From mboxrd@z Thu Jan 1 00:00:00 1970 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 28117ECAAA1 for ; Tue, 30 Aug 2022 21:05:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231429AbiH3VFa (ORCPT ); Tue, 30 Aug 2022 17:05:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231439AbiH3VFW (ORCPT ); Tue, 30 Aug 2022 17:05:22 -0400 Received: from mail-pf1-f178.google.com (mail-pf1-f178.google.com [209.85.210.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 281FD3E757 for ; Tue, 30 Aug 2022 14:05:21 -0700 (PDT) Received: by mail-pf1-f178.google.com with SMTP id 199so12484597pfz.2 for ; Tue, 30 Aug 2022 14:05:21 -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; bh=pwQoKph6R5CnYoWiwZ4ugwErE1NaIPZGRnuF9mUQaKY=; b=D6lS/Df/4+L+zS/jU9QnMLZEMnis9NrZpkKg43YePcnLgjX4ucYIyY1pJlm41L1f82 ya6X07fLfgwk446ZjHWbwWjUQPZu9CZbZqlgiI+pXyBJyBWfTz52Yc0xzlko+0TLqimo WBKzLoMWAvoqHoQYfUhtaAG05EWNyWNayQqdAqMJbDUkL8wgftXXkLDtwb2JZnBdp3tc pl8+so3N5uIeOPdqFu57muFLCw+GQjxrVLm03NF2jsnAfvuuqnOAFzuza3oP7zsr/95c 3eriLQ7xcRR18N4isA3EgIXcHYmdwDHHdZ7QCxswtqX6/nQkrvP5O9uISAjzO9W/VPxl aWXA== X-Gm-Message-State: ACgBeo2gDriAtZr299mbbOf1EQd9eQW4xdI9uIJUND2ac0hXOQsrJDXg dXlGnOzPutlFUvBy45dT248= X-Google-Smtp-Source: AA6agR7FwH+3gzeiP6oTMJwDhs2MNwajwE6EnQv5OKmBkuwWCVwjC0LbINieyFjunUM0TP+ZMzyQJA== X-Received: by 2002:a63:a55e:0:b0:42c:202c:5c5a with SMTP id r30-20020a63a55e000000b0042c202c5c5amr9579477pgu.39.1661893520187; Tue, 30 Aug 2022 14:05:20 -0700 (PDT) Received: from bvanassche-glaptop2.roam.corp.google.com ([12.219.165.6]) by smtp.gmail.com with ESMTPSA id z5-20020a170903018500b00174da27b8e3sm4612841plg.8.2022.08.30.14.05.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Aug 2022 14:05:19 -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 Subject: [PATCH v2 2/2] scsi: core: Introduce a new list for SCSI proc directory entries Date: Tue, 30 Aug 2022 14:05:09 -0700 Message-Id: <20220830210509.1919493-3-bvanassche@acm.org> X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog In-Reply-To: <20220830210509.1919493-1-bvanassche@acm.org> References: <20220830210509.1919493-1-bvanassche@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Bart Van Assche --- drivers/scsi/scsi_proc.c | 97 ++++++++++++++++++++++++++++++++++------ include/scsi/scsi_host.h | 12 ----- 2 files changed, 83 insertions(+), 26 deletions(-) diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c index eeb9261c93f7..702b78963c2e 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 char 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(scsi_template_proc_dir); @@ -111,17 +154,35 @@ static const struct proc_ops proc_scsi_ops = { void scsi_proc_hostdir_add(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); + goto unlock; } + e->sht = sht; + list_add_tail(&e->entry, &scsi_proc_list); + e = NULL; +unlock: mutex_unlock(&global_host_template_mutex); + + kfree(e); } /** @@ -130,13 +191,17 @@ void scsi_proc_hostdir_add(struct scsi_host_template *sht) */ void scsi_proc_hostdir_rm(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); } @@ -149,15 +214,17 @@ 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; + struct scsi_proc_entry *e; struct proc_dir_entry *p; char name[10]; - if (!sht->proc_dir) + 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 +237,15 @@ void scsi_proc_host_add(struct Scsi_Host *shost) */ void scsi_proc_host_rm(struct Scsi_Host *shost) { + struct scsi_proc_entry *e; char name[10]; - if (!shost->hostt->proc_dir) + e = scsi_lookup_proc_entry(shost->hostt); + 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 c2b8427e0305..f2294d44013c 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;