From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755199AbeD3VWg (ORCPT ); Mon, 30 Apr 2018 17:22:36 -0400 Received: from mail-io0-f201.google.com ([209.85.223.201]:35380 "EHLO mail-io0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751772AbeD3VWc (ORCPT ); Mon, 30 Apr 2018 17:22:32 -0400 X-Google-Smtp-Source: AB8JxZrqTzpO0Kdv5aF4j6gfjsFzZ9ByKMM8AyxAdTd2SHN3WgSFs8CR93y7/OWGDCbWT8/6+72RekKtUOs/eA== MIME-Version: 1.0 Date: Mon, 30 Apr 2018 14:21:27 -0700 Message-Id: <20180430212127.54865-1-auradkar@google.com> X-Mailer: git-send-email 2.17.0.441.gb46fe60e1d-goog Subject: [RFC] [PATCH] Do not start queue from interrupt context From: Vikram Auradkar To: jejb@linux.vnet.ibm.com, martin.petersen@oracle.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, auradkar@google.com Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Vikram Auradkar Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Lockdep warning is seen when driver is handling a topology change event after drive removal. Starting queue eventually enables irq, which throws lockdep warning in scsi_request_fn. This change makes starting queues async. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/lockdep.c:2593 trace_hardirqs_on_caller+0x1bc/0x1d0() DEBUG_LOCKS_WARN_ON(current->hardirq_context) CPU: 0 PID: 0 Comm: swapper/0 Tainted: G O 3.11.10-dbg-DEV #1 Hardware name: Intel Grantley,Wellsburg/Ixion_QC_15, BIOS 2.50.0 01/21/2016 0000000000000000 ffff881fff803b28 ffffffffa4ea1bd5 ffff881fff803b78 ffffffffa491bdcc ffff881fff803b68 ffffffffa48ae464 00000000cc6405a0 0000000000000000 ffffffffa4805a50 ffff881f9b3ae000 0000000000000000 Call Trace: [] dump_stack+0x68/0x91 [] ? trace_hardirqs_on_caller+0x1bc/0x1d0 [] warn_slowpath_common+0x94/0xc0 [] ? _raw_spin_unlock_irq+0x30/0x50 [] warn_slowpath_fmt+0x46/0x50 [] trace_hardirqs_on_caller+0x1bc/0x1d0 [] trace_hardirqs_on+0xd/0x10 [] _raw_spin_unlock_irq+0x30/0x50 [] scsi_request_fn+0xaf/0x720 [] __blk_run_queue+0x37/0x50 [] blk_start_queue+0x3e/0x80 [] scsi_internal_device_unblock+0x3f/0x90 [] _scsih_ublock_io_device+0x87/0xd0 [mpt2sas] [] _scsih_tm_tr_send+0x185/0x340 [mpt2sas] [] mpt2sas_scsih_event_callback+0x3e0/0x840 [mpt2sas] [] _base_interrupt+0x2fa/0x950 [mpt2sas] [] ? trace_hardirqs_on_caller+0xab/0x1d0 [] ? trace_hardirqs_on+0xd/0x10 [] handle_irq_event_percpu+0x74/0x230 [] handle_irq_event+0x48/0x70 [] ? handle_edge_irq+0x1e/0x110 [] handle_edge_irq+0x77/0x110 [] handle_irq+0x22/0x40 [] do_IRQ+0x7f/0x110 [] common_interrupt+0x6f/0x6f [] ? __cpuidle_enter_state+0x7c/0x120 [] ? __cpuidle_enter_state+0x77/0x120 [] cpuidle_enter_state+0xd5/0x250 [] cpu_startup_entry+0xb8/0x1e0 [] rest_init+0xd6/0xe0 [] ? rest_init+0x5/0xe0 [] start_kernel+0x3ed/0x3fa [] ? repair_env_string+0x5e/0x5e [] x86_64_start_reservations+0x2a/0x2c [] x86_64_start_kernel+0x109/0x10d ---[ end trace 46d48ef4760a5d9c ]-- Signed-off-by: Vikram Auradkar --- drivers/scsi/scsi_lib.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index e9b4f279d29c..72c90233f261 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -3178,7 +3178,7 @@ void scsi_start_queue(struct scsi_device *sdev) blk_mq_unquiesce_queue(q); } else { spin_lock_irqsave(q->queue_lock, flags); - blk_start_queue(q); + blk_start_queue_async(q); spin_unlock_irqrestore(q->queue_lock, flags); } } -- 2.17.0.441.gb46fe60e1d-goog