From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Nicholas A. Bellinger" Subject: [PATCH 0/3] megaraid_sas: Convert to host_lock less w/ interrupts disabled internally Date: Sat, 27 Nov 2010 23:17:33 -0800 Message-ID: <1290928656-31116-1-git-send-email-nab@linux-iscsi.org> Return-path: Received: from nm21.bullet.mail.sp2.yahoo.com ([98.139.91.91]:32770 "HELO nm21.bullet.mail.sp2.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751538Ab0K1HR5 (ORCPT ); Sun, 28 Nov 2010 02:17:57 -0500 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-scsi , Hannes Reinecke , Bo Yang Cc: Christoph Hellwig , James Bottomley , Nicholas Bellinger From: Nicholas Bellinger Greetings Hannes, Bo and Co, This series converts megaraid_sas to run in modern host_lock-less mode for >= .37-rc3+ with interrupts disabled internally around megasas_instance->hba_lock. This series is currently living in lio-core-2.6.git/lock_less-LLDs-for-38-v2, and is intended for .38 mainline code. The first patch adds a handful of missing barriers around instance->fw_outstanding usage w/ atomic_add() and atomic_dec(). The second converts instance->issuepend_done to an atomic_t, along with the necessary assignments in order to run w/ Scsi_Host->host_lock, and without instance->hba_lock. The third patch does the actual conversion, and adds a __megasas_get_cmd() usased by megasas_queue_command() w/ instance->hba_lock, along with being held for megasas_build_ldio() and megasas_build_dcdb() in order to locate the proper frame for struct megasas_cmd. This is really the one major change in order to get host_lock-less to function with interrupts disabled around hba_lock. So far this has been tested with Hannes's QEMU 8708EM2 HBA emulation with TCM_Loop backends using SG_IO from KVM host in a paired Host/Guest .37-rc3 environment. This has not been tested on real silicon yet, but I believe this series should be working there as well. Comments are welcome, thanks! Signed-off-by: Nicholas A. Bellinger Nicholas Bellinger (3): megaraid_sas: Add smp_mb__after_atomic_*() for instance->fw_outstanding megaraid_sas: Convert instance->issuepend_done to atomic_t megaraid_sas: Convert SHT->queuecommand() to run host_lock-less drivers/scsi/megaraid/megaraid_sas.c | 84 ++++++++++++++++++++++----------- drivers/scsi/megaraid/megaraid_sas.h | 2 +- 2 files changed, 57 insertions(+), 29 deletions(-) -- 1.7.2.3