From patchwork Sat Oct 15 00:24:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 615374 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42BD9C43217 for ; Sat, 15 Oct 2022 00:24:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229681AbiJOAYm (ORCPT ); Fri, 14 Oct 2022 20:24:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229734AbiJOAYk (ORCPT ); Fri, 14 Oct 2022 20:24:40 -0400 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A4C9CB8C for ; Fri, 14 Oct 2022 17:24:36 -0700 (PDT) Received: by mail-pl1-f171.google.com with SMTP id n7so6169470plp.1 for ; Fri, 14 Oct 2022 17:24:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ia+y/8O8+wjdy0kvrz1w5K81uYbGrTon6wMcNG0Yng8=; b=3oU+QFJ+lNSS1wSHI/3/ijGwxlNCpfUMW4J7XSoVlTwCEF+l4NLC6jDiEOLijI00u0 R7rNoxsiqLW8ntiwYs/VQnCetV1yZAnYsj18QR2mhYASTHpFa++eVYZzvmypvq7pS2qW cql79vOfrPlkNS60knrBdpP58FsSbnR9+tYUs0F2O2irxm5i96mt6mdVPhunfHnLn8J2 fyRBjQPGCDxztN5RItuL2IzB/NfoGoV7QPLMKJB02aRgoig/i2Z3R6H931X0I2MPfhmy S7zkluwt/Kb2rkj8P9yj0Nl1iVitPQ3Iu01wMuSrr7yfpNxTcERdDgA3nW0vGOCkAzrn q16Q== X-Gm-Message-State: ACrzQf0Z7wXvxanADv0rAxQyWJNUAjOO0nawODiSZ397z3vEPUEjiTRT tg9s9sgUNptbxSYgTQUOaMo= X-Google-Smtp-Source: AMsMyM6qt8tV37rx389v8Nt/FvBb4GOC8cbFJiTfBesS75ZKEENa8WemoiCUDLX6bOnt5I+eGV2qqg== X-Received: by 2002:a17:902:d483:b0:182:cb98:26e8 with SMTP id c3-20020a170902d48300b00182cb9826e8mr257865plg.73.1665793476199; Fri, 14 Oct 2022 17:24:36 -0700 (PDT) Received: from asus.hsd1.ca.comcast.net ([98.51.102.78]) by smtp.gmail.com with ESMTPSA id y17-20020a634951000000b0046a1c832e9fsm1937953pgk.34.2022.10.14.17.24.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Oct 2022 17:24:35 -0700 (PDT) From: Bart Van Assche To: "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, Bart Van Assche , John Garry , Christoph Hellwig , Ming Lei , Hannes Reinecke , Mike Christie , Krzysztof Kozlowski Subject: [PATCH v7 4/8] scsi: core: Introduce a new list for SCSI proc directory entries Date: Fri, 14 Oct 2022 17:24:14 -0700 Message-Id: <20221015002418.30955-5-bvanassche@acm.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221015002418.30955-1-bvanassche@acm.org> References: <20221015002418.30955-1-bvanassche@acm.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Instead of using scsi_host_template members to track the SCSI proc directory entries, track these entries in a list. This patch changes the time needed for looking up the proc dir pointer from O(1) into O(n). I think this is acceptable since the number of SCSI host adapter types per host is usually small (less than ten). This patch has been tested by attaching two USB storage devices to a qemu host: $ grep -aH . /proc/scsi/usb-storage/* /proc/scsi/usb-storage/7: Host scsi7: usb-storage /proc/scsi/usb-storage/7: Vendor: QEMU /proc/scsi/usb-storage/7: Product: QEMU USB HARDDRIVE /proc/scsi/usb-storage/7:Serial Number: 1-0000:00:02.1:00.0-6 /proc/scsi/usb-storage/7: Protocol: Transparent SCSI /proc/scsi/usb-storage/7: Transport: Bulk /proc/scsi/usb-storage/7: Quirks: SANE_SENSE /proc/scsi/usb-storage/8: Host scsi8: usb-storage /proc/scsi/usb-storage/8: Vendor: QEMU /proc/scsi/usb-storage/8: Product: QEMU USB HARDDRIVE /proc/scsi/usb-storage/8:Serial Number: 1-0000:00:02.1:00.0-7 /proc/scsi/usb-storage/8: Protocol: Transparent SCSI /proc/scsi/usb-storage/8: Transport: Bulk /proc/scsi/usb-storage/8: Quirks: SANE_SENSE This patch prepares for constifying most SCSI host templates. Reviewed-by: John Garry Cc: Christoph Hellwig Cc: Ming Lei Cc: Hannes