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Commit 88ec4157 authored by Or Gerlitz's avatar Or Gerlitz Committed by Roland Dreier
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IB/iser: Remove redundant locking from iser scsi command response flow 



Currently the iSER receive completion flow takes the session lock
twice.  Optimize it to avoid the first one by letting
iser_task_rdma_finalize() be called only from the cleanup_task
callback invoked by iscsi_free_task, thus reducing the contention on
the session lock between the scsi command submission to the scsi
command completion flows.

Signed-off-by: default avatarOr Gerlitz <ogerlitz@voltaire.com>
Reviewed-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 962b4b52

drivers/infiniband/ulp/iser/iser_initiator.c

+0 −25
Original line number Diff line number Diff line
@@ -440,10 +440,7 @@ void iser_rcv_completion(struct iser_rx_desc *rx_desc, 
			 struct iser_conn *ib_conn)

{

	struct iscsi_iser_conn *conn = ib_conn->iser_conn;

	struct iscsi_task *task;

	struct iscsi_iser_task *iser_task;

	struct iscsi_hdr *hdr;

	unsigned char opcode;

	u64 rx_dma;

	int rx_buflen, outstanding, count, err;
@@ -464,28 +461,6 @@ void iser_rcv_completion(struct iser_rx_desc *rx_desc, 
	iser_dbg("op 0x%x itt 0x%x dlen %d\n", hdr->opcode,

			hdr->itt, (int)(rx_xfer_len - ISER_HEADERS_LEN));



	opcode = hdr->opcode & ISCSI_OPCODE_MASK;



	if (opcode == ISCSI_OP_SCSI_CMD_RSP) {

		spin_lock(&conn->iscsi_conn->session->lock);

		task = iscsi_itt_to_ctask(conn->iscsi_conn, hdr->itt);

		if (task)

			__iscsi_get_task(task);

		spin_unlock(&conn->iscsi_conn->session->lock);



		if (!task)

			iser_err("itt can't be matched to task!!! "

				 "conn %p opcode %d itt %d\n",

				 conn->iscsi_conn, opcode, hdr->itt);

		else {

			iser_task = task->dd_data;

			iser_dbg("itt %d task %p\n",hdr->itt, task);

			iser_task->status = ISER_TASK_STATUS_COMPLETED;

			iser_task_rdma_finalize(iser_task);

			iscsi_put_task(task);

		}

	}



	iscsi_iser_recv(conn->iscsi_conn, hdr,

		rx_desc->data, rx_xfer_len - ISER_HEADERS_LEN);