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[60.241.235.125]) by smtp.gmail.com with ESMTPSA id fk16-20020a056a003a9000b006d26920a11dsm1437987pfb.0.2023.12.14.18.38.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Dec 2023 18:38:36 -0800 (PST) From: Kent Gibson To: linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, brgl@bgdev.pl, linus.walleij@linaro.org, andy@kernel.org Cc: Kent Gibson Subject: [PATCH v3 1/5] gpiolib: cdev: relocate debounce_period_us from struct gpio_desc Date: Fri, 15 Dec 2023 10:38:01 +0800 Message-Id: <20231215023805.63289-2-warthog618@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231215023805.63289-1-warthog618@gmail.com> References: <20231215023805.63289-1-warthog618@gmail.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Store the debounce period for a requested line locally, rather than in the debounce_period_us field in the gpiolib struct gpio_desc. Add a global tree of lines containing supplemental line information to make the debounce period available to be reported by the GPIO_V2_GET_LINEINFO_IOCTL and the line change notifier. Signed-off-by: Kent Gibson --- drivers/gpio/gpiolib-cdev.c | 152 ++++++++++++++++++++++++++++++------ 1 file changed, 130 insertions(+), 22 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 02ffda6c1e51..5ba900e5461a 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -461,6 +462,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) /** * struct line - contains the state of a requested line + * @node: to store the object in supinfo_tree if supplemental * @desc: the GPIO descriptor for this line. * @req: the corresponding line request * @irq: the interrupt triggered in response to events on this GPIO @@ -473,6 +475,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) * @line_seqno: the seqno for the current edge event in the sequence of * events for this line. * @work: the worker that implements software debouncing + * @debounce_period_us: the debounce period in microseconds * @sw_debounced: flag indicating if the software debouncer is active * @level: the current debounced physical level of the line * @hdesc: the Hardware Timestamp Engine (HTE) descriptor @@ -481,6 +484,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip) * @last_seqno: the last sequence number before debounce period expires */ struct line { + struct rb_node node; struct gpio_desc *desc; /* * -- edge detector specific fields -- @@ -514,6 +518,15 @@ struct line { * -- debouncer specific fields -- */ struct delayed_work work; + /* + * debounce_period_us is accessed by debounce_irq_handler() and + * process_hw_ts() which are disabled when modified by + * debounce_setup(), edge_detector_setup() or edge_detector_stop() + * or can live with a stale version when updated by + * edge_detector_update(). + * The modifying functions are themselves mutually exclusive. + */ + unsigned int debounce_period_us; /* * sw_debounce is accessed by linereq_set_config(), which is the * only setter, and linereq_get_values(), which can live with a @@ -546,6 +559,17 @@ struct line { #endif /* CONFIG_HTE */ }; +/* + * a rbtree of the struct lines containing supplemental info. + * Used to populate gpio_v2_line_info with cdev specific fields not contained + * in the struct gpio_desc. + * A line is determined to contain supplemental information by + * line_is_supplemental(). + */ +static struct rb_root supinfo_tree = RB_ROOT; +/* covers supinfo_tree */ +DEFINE_SPINLOCK(supinfo_lock); + /** * struct linereq - contains the state of a userspace line request * @gdev: the GPIO device the line request pertains to @@ -575,6 +599,94 @@ struct linereq { struct line lines[] __counted_by(num_lines); }; +static void supinfo_insert(struct line *line) +{ + struct rb_node **new = &(supinfo_tree.rb_node), *parent = NULL; + struct line *entry; + + guard(spinlock)(&supinfo_lock); + + while (*new) { + entry = container_of(*new, struct line, node); + + parent = *new; + if (line->desc < entry->desc) { + new = &((*new)->rb_left); + } else if (line->desc > entry->desc) { + new = &((*new)->rb_right); + } else { + /* this should never happen */ + WARN(1, "duplicate line inserted"); + return; + } + } + + rb_link_node(&line->node, parent, new); + rb_insert_color(&line->node, &supinfo_tree); +} + +static void supinfo_erase(struct line *line) +{ + guard(spinlock)(&supinfo_lock); + + rb_erase(&line->node, &supinfo_tree); +} + +static struct line *supinfo_find(struct gpio_desc *desc) +{ + struct rb_node *node = supinfo_tree.rb_node; + struct line *line; + + while (node) { + line = container_of(node, struct line, node); + if (desc < line->desc) + node = node->rb_left; + else if (desc > line->desc) + node = node->rb_right; + else + return line; + } + return NULL; +} + +static void supinfo_to_lineinfo(struct gpio_desc *desc, + struct gpio_v2_line_info *info) +{ + struct gpio_v2_line_attribute *attr; + struct line *line; + + guard(spinlock)(&supinfo_lock); + + line = supinfo_find(desc); + if (line) { + attr = &info->attrs[info->num_attrs]; + attr->id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; + attr->debounce_period_us = READ_ONCE(line->debounce_period_us); + info->num_attrs++; + } +} + +static inline bool line_is_supplemental(struct line *line) +{ + return READ_ONCE(line->debounce_period_us); +} + +static void line_set_debounce_period(struct line *line, + unsigned int debounce_period_us) +{ + bool was_suppl = line_is_supplemental(line); + + WRITE_ONCE(line->debounce_period_us, debounce_period_us); + + if (line_is_supplemental(line) == was_suppl) + return; + + if (was_suppl) + supinfo_erase(line); + else + supinfo_insert(line); +} + #define GPIO_V2_LINE_BIAS_FLAGS \ (GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \ GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \ @@ -723,7 +835,7 @@ static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p) line->total_discard_seq++; line->last_seqno = ts->seq; mod_delayed_work(system_wq, &line->work, - usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); + usecs_to_jiffies(READ_ONCE(line->debounce_period_us))); } else { if (unlikely(ts->seq < line->line_seqno)) return HTE_CB_HANDLED; @@ -864,7 +976,7 @@ static irqreturn_t debounce_irq_handler(int irq, void *p) struct line *line = p; mod_delayed_work(system_wq, &line->work, - usecs_to_jiffies(READ_ONCE(line->desc->debounce_period_us))); + usecs_to_jiffies(READ_ONCE(line->debounce_period_us))); return IRQ_HANDLED; } @@ -946,7 +1058,7 @@ static int debounce_setup(struct line *line, unsigned int debounce_period_us) /* try hardware */ ret = gpiod_set_debounce(line->desc, debounce_period_us); if (!ret) { - WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); + line_set_debounce_period(line, debounce_period_us); return ret; } if (ret != -ENOTSUPP) @@ -1025,8 +1137,7 @@ static void edge_detector_stop(struct line *line) cancel_delayed_work_sync(&line->work); WRITE_ONCE(line->sw_debounced, 0); WRITE_ONCE(line->edflags, 0); - if (line->desc) - WRITE_ONCE(line->desc->debounce_period_us, 0); + line_set_debounce_period(line, 0); /* do not change line->level - see comment in debounced_value() */ } @@ -1051,7 +1162,7 @@ static int edge_detector_setup(struct line *line, ret = debounce_setup(line, debounce_period_us); if (ret) return ret; - WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); + line_set_debounce_period(line, debounce_period_us); } /* detection disabled or sw debouncer will provide edge detection */ @@ -1093,12 +1204,12 @@ static int edge_detector_update(struct line *line, gpio_v2_line_config_debounce_period(lc, line_idx); if ((active_edflags == edflags) && - (READ_ONCE(line->desc->debounce_period_us) == debounce_period_us)) + (READ_ONCE(line->debounce_period_us) == debounce_period_us)) return 0; /* sw debounced and still will be...