Reinecke Cc: Mike Christie Cc: Krzysztof Kozlowski Signed-off-by: Bart Van Assche --- drivers/scsi/scsi_priv.h | 4 +- drivers/scsi/scsi_proc.c | 121 ++++++++++++++++++++++++++++++++------- include/scsi/scsi_host.h | 12 ---- 3 files changed, 102 insertions(+), 35 deletions(-) diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h index 494f48e03e90..96284a0e13fe 100644 --- a/drivers/scsi/scsi_priv.h +++ b/drivers/scsi/scsi_priv.h @@ -111,8 +111,8 @@ extern void scsi_evt_thread(struct work_struct *work); /* scsi_proc.c */ #ifdef CONFIG_SCSI_PROC_FS -extern int scsi_proc_hostdir_add(struct scsi_host_template *); -extern void scsi_proc_hostdir_rm(struct scsi_host_template *); +extern int scsi_proc_hostdir_add(const struct scsi_host_template *); +extern void scsi_proc_hostdir_rm(const struct scsi_host_template *); extern void scsi_proc_host_add(struct Scsi_Host *); extern void scsi_proc_host_rm(struct Scsi_Host *); extern int scsi_init_procfs(void); diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c index 8c84f1a74773..4a6eb1741be0 100644 --- a/drivers/scsi/scsi_proc.c +++ b/drivers/scsi/scsi_proc.c @@ -43,8 +43,23 @@ static struct proc_dir_entry *proc_scsi; -/* Protect sht->present and sht->proc_dir */ +/* Protects scsi_proc_list */ static DEFINE_MUTEX(global_host_template_mutex); +static LIST_HEAD(scsi_proc_list); + +/** + * struct scsi_proc_entry - (host template, SCSI proc dir) association + * @entry: entry in scsi_proc_list. + * @sht: SCSI host template associated with the procfs directory. + * @proc_dir: procfs directory associated with the SCSI host template. + * @present: Number of SCSI hosts instantiated for @sht. + */ +struct scsi_proc_entry { + struct list_head entry; + const struct scsi_host_template *sht; + struct proc_dir_entry *proc_dir; + unsigned int present; +}; static ssize_t proc_scsi_host_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) @@ -83,6 +98,32 @@ static int proc_scsi_host_open(struct inode *inode, struct file *file) 4 * PAGE_SIZE); } +static struct scsi_proc_entry * +__scsi_lookup_proc_entry(const struct scsi_host_template *sht) +{ + struct scsi_proc_entry *e; + + lockdep_assert_held(&global_host_template_mutex); + + list_for_each_entry(e, &scsi_proc_list, entry) + if (e->sht == sht) + return e; + + return NULL; +} + +static struct scsi_proc_entry * +scsi_lookup_proc_entry(const struct scsi_host_template *sht) +{ + struct scsi_proc_entry *e; + + mutex_lock(&global_host_template_mutex); + e = __scsi_lookup_proc_entry(sht); + mutex_unlock(&global_host_template_mutex); + + return e; +} + /** * scsi_template_proc_dir() - returns the procfs dir for a SCSI host template * @sht: SCSI host template pointer. @@ -90,7 +131,9 @@ static int proc_scsi_host_open(struct inode *inode, struct file *file) struct proc_dir_entry * scsi_template_proc_dir(const struct scsi_host_template *sht) { - return sht->proc_dir; + struct scsi_proc_entry *e = scsi_lookup_proc_entry(sht); + + return e ? e->proc_dir : NULL; } EXPORT_SYMBOL_GPL(scsi_template_proc_dir); @@ -108,24 +151,41 @@ static const struct proc_ops proc_scsi_ops = { * * Sets sht->proc_dir to the new directory. */ -int scsi_proc_hostdir_add(struct scsi_host_template *sht) +int scsi_proc_hostdir_add(const struct scsi_host_template *sht) { - int ret = 0; + struct scsi_proc_entry *e; + int ret; if (!sht->show_info) return 0; mutex_lock(&global_host_template_mutex); - if (!sht->present++) { - sht->proc_dir = proc_mkdir(sht->proc_name, proc_scsi); - if (!sht->proc_dir) { - printk(KERN_ERR "%s: proc_mkdir failed for %s\n", - __func__, sht->proc_name); + e = __scsi_lookup_proc_entry(sht); + if (!e) { + e = kzalloc(sizeof(*e), GFP_KERNEL); + if (!e) { ret = -ENOMEM; + goto unlock; } } + if (e->present++) + goto success; + e->proc_dir = proc_mkdir(sht->proc_name, proc_scsi); + if (!e->proc_dir) { + printk(KERN_ERR "%s: proc_mkdir failed for %s\n", __func__, + sht->proc_name); + ret = -ENOMEM; + goto unlock; + } + e->sht = sht; + list_add_tail(&e->entry, &scsi_proc_list); +success: + e = NULL; + ret = 0; +unlock: mutex_unlock(&global_host_template_mutex); + kfree(e); return ret; } @@ -133,15 +193,19 @@ int scsi_proc_hostdir_add(struct scsi_host_template *sht) * scsi_proc_hostdir_rm - remove directory in /proc for a scsi host * @sht: owner of directory */ -void scsi_proc_hostdir_rm(struct scsi_host_template *sht) +void scsi_proc_hostdir_rm(const struct scsi_host_template *sht) { + struct scsi_proc_entry *e; + if (!sht->show_info) return; mutex_lock(&global_host_template_mutex); - if (!--sht->present && sht->proc_dir) { + e = __scsi_lookup_proc_entry(sht); + if (e && !--e->present) { remove_proc_entry(sht->proc_name, proc_scsi); - sht->proc_dir = NULL; + list_del(&e->entry); + kfree(e); } mutex_unlock(&global_host_template_mutex); } @@ -153,20 +217,29 @@ void scsi_proc_hostdir_rm(struct scsi_host_template *sht) */ void scsi_proc_host_add(struct Scsi_Host *shost) { - struct scsi_host_template *sht = shost->hostt; + const struct scsi_host_template *sht = shost->hostt; + struct scsi_proc_entry *e; struct proc_dir_entry *p; char name[10]; - if (!sht->proc_dir) + if (!sht->show_info) return; + e = scsi_lookup_proc_entry(sht); + if (!e) + goto err; + sprintf(name,"%d", shost->host_no); - p = proc_create_data(name, S_IRUGO | S_IWUSR, - sht->proc_dir, &proc_scsi_ops, shost); + p = proc_create_data(name, S_IRUGO | S_IWUSR, e->proc_dir, + &proc_scsi_ops, shost); if (!p) - printk(KERN_ERR "%s: Failed to register host %d in" - "%s\n", __func__, shost->host_no, - sht->proc_name); + goto err; + return; + +err: + shost_printk(KERN_ERR, shost, + "%s: Failed to register host (%s failed)\n", __func__, + e ? "proc_create_data()" : "scsi_proc_hostdir_add()"); } /** @@ -175,13 +248,19 @@ void scsi_proc_host_add(struct Scsi_Host *shost) */ void scsi_proc_host_rm(struct Scsi_Host *shost) { + const struct scsi_host_template *sht = shost->hostt; + struct scsi_proc_entry *e; char name[10]; - if (!shost->hostt->proc_dir) + if (!sht->show_info) + return; + + e = scsi_lookup_proc_entry(sht); + if (!e) return; sprintf(name,"%d", shost->host_no); - remove_proc_entry(name, shost->hostt->proc_dir); + remove_proc_entry(name, e->proc_dir); } /** * proc_print_scsidevice - return data about this host diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 3854ffcb0b3e..e71436183c0d 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -357,12 +357,6 @@ struct scsi_host_template { */ const char *proc_name; - /* - * Used to store the procfs directory if a driver implements the - * show_info method. - */ - struct proc_dir_entry *proc_dir; - /* * This determines if we will use a non-interrupt driven * or an interrupt driven scheme. It is set to the maximum number @@ -423,12 +417,6 @@ struct scsi_host_template { */ short cmd_per_lun; - /* - * present contains counter indicating how many boards of this - * type were found when we did the scan. - */ - unsigned char present; - /* If use block layer to manage tags, this is tag allocation policy */ int tag_alloc_policy;