Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756883AbbEVIAH (ORCPT ); Fri, 22 May 2015 04:00:07 -0400 Received: from mail-ob0-f172.google.com ([209.85.214.172]:36055 "EHLO mail-ob0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754712AbbEVIAE (ORCPT ); Fri, 22 May 2015 04:00:04 -0400 From: "Nicholas A. Bellinger" To: target-devel Cc: linux-scsi , linux-kernel , Christoph Hellwig , Hannes Reinecke , Sagi Grimberg , Nicholas Bellinger Subject: [RFC 0/2] target: Add TFO->complete_irq queue_work bypass Date: Fri, 22 May 2015 07:57:24 +0000 Message-Id: <1432281446-31080-1-git-send-email-nab@daterainc.com> X-Mailer: git-send-email 1.7.2.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1843 Lines: 56 From: Nicholas Bellinger Hi HCH & Co, Here is RFC code for adding target_core_fabric_ops->complete_irq bypass that allows fabrics to invoke response callbacks directly from target_complete_cmd() IRQ context. It breaks up existing target_complete_ok_work() code into three pieces: - transport_complete_task_attr() - target_complete_ok_pre() - target_complete_irq() and allows target_complete_irq() be called directly from IRQ context if no special case se_cmd handling requirements exist. The three cases that trigger queue_work() process context are: - non GOOD status - ORDERED task sync - non NULL se_cmd->transport_complete_callback() It also includes converting target_restart_delayed_cmds() to use llist_head, and checking within transport_complete_task_attr() to determine if dev_ordered_sync is non zero, ahead of doing the llist_del_all() -> cmpxchg of outstanding ordered tags. This allows loopback LLD code to bypass the extra queue_work, and invoke it's ->scsi_done() callback directly from IRQ context. WDYT..? --nab Nicholas Bellinger (2): target: Add support for fabric IRQ completion loopback: Enable TFO->complete_irq for fast-path ->scsi_done drivers/target/loopback/tcm_loop.c | 1 + drivers/target/target_core_device.c | 2 +- drivers/target/target_core_tpg.c | 1 + drivers/target/target_core_transport.c | 165 ++++++++++++++++++++++++--------- include/target/target_core_base.h | 5 +- include/target/target_core_fabric.h | 1 + 6 files changed, 127 insertions(+), 48 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/