*/ if (debounce_period_us && READ_ONCE(line->sw_debounced)) { - WRITE_ONCE(line->desc->debounce_period_us, debounce_period_us); + line_set_debounce_period(line, debounce_period_us); return 0; } @@ -1573,6 +1684,7 @@ static ssize_t linereq_read(struct file *file, char __user *buf, static void linereq_free(struct linereq *lr) { + struct line *line; unsigned int i; if (lr->device_unregistered_nb.notifier_call) @@ -1580,10 +1692,14 @@ static void linereq_free(struct linereq *lr) &lr->device_unregistered_nb); for (i = 0; i < lr->num_lines; i++) { - if (lr->lines[i].desc) { - edge_detector_stop(&lr->lines[i]); - gpiod_free(lr->lines[i].desc); - } + line = &lr->lines[i]; + if (!line->desc) + continue; + + edge_detector_stop(line); + if (line_is_supplemental(line)) + supinfo_erase(line); + gpiod_free(line->desc); } kfifo_free(&lr->events); kfree(lr->label); @@ -2274,8 +2390,6 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, struct gpio_chip *gc = desc->gdev->chip; bool ok_for_pinctrl; unsigned long flags; - u32 debounce_period_us; - unsigned int num_attrs = 0; memset(info, 0, sizeof(*info)); info->offset = gpio_chip_hwgpio(desc); @@ -2341,14 +2455,6 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags)) info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; - debounce_period_us = READ_ONCE(desc->debounce_period_us); - if (debounce_period_us) { - info->attrs[num_attrs].id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE; - info->attrs[num_attrs].debounce_period_us = debounce_period_us; - num_attrs++; - } - info->num_attrs = num_attrs; - spin_unlock_irqrestore(&gpio_lock, flags); } @@ -2455,6 +2561,7 @@ static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip, return -EBUSY; } gpio_desc_to_lineinfo(desc, &lineinfo); + supinfo_to_lineinfo(desc, &lineinfo); if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) { if (watch) @@ -2545,6 +2652,7 @@ static int lineinfo_changed_notify(struct notifier_block *nb, chg.event_type = action; chg.timestamp_ns = ktime_get_ns(); gpio_desc_to_lineinfo(desc, &chg.info); + supinfo_to_lineinfo(desc, &chg.info); ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock); if (ret) From patchwork Fri Dec 15 02:38:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kent Gibson X-Patchwork-Id: 755747 Received: from mail-pg1-f173.google.com (mail-pg1-f173.google.com [209.85.215.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 157778BF1; Fri, 15 Dec 2023 02:38:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="CZ2f8aLx" Received: by mail-pg1-f173.google.com with SMTP id 41be03b00d2f7-5c6839373f8so113365a12.0; 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[60.241.235.125]) by smtp.gmail.com with ESMTPSA id fk16-20020a056a003a9000b006d26920a11dsm1437987pfb.0.2023.12.14.18.38.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Dec 2023 18:38:42 -0800 (PST) From: Kent Gibson To: linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, brgl@bgdev.pl, linus.walleij@linaro.org, andy@kernel.org Cc: Kent Gibson Subject: [PATCH v3 2/5] gpiolib: remove debounce_period_us from struct gpio_desc Date: Fri, 15 Dec 2023 10:38:02 +0800 Message-Id: <20231215023805.63289-3-warthog618@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231215023805.63289-1-warthog618@gmail.com> References: <20231215023805.63289-1-warthog618@gmail.