From patchwork Thu Nov 26 13:29:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 11933769 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 233DDC71155 for ; Thu, 26 Nov 2020 13:30:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BBEE8221E9 for ; Thu, 26 Nov 2020 13:30:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="IRCzus7G"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="y1ZmSnJb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390100AbgKZNah (ORCPT ); Thu, 26 Nov 2020 08:30:37 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:56576 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390067AbgKZNag (ORCPT ); Thu, 26 Nov 2020 08:30:36 -0500 From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1606397433; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qrQH7xIDzf20GII/6KAvMh6TDcdBZRtUy7TTmRCIPTU=; b=IRCzus7GCSHg4/0BNYEGF0nlYHnXxAbunWrghpvrKt413OjNH9K+Kr03xDPVdutfJ1ibk9 u7aNoErqz9qI2ODI+toKoP+on89iNuXgD0V6RVuZ1/sP2+ZZ8j1+/HcNsJ/rnzWkx8pvqc o6jHvetZCCTpxosc6fEdaLXKg7vkHWdNbwVQAEFUTwV9LndHcwF+oaTzS7fC2n1iM8x2lX KK/IzDsIAwy4Lc1Ha9YcZmPPB/UduOrs9wW0uBcPSVKbVGdb3mU0N6PuqytTxkviIqfCx0 TdWy+forr/6KIGf7wyCVXfwjq8IS6AsFU+ygmX8fUQ5y7+oOL5ZpmOJjVbgovg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1606397433; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qrQH7xIDzf20GII/6KAvMh6TDcdBZRtUy7TTmRCIPTU=; b=y1ZmSnJbXqVnwIkJoNUYZg8/VEeX8tu+Y3EBrmnoZiATjFWMCUJXgy0nP9uQSS5i0YLbsw reKqvi/RrSuyJlDA== To: linux-scsi@vger.kernel.org Cc: Finn Thain , GR-QLogic-Storage-Upstream@marvell.com, Hannes Reinecke , Jack Wang , John Garry , linux-m68k@lists.linux-m68k.org, Manish Rangankar , Michael Schmitz , MPT-FusionLinux.pdl@broadcom.com, Nilesh Javali , Sathya Prakash , Sreekanth Reddy , Suganath Prabu Subramani , Vikram Auradkar , Xiang Chen , Xiaofei Tan , "James E . J . Bottomley" , "Martin K . Petersen" , Thomas Gleixner , "Ahmed S . Darwish" , Sebastian Andrzej Siewior Subject: [PATCH 07/14] scsi: qla4xxx: qla4_82xx_idc_lock(): Remove in_interrupt(). Date: Thu, 26 Nov 2020 14:29:45 +0100 Message-Id: <20201126132952.2287996-8-bigeasy@linutronix.de> In-Reply-To: <20201126132952.2287996-1-bigeasy@linutronix.de> References: <20201126132952.2287996-1-bigeasy@linutronix.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org From: "Ahmed S. Darwish" qla4_82xx_idc_lock() spins on a certain hardware state until it is updated. At the end of each spin, if in_interrupt() is true, it does 20 loops of cpu_relax(). Otherwise, it yields the CPU. While in_interrupt() is ill-defined and does not provide what the name suggests, it is not needed here: qla4_82xx_idc_lock() is always called from process context. Below is an analysis of its callers: - ql4_nx.c: qla4_82xx_need_reset_handler(), 1-second msleep() in a loop. - ql4_nx.c: qla4_82xx_isp_reset(), calls qla4_8xxx_device_state_handler(), which has multiple msleep()s. Beside direct calls, qla4_82xx_idc_lock() is also bound to isp_operations ->idc_lock() hook. Other functions which are bound to the same hook, e.g. qla4_83xx_drv_lock(), also have an msleep(). For completeness, below is an analysis of all callers of that hook: - ql4_83xx.c: qla4_83xx_need_reset_handler(), has an msleep() - ql4_83xx.c: qla4_83xx_isp_reset(), calls qla4_8xxx_device_state_handler(), which has multiple msleep()s. - ql4_83xx.c: qla4_83xx_disable_pause(), all process