target: Drop se_device TCQ queue_depth usage from I/O path
Historically, pSCSI devices have been the ones that required target-core
to enforce a per se_device->depth_left. This patch changes target-core
to no longer (by default) enforce a per se_device->depth_left or sleep in
transport_tcq_window_closed() when we out of queue slots for all backend
export cases.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 1f74de2..0c5992f 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -1132,8 +1132,6 @@
*/
int se_dev_set_queue_depth(struct se_device *dev, u32 queue_depth)
{
- u32 orig_queue_depth = dev->queue_depth;
-
if (atomic_read(&dev->dev_export_obj.obj_access_count)) {
pr_err("dev[%p]: Unable to change SE Device TCQ while"
" dev_export_obj: %d count exists\n", dev,
@@ -1167,11 +1165,6 @@
}
dev->se_sub_dev->se_dev_attrib.queue_depth = dev->queue_depth = queue_depth;
- if (queue_depth > orig_queue_depth)
- atomic_add(queue_depth - orig_queue_depth, &dev->depth_left);
- else if (queue_depth < orig_queue_depth)
- atomic_sub(orig_queue_depth - queue_depth, &dev->depth_left);
-
pr_debug("dev[%p]: SE Device TCQ Depth changed to: %u\n",
dev, queue_depth);
return 0;
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index b73a399..d35467d 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -350,7 +350,6 @@
* scsi_device_put() and the pdv->pdv_sd cleared.
*/
pdv->pdv_sd = sd;
-
dev = transport_add_device_to_core_hba(hba, &pscsi_template,
se_dev, dev_flags, pdv,
&dev_limits, NULL, NULL);
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 1cc7e92..7c2def7 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -691,12 +691,6 @@
struct se_cmd *cmd = task->task_se_cmd;
struct se_device *dev = cmd->se_dev;
unsigned long flags;
-#if 0
- pr_debug("task: %p CDB: 0x%02x obj_ptr: %p\n", task,
- cmd->t_task_cdb[0], dev);
-#endif
- if (dev)
- atomic_inc(&dev->depth_left);
spin_lock_irqsave(&cmd->t_state_lock, flags);
task->task_flags &= ~TF_ACTIVE;
@@ -971,9 +965,8 @@
break;
}
- *bl += sprintf(b + *bl, " Execute/Left/Max Queue Depth: %d/%d/%d",
- atomic_read(&dev->execute_tasks), atomic_read(&dev->depth_left),
- dev->queue_depth);
+ *bl += sprintf(b + *bl, " Execute/Max Queue Depth: %d/%d",
+ atomic_read(&dev->execute_tasks), dev->queue_depth);
*bl += sprintf(b + *bl, " SectorSize: %u MaxSectors: %u\n",
dev->se_sub_dev->se_dev_attrib.block_size, dev->se_sub_dev->se_dev_attrib.max_sectors);
*bl += sprintf(b + *bl, " ");
@@ -1328,9 +1321,6 @@
spin_lock_init(&dev->se_port_lock);
spin_lock_init(&dev->se_tmr_lock);
spin_lock_init(&dev->qf_cmd_lock);
-
- dev->queue_depth = dev_limits->queue_depth;
- atomic_set(&dev->depth_left, dev->queue_depth);
atomic_set(&dev->dev_ordered_id, 0);
se_dev_set_default_attribs(dev, dev_limits);
@@ -1982,18 +1972,6 @@
spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
}
-static inline int transport_tcq_window_closed(struct se_device *dev)
-{
- if (dev->dev_tcq_window_closed++ <
- PYX_TRANSPORT_WINDOW_CLOSED_THRESHOLD) {
- msleep(PYX_TRANSPORT_WINDOW_CLOSED_WAIT_SHORT);
- } else
- msleep(PYX_TRANSPORT_WINDOW_CLOSED_WAIT_LONG);
-
- wake_up_interruptible(&dev->dev_queue_obj.thread_wq);
- return 0;
-}
-
/*
* Called from Fabric Module context from transport_execute_tasks()
*
@@ -2126,16 +2104,7 @@
struct se_task *task = NULL;
unsigned long flags;
- /*
- * Check if there is enough room in the device and HBA queue to send
- * struct se_tasks to the selected transport.
- */
check_depth:
- if (!atomic_read(&dev->depth_left))
- return transport_tcq_window_closed(dev);
-
- dev->dev_tcq_window_closed = 0;
-
spin_lock_irq(&dev->execute_task_lock);
if (list_empty(&dev->execute_task_list)) {
spin_unlock_irq(&dev->execute_task_lock);
@@ -2146,10 +2115,7 @@
__transport_remove_task_from_execute_queue(task, dev);
spin_unlock_irq(&dev->execute_task_lock);
- atomic_dec(&dev->depth_left);
-
cmd = task->task_se_cmd;
-
spin_lock_irqsave(&cmd->t_state_lock, flags);
task->task_flags |= (TF_ACTIVE | TF_SENT);
atomic_inc(&cmd->t_task_cdbs_sent);
@@ -2170,7 +2136,6 @@
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
atomic_set(&cmd->t_transport_sent, 0);
transport_stop_tasks_for_cmd(cmd);
- atomic_inc(&dev->depth_left);
transport_generic_request_failure(cmd);
}
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 28190dc..cd4caf3 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -798,7 +798,6 @@
spinlock_t stats_lock;
/* Active commands on this virtual SE device */
atomic_t simple_cmds;
- atomic_t depth_left;
atomic_t dev_ordered_id;
atomic_t execute_tasks;
atomic_t dev_ordered_sync;