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 cdev is the only user of the debounce_period_us field in struct gpio_desc, and it no longer uses it, so remove it. Signed-off-by: Kent Gibson --- drivers/gpio/gpiolib.c | 3 --- drivers/gpio/gpiolib.h | 5 ----- 2 files changed, 8 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 4e190be75dc2..ca2216621619 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2344,9 +2344,6 @@ static bool gpiod_free_commit(struct gpio_desc *desc) clear_bit(FLAG_IS_HOGGED, &desc->flags); #ifdef CONFIG_OF_DYNAMIC desc->hog = NULL; -#endif -#ifdef CONFIG_GPIO_CDEV - WRITE_ONCE(desc->debounce_period_us, 0); #endif ret = true; } diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 3ccacf3c1288..a4a2520b5f31 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -147,7 +147,6 @@ void gpiod_line_state_notify(struct gpio_desc *desc, unsigned long action); * @label: Name of the consumer * @name: Line name * @hog: Pointer to the device node that hogs this line (if any) - * @debounce_period_us: Debounce period in microseconds * * These are obtained using gpiod_get() and are preferable to the old * integer-based handles. @@ -185,10 +184,6 @@ struct gpio_desc { #ifdef CONFIG_OF_DYNAMIC struct device_node *hog; #endif -#ifdef CONFIG_GPIO_CDEV - /* debounce period in microseconds */ - unsigned int debounce_period_us; -#endif }; #define gpiod_not_found(desc) (IS_ERR(desc) && PTR_ERR(desc) == -ENOENT) From patchwork Fri Dec 15 02:38:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kent Gibson X-Patchwork-Id: 754675 Received: from mail-oi1-f174.google.com (mail-oi1-f174.google.com [209.85.167.174]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CBC7D271; Fri, 15 Dec 2023 02:39:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ieCk6gG9" Received: by mail-oi1-f174.google.com with SMTP id 5614622812f47-3b9ef61b6b8so194947b6e.3; Thu, 14 Dec 2023 18:39:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702607964; x=1703212764; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=CtO2jY+EJP8Yvc8VKZdfYbcqASBoJOxP1iWf7Ww080E=; b=ieCk6gG9OZ3zhBPcrphnGM4Zy31QEtol5Znhd8nXoBvILsf7aenHXe2gmoJX8B52Ha mlU9bLeeU499mQbATPYQtHDbtX0uyizU5J67KwAvOgOmSIQ4D8JeQLPxgiyDcgNKYHTn ichXppg1/BCx7dKJNrLTCsJK1YpEB9k4l3BDQnovo9OCKwlvBQuYeSmLKpLEBzSTNhQb y2ZKDbztadPCHk9W+bw5Dd5ivz3+OvfvMkhhOH4Qv8IaX1rhFYWMiqBi1D6JtJdI+58i Y/ijsgfqwByBRSBFmXfu8y+4dMqLLAN1SnG1cOf0RWE/NnZtOaA7XmPlu0kRBT8gSaai +GfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702607964; x=1703212764; 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=CtO2jY+EJP8Yvc8VKZdfYbcqASBoJOxP1iWf7Ww080E=; b=UuEnNACyOSfVsBN/oBcFiLz1FXOeZ/MM0J0v0/wIV4o3nqEbGd91ts0UDUF9DCXACa C5j/w+TA0oE3RNgPa+HJ1s2qCoJQvXXFPYflOMxrz1tZlmVl3v+Q19THtifap5oLsT5/ 7ETw0+obwpMnFVNNlgNbv/4NUoE+GKFNI4z76GP9f7HBKopwdv62haD8dM2xPdApckiv Wm3VgZH7MJOOAM5Bq3FaEO0fCcEXISJ+7yJNX4gzIu64tcwLju4en4oNDxnjajbDa8Hb UskjtRVrGMy8V8oPtbdr1dDA3PJGeQ46TV6IZ2MqJUG6HXTUNfwBXeBv2blamMGbCzQx 4FKA== X-Gm-Message-State: AOJu0YzndLHzrsSrj1Ew0Okia/OFACXTB8GXV7G4ab1qScDQxtO+M2rr O6DBRTst9z5iXMmQ/YjnohfhZq6lf3o= X-Google-Smtp-Source: AGHT+IGlWzYrWM676OibeACK5orQ7R+AmQhDbYKx4mELUlDz4VX1TgfrhcqgtIS/bYb8y4f2jQUxJw== X-Received: by 2002:a05:6808:ecb:b0:3b9:d903:9fa9 with SMTP id q11-20020a0568080ecb00b003b9d9039fa9mr13502871oiv.105.1702607964084; Thu, 14 Dec 2023 18:39:24 -0800 (PST) Received: from rigel.home.arpa (60-241-235-125.tpgi.com.au. [60.241.235.125]) by smtp.gmail.com with ESMTPSA id fk16-20020a056a003a9000b006d26920a11dsm1437987pfb.0.2023.12.14.18.39.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Dec 2023 18:39:23 -0800 (PST) From: Kent Gibson To: linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, brgl@bgdev.pl, linus.walleij@linaro.org, andy@kernel.org Cc: Kent Gibson Subject: [PATCH v3 3/5] gpiolib: cdev: reduce locking in gpio_desc_to_lineinfo() Date: Fri, 15 Dec 2023 10:38:03 +0800 Message-Id: <20231215023805.63289-4-warthog618@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231215023805.63289-1-warthog618@gmail.com> References: <20231215023805.63289-1-warthog618@gmail.