From patchwork Tue Sep 13 19:57:15 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: 606081 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 04639ECAAD8 for ; Tue, 13 Sep 2022 19:57:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229681AbiIMT5f (ORCPT ); Tue, 13 Sep 2022 15:57:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45858 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229669AbiIMT53 (ORCPT ); Tue, 13 Sep 2022 15:57:29 -0400 Received: from mail-pj1-f45.google.com (mail-pj1-f45.google.com [209.85.216.45]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E4E072EFA for ; Tue, 13 Sep 2022 12:57:28 -0700 (PDT) Received: by mail-pj1-f45.google.com with SMTP id go6so8184421pjb.2 for ; Tue, 13 Sep 2022 12:57:28 -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; bh=Tc0Yo88uQfzIugZTyXtB+wWedqy1ibPn7Tcz49L6SPA=; b=hkWZEjEXxq4KyBgzrfccKRHJEG3K+KtE5ipkybnDgI0YqyeTxmlOP2m1w/pEmySod/ ScogAlqog1/THJKT4ThsIVVWcbC0FDK982VYiqHGmEwJrn+HXkx0zZK0hxnrhDs+nILW jxuOKJA+umF0IbvFUTXtxrepmN605Xt9uiYA3GY3yw0WTr2Wbt8VpBns2hDbIvKNa0z6 5IC7fNDjvDN6+jq+0YGwrr2WKmqRR3vhZdeRm2T3Zw+0ch36QZAoONT/NM9xFka0sYMT AWCFlfEOvfDkm2Ty7q6K1wRGpV99zv1j8H0tLuWqxNMkkWv/7N+0mpT17MvXSUxcFb30 qEvg== X-Gm-Message-State: ACrzQf0tkI4sUCAUzs+ph4jXHf4IUgkmMgfbYgUugLEPpVwrHtC1fLMU WAZnvDhzeA3hsbC50hhGcFWfIb5PR+k= X-Google-Smtp-Source: AMsMyM4jqtcQ3yehqWvebG5eWEKGTrh8SBz2rDyV7pJBHe85vufcwxCWt+PAmSS1eyAzfMtEJZrvyQ== X-Received: by 2002:a17:90a:9309:b0:1fa:d28b:3751 with SMTP id p9-20020a17090a930900b001fad28b3751mr846339pjo.189.1663099047644; Tue, 13 Sep 2022 12:57:27 -0700 (PDT) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:201:515b:d33a:21be:45a]) by smtp.gmail.com with ESMTPSA id p15-20020a1709027ecf00b0017825ab5320sm6739987plb.251.2022.09.13.12.57.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Sep 2022 12:57:26 -0700 (PDT) From: Bart Van Assche To: "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, Bart Van Assche , Christoph Hellwig , Ming Lei , Hannes Reinecke , John Garry , Mike Christie , Krzysztof Kozlowski , "James E.J. Bottomley" Subject: [PATCH v4 3/4] scsi: core: Introduce a new list for SCSI proc directory entries Date: Tue, 13 Sep 2022 12:57:15 -0700 Message-Id: <20220913195716.3966875-4-bvanassche@acm.org> X-Mailer: git-send-email 2.37.2.789.g6183377224-goog In-Reply-To: <20220913195716.3966875-1-bvanassche@acm.org> References: <20220913195716.3966875-1-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. Cc: Christoph Hellwig Cc: Ming Lei Cc: Hannes Reinecke Cc: John Garry Cc: Mike Christie Cc: Krzysztof Kozlowski Signed-off-by: Bart Van Assche --- drivers/scsi/scsi_priv.h | 4 +- drivers/scsi/scsi_proc.c | 111 +++++++++++++++++++++++++++++++++------ include/scsi/scsi_host.h | 12 ----- 3 files changed, 96 insertions(+), 31 deletions(-) diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h index f385b3f04d6e..be5d7c9b7f39 100644 --- a/drivers/scsi/scsi_priv.h +++ b/drivers/scsi/scsi_priv.h @@ -100,8 +100,8 @@ extern void scsi_evt_thread(struct work_struct *work); /* scsi_proc.c */ #ifdef CONFIG_SCSI_PROC_FS -extern void scsi_proc_hostdir_add(struct scsi_host_template *); -extern void scsi_proc_hostdir_rm(struct scsi_host_template *); +extern void 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 456b43097288..7dffa73d6f92 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); @@ -109,34 +152,57 @@ static const struct proc_ops proc_scsi_ops = { * Sets sht->proc_dir to the new directory. */ -void scsi_proc_hostdir_add(struct scsi_host_template *sht) +void scsi_proc_hostdir_add(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 = 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) + goto unlock; } + if (e->present++) { + e = NULL; + goto unlock; + } + 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); + e->present--; + goto unlock; + } + e->sht = sht; + list_add_tail(&e->entry, &scsi_proc_list); + e = NULL; +unlock: mutex_unlock(&global_host_template_mutex); + + kfree(e); } /** * 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); } @@ -148,16 +214,21 @@ 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) return; 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, @@ -170,13 +241,19 @@ 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 030faca947d2..fb8184d87384 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;