context callers: => ql4_mbx.c: qla4xxx_mailbox_command(), msleep(), mutex_lock() => ql4_os.c: qla4xxx_recover_adapter(), schedule_timeout() in loop => ql4_os.c: qla4xxx_do_dpc(), workqueue context - ql4_attr.c: qla4_8xxx_sysfs_write_fw_dump(), sysfs bin_attribute ->write() hook, process context - ql4_mbx.c: qla4xxx_mailbox_command(), earlier discussed - ql4_nx.c: qla4_8xxx_device_bootstrap(), callers: => ql4_83xx.c: qla4_83xx_need_reset_handler(), process, msleep() => ql4_nx.c: qla4_8xxx_device_state_handler(), earlier discussed - ql4_nx.c: qla4_8xxx_need_qsnt_handler(), callers: => ql4_nx.c: qla4_8xxx_device_state_handler(), multipe msleep()s => ql4_os.c: qla4xxx_do_dpc(), workqueue context - ql4_nx.c: qla4_8xxx_update_idc_reg(), callers: => ql4_nx.c: qla4_8xxx_device_state_handler(), earlier discussed => ql4_os.c: qla4_8xxx_error_recovery(), only called by qla4xxx_pci_slot_reset(), which is bound to PCI ->slot_reset() process-context hook - ql4_nx.c: qla4_8xxx_device_state_handler(), earlier discussed - ql4_os.c: qla4xxx_recover_adapter(), earlier discussed - ql4_os.c: qla4xxx_do_dpc(), earlier discussed Remove the in_interrupt() check. Mark, qla4_82xx_idc_lock(), and the ->idc_lock() hook itself, with "Context: task, can sleep". Change qla4_82xx_idc_lock() implementation to sleep 100ms, instead of a schedule(), for each spin. This is more deterministic, and it matches other PCI HW locking functions in the driver. Signed-off-by: Ahmed S. Darwish Cc: Nilesh Javali Cc: Manish Rangankar Cc: Signed-off-by: Sebastian Andrzej Siewior Reviewed-by: Daniel Wagner --- drivers/scsi/qla4xxx/ql4_def.h | 2 +- drivers/scsi/qla4xxx/ql4_nx.c | 14 +++++--------- 2 files changed, 6 insertions(+), 10 deletions(-) diff --git a/drivers/scsi/qla4xxx/ql4_def.h b/drivers/scsi/qla4xxx/ql4_def.h index f5b382ed0a1b2..9210547483886 100644 --- a/drivers/scsi/qla4xxx/ql4_def.h +++ b/drivers/scsi/qla4xxx/ql4_def.h @@ -435,7 +435,7 @@ struct isp_operations { void (*wr_reg_direct) (struct scsi_qla_host *, ulong, uint32_t); int (*rd_reg_indirect) (struct scsi_qla_host *, uint32_t, uint32_t *); int (*wr_reg_indirect) (struct scsi_qla_host *, uint32_t, uint32_t); - int (*idc_lock) (struct scsi_qla_host *); + int (*idc_lock) (struct scsi_qla_host *); /* Context: task, can sleep */ void (*idc_unlock) (struct scsi_qla_host *); void (*rom_lock_recovery) (struct scsi_qla_host *); void (*queue_mailbox_command) (struct scsi_qla_host *, uint32_t *, int); diff --git a/drivers/scsi/qla4xxx/ql4_nx.c b/drivers/scsi/qla4xxx/ql4_nx.c index da903a545b2c0..4362d0ebe0e15 100644 --- a/drivers/scsi/qla4xxx/ql4_nx.c +++ b/drivers/scsi/qla4xxx/ql4_nx.c @@ -512,12 +512,15 @@ int qla4_82xx_md_wr_32(struct scsi_qla_host *ha, uint32_t off, uint32_t data) * * General purpose lock used to synchronize access to * CRB_DEV_STATE, CRB_DEV_REF_COUNT, etc. + * + * Context: task, can sleep **/ int qla4_82xx_idc_lock(struct scsi_qla_host *ha) { - int i; int done = 0, timeout = 0; + might_sleep(); + while (!done) { /* acquire semaphore5 from PCI HW block */ done = qla4_82xx_rd_32(ha, QLA82XX_PCIE_REG(PCIE_SEM5_LOCK)); @@ -527,14 +530,7 @@ int qla4_82xx_idc_lock(struct scsi_qla_host *ha) return -1; timeout++; - - /* Yield CPU */ - if (!in_interrupt()) - schedule(); - else { - for (i = 0; i < 20; i++) - cpu_relax(); /*This a nop instr on i386*/ - } + msleep(100); } return 0; }