From patchwork Mon Jul 5 08:19:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: William Breathitt Gray X-Patchwork-Id: 12358437 X-Patchwork-Delegate: jic23@cam.ac.uk 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 2329BC07E9C for ; Mon, 5 Jul 2021 08:20:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D0E8613F3 for ; Mon, 5 Jul 2021 08:20:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230360AbhGEIXV (ORCPT ); Mon, 5 Jul 2021 04:23:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54302 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230301AbhGEIXT (ORCPT ); Mon, 5 Jul 2021 04:23:19 -0400 Received: from mail-pj1-x1033.google.com (mail-pj1-x1033.google.com [IPv6:2607:f8b0:4864:20::1033]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 678FBC061574; Mon, 5 Jul 2021 01:20:42 -0700 (PDT) Received: by mail-pj1-x1033.google.com with SMTP id x21-20020a17090aa395b029016e25313bfcso11340817pjp.2; Mon, 05 Jul 2021 01:20:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=eJ5JyREZ5LpvYsK+0QASIvJ867/NXe9Cl2Yvt7ud23M=; b=RZX/aDqOz1vpn3LnYmIfFKdCCfW9QoOgr8SuZYs2YISBtw40q6xjy6GobZ2c2fH35r /HmSEQ7BLqid1XFINBFPY6rM8ot7AfjjJq+cfttLAQlJ4ebTpbqaeNZ5WBvJMNzONgGm bfisqgFcACnnvlIX2GwS2M9oCFkMdQr2egtne1J3vdBHdK7R0EImjDqKfyc+WIGMM6CK rNAqM2ATbt3HLYpPd5UxELrRLzGFG5gpyVdpQom4qClkVW4pm73pS7Zn33s5PJ/Qm7+Z mo/9Sr1MvS3yBgTxlw8rKf4/HafUAugGHrjkT13Ix8ExjowlQV+sfi9WoG3QKXswWwHx 9wDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=eJ5JyREZ5LpvYsK+0QASIvJ867/NXe9Cl2Yvt7ud23M=; b=S0ab49nx+BDk7qsRfN3dJMiFj0h/aqxafCqpOIGUkKkm1UlLnsAW8t4juz9Ods859B RQl7x6LZ9uy4e0V2WUf6ZXsYuKTzBksBu9ugZyDEzbhSoEKNOtEHODfn/m5HzShnCazB dFk3FU6ICmnGdwbaOicumejT+l9XkXdXZx3tvUnBkRODrtsJ8Z3w3H7+5g06Bp/MO39M IN4NolxbQfmAItlifdtYc9RlhdpIcIxqVZvAtoY75m7xeDdVwk2bx3OTqIfGLhK2vgAt KhXFDCRfqJeCtRU+6FTWjr0bWfPBdu7ovnIkvQa5DVQZr5qt7IckpQv8rs+VdEvsC1Pc iafA== X-Gm-Message-State: AOAM531VSZsF+Zh4GYKSHo2S7QsRLqOPj5evANjHInzB9KeLTtVbycjO XPCHiGPvLLH6BybLLi7wSDU= X-Google-Smtp-Source: ABdhPJwfFE1Okx71Js6IHRadfTJYlKRDeh+tPkSdb2+dq9wLCFYZ/j3/+hU+6FP7yjA5EuTR8UwbTg== X-Received: by 2002:a17:90a:c484:: with SMTP id j4mr11163356pjt.218.1625473242038; Mon, 05 Jul 2021 01:20:42 -0700 (PDT) Received: from localhost.localdomain ([156.146.35.76]) by smtp.gmail.com with ESMTPSA id y11sm12209986pfo.160.2021.07.05.01.20.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Jul 2021 01:20:41 -0700 (PDT) From: William Breathitt Gray To: jic23@kernel.org Cc: linux-stm32@st-md-mailman.stormreply.com, kernel@pengutronix.de, a.fatoum@pengutronix.de, kamel.bouhara@bootlin.com, gwendal@chromium.org, alexandre.belloni@bootlin.com, david@lechnology.com, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, syednwaris@gmail.com, patrick.havelange@essensium.com, fabrice.gasnier@st.com, mcoquelin.stm32@gmail.com, alexandre.torgue@st.com, o.rempel@pengutronix.de, jarkko.nikula@linux.intel.com, William Breathitt Gray Subject: [PATCH v12 15/17] counter: Implement events_queue_size sysfs attribute Date: Mon, 5 Jul 2021 17:19:03 +0900 Message-Id: X-Mailer: git-send-email 2.32.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org The events_queue_size sysfs attribute provides a way for users to dynamically configure the Counter events queue size for the Counter character device interface. The size is in number of struct counter_event data structures. The number of elements will be rounded-up to a power of 2 due to a requirement of the kfifo_alloc function called during reallocation of the queue. Cc: Oleksij Rempel Signed-off-by: William Breathitt Gray Reported-by: kernel test robot Reported-by: Dan Carpenter --- Documentation/ABI/testing/sysfs-bus-counter | 8 ++++ drivers/counter/counter-chrdev.c | 4 ++ drivers/counter/counter-sysfs.c | 44 +++++++++++++++++++++ include/linux/counter.h | 2 + 4 files changed, 58 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter index e0e99adb0ecc..84ebb1ed28ed 100644 --- a/Documentation/ABI/testing/sysfs-bus-counter +++ b/Documentation/ABI/testing/sysfs-bus-counter @@ -233,6 +233,14 @@ Description: shorter or equal to configured value are ignored. Value 0 means filter is disabled. +What: /sys/bus/counter/devices/counterX/events_queue_size +KernelVersion: 5.15 +Contact: linux-iio@vger.kernel.org +Description: + Size of the Counter events queue in number of struct + counter_event data structures. The number of elements will be + rounded-up to a power of 2. + What: /sys/bus/counter/devices/counterX/name KernelVersion: 5.2 Contact: linux-iio@vger.kernel.org diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c index 92805b1f65b8..13644c87d02a 100644 --- a/drivers/counter/counter-chrdev.c +++ b/drivers/counter/counter-chrdev.c @@ -323,6 +323,9 @@ static int counter_chrdev_open(struct inode *inode, struct file *filp) typeof(*counter), chrdev); + if (!mutex_trylock(&counter->chrdev_lock)) + return -EBUSY; + get_device(&counter->dev); filp->private_data = counter; @@ -339,6 +342,7 @@ static int counter_chrdev_release(struct inode *inode, struct file *filp) return err; put_device(&counter->dev); + mutex_unlock(&counter->chrdev_lock); return 0; } diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c index eb1505bfbd89..bf038eff4587 100644 --- a/drivers/counter/counter-sysfs.c +++ b/drivers/counter/counter-sysfs.c @@ -8,7 +8,9 @@ #include #include #include +#include #include +#include #include #include #include @@ -782,12 +784,48 @@ static int counter_num_counts_read(struct counter_device *counter, u8 *val) return 0; } +static int counter_events_queue_size_read(struct counter_device *counter, + u64 *val) +{ + *val = kfifo_size(&counter->events); + return 0; +} + +static int counter_events_queue_size_write(struct counter_device *counter, + u64 val) +{ + int err; + DECLARE_KFIFO_PTR(events, struct counter_event); + + /* Verify chrdev is not currently being used */ + if (!mutex_trylock(&counter->chrdev_lock)) + return -EBUSY; + + /* Allocate new events queue */ + err = kfifo_alloc(&events, val, GFP_ATOMIC); + if (err) + return err; + + /* Swap in new events queue */ + kfifo_free(&counter->events); + counter->events.kfifo = events.kfifo; + + mutex_unlock(&counter->chrdev_lock); + + return 0; +} + static struct counter_comp counter_num_signals_comp = COUNTER_COMP_DEVICE_U8("num_signals", counter_num_signals_read, NULL); static struct counter_comp counter_num_counts_comp = COUNTER_COMP_DEVICE_U8("num_counts", counter_num_counts_read, NULL); +static struct counter_comp counter_events_queue_size_comp = + COUNTER_COMP_DEVICE_U64("events_queue_size", + counter_events_queue_size_read, + counter_events_queue_size_write); + static int counter_sysfs_attr_add(struct counter_device *const counter, struct counter_attribute_group *group) { @@ -826,6 +864,12 @@ static int counter_sysfs_attr_add(struct counter_device *const counter, if (err < 0) return err; + /* Create num_counts attribute */ + err = counter_attr_create(dev, group, &counter_events_queue_size_comp, + scope, NULL); + if (err < 0) + return err; + /* Create an attribute for each extension */ for (i = 0; i < counter->num_ext; i++) { ext = counter->ext + i; diff --git a/include/linux/counter.h b/include/linux/counter.h index 3f0bbe4ff702..854fcaf49c32 100644 --- a/include/linux/counter.h +++ b/include/linux/counter.h @@ -289,6 +289,7 @@ struct counter_ops { * @priv: optional private data supplied by driver * @dev: internal device structure * @chrdev: internal character device structure + * @chrdev_lock: lock to limit chrdev to a single open at a time * @events_list: list of current watching Counter events * @events_list_lock: lock to protect Counter events list operations * @next_events_list: list of next watching Counter events @@ -314,6 +315,7 @@ struct counter_device { struct device dev; struct cdev chrdev; + struct mutex chrdev_lock; struct list_head events_list; spinlock_t events_list_lock; struct list_head next_events_list;