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>

1 files changed, 0 insertions, 7 deletions

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 1f74de25a92f..0c5992f0d946 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -1132,8 +1132,6 @@ int se_dev_set_emulate_rest_reord(struct se_device *dev, int flag)
  */
 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 @@ int se_dev_set_queue_depth(struct se_device *dev, u32 queue_depth)
         }
 
         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;