi_done(sc);
+ return;
+}
+
+/*
+ * ->queuecommand can be and usually is called from interrupt context, so
+ * defer the actual submission to a workqueue.
+ */
+static int tcm_loop_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
+{
+ 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,
+ sc->device->id, sc->device->channel, sc->device->lun,
+ sc->cmnd[0], scsi_bufflen(sc));
+
+ 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);
+ sc->scsi_done(sc);
+ return 0;
+ }
+
+ tl_cmd->sc = sc;
+ INIT_WORK(&tl_cmd->work, tcm_loop_submission_work);
+ queue_work(tcm_loop_workqueue, &tl_cmd->work);
return 0;
}
@@ -1458,7 +1463,11 @@ static void tcm_loop_deregister_configfs(void)
static int __init tcm_loop_fabric_init(void)
{
- int ret;
+ int ret = -ENOMEM;
+
+ tcm_loop_workqueue = alloc_workqueue("tcm_loop", 0, 0);
+ if (!tcm_loop_workqueue)
+ goto out;
tcm_loop_cmd_cache = kmem_cache_create("tcm_loop_cmd_cache",
sizeof(struct tcm_loop_cmd),
@@ -1467,20 +1476,27 @@ static int __init tcm_loop_fabric_init(void)
if (!tcm_loop_cmd_cache) {
pr_debug("kmem_cache_create() for"
" tcm_loop_cmd_cache failed\n");
- return -ENOMEM;
+ goto out_destroy_workqueue;
}
ret = tcm_loop_alloc_core_bus();
if (ret)
- return ret;
+ goto out_destroy_cache;
ret = tcm_loop_register_configfs();
- if (ret) {
- tcm_loop_release_core_bus();
- return ret;
- }
+ if (ret)
+ goto out_release_core_bus;
return 0;
+
+out_release_core_bus:
+ tcm_loop_release_core_bus();
+out_destroy_cache:
+ kmem_cache_destroy(tcm_loop_cmd_cache);
+out_destroy_workqueue:
+ destroy_workqueue(tcm_loop_workqueue);
+out:
+ return ret;
}
static void __exit tcm_loop_fabric_exit(void)
@@ -1488,6 +1504,7 @@ static void __exit tcm_loop_fabric_exit(void)
tcm_loop_deregister_configfs();
tcm_loop_release_core_bus();
kmem_cache_destroy(tcm_loop_cmd_cache);
+ destroy_workqueue(tcm_loop_workqueue);
}
MODULE_DESCRIPTION("TCM loopback virtual Linux/SCSI fabric module");
diff --git a/drivers/target/loopback/tcm_loop.h b/drivers/target/loopback/tcm_loop.h
index 15a03644147..fc9bade9641 100644
--- a/drivers/target/loopback/tcm_loop.h
+++ b/drivers/target/loopback/tcm_loop.h
@@ -12,9 +12,9 @@ struct tcm_loop_cmd {
u32 sc_cmd_state;
/* Pointer to the CDB+Data descriptor from Linux/SCSI subsystem */
struct scsi_cmnd *sc;
- struct list_head *tl_cmd_list;
/* The TCM I/O descriptor that is accessed via container_of() */
struct se_cmd tl_se_cmd;
+ struct work_struct work;
/* Sense buffer that will be mapped into outgoing status */
unsigned char tl_sense_buf[TRANSPORT_SENSE_BUFFER];
};