From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jitendra Bhivare Subject: RE: [PATCH 02/28] be2iscsi: Replace _bh with _irqsave/irqrestore Date: Tue, 9 Aug 2016 13:59:35 +0530 Message-ID: <2c0a32a2af7f12150da2818d0b0ec4d6@mail.gmail.com> References: <1469092085-14311-1-git-send-email-jitendra.bhivare@broadcom.com> <1469092085-14311-3-git-send-email-jitendra.bhivare@broadcom.com> <57A4DD34.4080000@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-ua0-f182.google.com ([209.85.217.182]:33080 "EHLO mail-ua0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751414AbcHII3i (ORCPT ); Tue, 9 Aug 2016 04:29:38 -0400 Received: by mail-ua0-f182.google.com with SMTP id 74so9103612uau.0 for ; Tue, 09 Aug 2016 01:29:37 -0700 (PDT) In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Martin K. Petersen" , Mike Christie Cc: linux-scsi@vger.kernel.org > -----Original Message----- > From: Martin K. Petersen [mailto:martin.petersen@oracle.com] > Sent: Tuesday, August 09, 2016 6:35 AM > To: Mike Christie > Cc: Jitendra Bhivare; linux-scsi@vger.kernel.org > Subject: Re: [PATCH 02/28] be2iscsi: Replace _bh with _irqsave/irqrestore > > >>>>> "Mike" == Mike Christie writes: > > >> In beiscsi_alloc_pdu, _bh versions of spin_lock are being used for > >> protecting SGLs and WRBs. _bh versions are needed as the function > >> gets invoked in process context and BLOCK_IOPOLL softirq. > >> > >> In spin_unlock_bh, after releasing the lock and enabling BH, > >> do_softirq is called which executes till last SOFTIRQ. > >> > >> beiscsi_alloc_pdu is called under session lock. Through block layer, > >> iSCSI stack in some cases send IOs with interrupts disabled. In such > >> paths, > > > Mike> What path is this? Is this with mq enabled or disabled? > > Jitendra? > > -- > Martin K. Petersen Oracle Linux Engineering [JB] Sorry for the delayed response, there was some issue with my mail client. There are paths block layer where IRQs are disabled with request_queue queue_lock. - blk_timeout_work : this triggers NOP-OUT thru' iscsi_eh_cmd_timed_out. - blk_execute_rq_nowait