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Reduce the time holding the gpio_lock by snapshotting the desc flags, rather than testing them individually while holding the lock. Accept that the calculation of the used field is inherently racy, and only check the availability of the line from pinctrl if other checks pass, so avoiding the check for lines that are otherwise in use. Signed-off-by: Kent Gibson --- drivers/gpio/gpiolib-cdev.c | 74 ++++++++++++++++++------------------- 1 file changed, 36 insertions(+), 38 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 5ba900e5461a..c140bcd63361 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -2388,74 +2388,72 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, struct gpio_v2_line_info *info) { struct gpio_chip *gc = desc->gdev->chip; - bool ok_for_pinctrl; - unsigned long flags; + unsigned long dflags; memset(info, 0, sizeof(*info)); info->offset = gpio_chip_hwgpio(desc); - /* - * This function takes a mutex so we must check this before taking - * the spinlock. - * - * FIXME: find a non-racy way to retrieve this information. Maybe a - * lock common to both frameworks? - */ - ok_for_pinctrl = pinctrl_gpio_can_use_line(gc, info->offset); + scoped_guard(spinlock_irqsave, &gpio_lock) { + if (desc->name) + strscpy(info->name, desc->name, sizeof(info->name)); - spin_lock_irqsave(&gpio_lock, flags); + if (desc->label) + strscpy(info->consumer, desc->label, + sizeof(info->consumer)); - if (desc->name) - strscpy(info->name, desc->name, sizeof(info->name)); - - if (desc->label) - strscpy(info->consumer, desc->label, sizeof(info->consumer)); + dflags = READ_ONCE(desc->flags); + } /* - * Userspace only need to know that the kernel is using this GPIO so - * it can't use it. + * Userspace only need know that the kernel is using this GPIO so it + * can't use it. + * The calculation of the used flag is slightly racy, as it may read + * desc, gc and pinctrl state without a lock covering all three at + * once. Worst case if the line is in transition and the calculation + * is inconsistent then it looks to the user like they performed the + * read on the other side of the transition - but that can always + * happen. + * The definitive test that a line is available to userspace is to + * request it. */ - info->flags = 0; - if (test_bit(FLAG_REQUESTED, &desc->flags) || - test_bit(FLAG_IS_HOGGED, &desc->flags) || - test_bit(FLAG_USED_AS_IRQ, &desc->flags) || - test_bit(FLAG_EXPORT, &desc->flags) || - test_bit(FLAG_SYSFS, &desc->flags) || + if (test_bit(FLAG_REQUESTED, &dflags) || + test_bit(FLAG_IS_HOGGED, &dflags) || + test_bit(FLAG_USED_AS_IRQ, &dflags) || + test_bit(FLAG_EXPORT, &dflags) || + test_bit(FLAG_SYSFS, &dflags) || !gpiochip_line_is_valid(gc, info->offset) || - !ok_for_pinctrl) + !pinctrl_gpio_can_use_line(gc, info->offset)) info->flags |= GPIO_V2_LINE_FLAG_USED; - if (test_bit(FLAG_IS_OUT, &desc->flags)) + if (test_bit(FLAG_IS_OUT, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_OUTPUT; else info->flags |= GPIO_V2_LINE_FLAG_INPUT; - if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) + if (test_bit(FLAG_ACTIVE_LOW, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW; - if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) + if (test_bit(FLAG_OPEN_DRAIN, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN; - if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) + if (test_bit(FLAG_OPEN_SOURCE, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE; - if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) + if (test_bit(FLAG_BIAS_DISABLE, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED; - if (test_bit(FLAG_PULL_DOWN, &desc->flags)) + if (test_bit(FLAG_PULL_DOWN, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN; - if (test_bit(FLAG_PULL_UP, &desc->flags)) + if (test_bit(FLAG_PULL_UP, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP; - if (test_bit(FLAG_EDGE_RISING, &desc->flags)) + if (test_bit(FLAG_EDGE_RISING, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING; - if (test_bit(FLAG_EDGE_FALLING, &desc->flags)) + if (test_bit(FLAG_EDGE_FALLING, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING; - if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &desc->flags)) + if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME; - else if (test_bit(FLAG_EVENT_CLOCK_HTE, &desc->flags)) + else if (test_bit(FLAG_EVENT_CLOCK_HTE, &dflags)) info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE; - - spin_unlock_irqrestore(&gpio_lock, flags); } struct gpio_chardev_data { From patchwork Fri Dec 15 02:38:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kent Gibson X-Patchwork-Id: 755746 Received: from mail-oi1-f173.google.com (mail-oi1-f173.google.com [209.85.167.