target: Remove transport_do_task_sg_chain() and associated detritus

Now that all fabrics are converted over to using se_cmd->t_data_sg
directly, we can drop the task sg chaining support.  With the modern
memory allocation in target core, task sg chaining is needless
overhead -- we would split up the main cmd sglist into pieces, and
then splice those pieces back together instead of just using the
original list directly.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 0 insertions, 70 deletions

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index db05c75..9fdc708 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -3699,76 +3699,6 @@ static inline sector_t transport_limit_task_sectors(
 	return sectors;
 }
 
-
-/*
- * This function can be used by HW target mode drivers to create a linked
- * scatterlist from all contiguously allocated struct se_task->task_sg[].
- * This is intended to be called during the completion path by TCM Core
- * when struct target_core_fabric_ops->check_task_sg_chaining is enabled.
- */
-void transport_do_task_sg_chain(struct se_cmd *cmd)
-{
-	struct scatterlist *sg_first = NULL;
-	struct scatterlist *sg_prev = NULL;
-	int sg_prev_nents = 0;
-	struct scatterlist *sg;
-	struct se_task *task;
-	u32 chained_nents = 0;
-	int i;
-
-	BUG_ON(!cmd->se_tfo->task_sg_chaining);
-
-	/*
-	 * Walk the struct se_task list and setup scatterlist chains
-	 * for each contiguously allocated struct se_task->task_sg[].
-	 */
-	list_for_each_entry(task, &cmd->t_task_list, t_list) {
-		if (!task->task_sg)
-			continue;
-
-		if (!sg_first) {
-			sg_first = task->task_sg;
-			chained_nents = task->task_sg_nents;
-		} else {
-			sg_chain(sg_prev, sg_prev_nents, task->task_sg);
-			chained_nents += task->task_sg_nents;
-		}
-		/*
-		 * For the padded tasks, use the extra SGL vector allocated
-		 * in transport_allocate_data_tasks() for the sg_prev_nents
-		 * offset into sg_chain() above.
-		 *
-		 * We do not need the padding for the last task (or a single
-		 * task), but in that case we will never use the sg_prev_nents
-		 * value below which would be incorrect.
-		 */
-		sg_prev_nents = (task->task_sg_nents + 1);
-		sg_prev = task->task_sg;
-	}
-	/*
-	 * Setup the starting pointer and total t_tasks_sg_linked_no including
-	 * padding SGs for linking and to mark the end.
-	 */
-	cmd->t_tasks_sg_chained = sg_first;
-	cmd->t_tasks_sg_chained_no = chained_nents;
-
-	pr_debug("Setup cmd: %p cmd->t_tasks_sg_chained: %p and"
-		" t_tasks_sg_chained_no: %u\n", cmd, cmd->t_tasks_sg_chained,
-		cmd->t_tasks_sg_chained_no);
-
-	for_each_sg(cmd->t_tasks_sg_chained, sg,
-			cmd->t_tasks_sg_chained_no, i) {
-
-		pr_debug("SG[%d]: %p page: %p length: %d offset: %d\n",
-			i, sg, sg_page(sg), sg->length, sg->offset);
-		if (sg_is_chain(sg))
-			pr_debug("SG: %p sg_is_chain=1\n", sg);
-		if (sg_is_last(sg))
-			pr_debug("SG: %p sg_is_last=1\n", sg);
-	}
-}
-EXPORT_SYMBOL(transport_do_task_sg_chain);
-
 /*
  * Break up cmd into chunks transport can handle
  */