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3073AC8FD; Fri, 15 Dec 2023 02:39:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; 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[60.241.235.125]) by smtp.gmail.com with ESMTPSA id fk16-20020a056a003a9000b006d26920a11dsm1437987pfb.0.2023.12.14.18.39.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Dec 2023 18:39:38 -0800 (PST) From: Kent Gibson To: linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, brgl@bgdev.pl, linus.walleij@linaro.org, andy@kernel.org Cc: Kent Gibson Subject: [PATCH v3 4/5] gpiolib: cdev: fully adopt guard() and scoped_guard() Date: Fri, 15 Dec 2023 10:38:04 +0800 Message-Id: <20231215023805.63289-5-warthog618@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231215023805.63289-1-warthog618@gmail.com> References: <20231215023805.63289-1-warthog618@gmail.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Use guard() or scoped_guard() for critical sections rather than discrete lock/unlock pairs. Signed-off-by: Kent Gibson --- drivers/gpio/gpiolib-cdev.c | 143 ++++++++++++++---------------------- 1 file changed, 57 insertions(+), 86 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index c140bcd63361..b956664f8649 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -737,13 +737,13 @@ static void linereq_put_event(struct linereq *lr, { bool overflow = false; - spin_lock(&lr->wait.lock); - if (kfifo_is_full(&lr->events)) { - overflow = true; - kfifo_skip(&lr->events); + scoped_guard(spinlock, &lr->wait.lock) { + if (kfifo_is_full(&lr->events)) { + overflow = true; + kfifo_skip(&lr->events); + } + kfifo_in(&lr->events, le, 1); } - kfifo_in(&lr->events, le, 1); - spin_unlock(&lr->wait.lock); if (!overflow) wake_up_poll(&lr->wait, EPOLLIN); else @@ -1476,18 +1476,13 @@ static long linereq_set_values_unlocked(struct linereq *lr, static long linereq_set_values(struct linereq *lr, void __user *ip) { struct gpio_v2_line_values lv; - int ret; if (copy_from_user(&lv, ip, sizeof(lv))) return -EFAULT; - mutex_lock(&lr->config_mutex); - - ret = linereq_set_values_unlocked(lr, &lv); - - mutex_unlock(&lr->config_mutex); + guard(mutex)(&lr->config_mutex); - return ret; + return linereq_set_values_unlocked(lr, &lv); } static long linereq_set_config_unlocked(struct linereq *lr, @@ -1545,13 +1540,9 @@ static long linereq_set_config(struct linereq *lr, void __user *ip) if (ret) return ret; - mutex_lock(&lr->config_mutex); - - ret = linereq_set_config_unlocked(lr, &lc); + guard(mutex)(&lr->config_mutex); - mutex_unlock(&lr->config_mutex); - - return ret; + return linereq_set_config_unlocked(lr, &lc); } static long linereq_ioctl_unlocked(struct file *file, unsigned int cmd, @@ -1633,28 +1624,22 @@ static ssize_t linereq_read_unlocked(struct file *file, char __user *buf, return -EINVAL; do { - spin_lock(&lr->wait.lock); - if (kfifo_is_empty(&lr->events)) { - if (bytes_read) { - spin_unlock(&lr->wait.lock); - return bytes_read; + scoped_guard(spinlock, &lr->wait.lock) { + if (kfifo_is_empty(&lr->events)) { + if (bytes_read) + return bytes_read; + + if (file->f_flags & O_NONBLOCK) + return -EAGAIN; + + ret = wait_event_interruptible_locked(lr->wait, + !kfifo_is_empty(&lr->events)); + if (ret) + return ret; } - if (file->f_flags & O_NONBLOCK) { - spin_unlock(&lr->wait.lock); - return -EAGAIN; - } - - ret = wait_event_interruptible_locked(lr->wait, - !kfifo_is_empty(&lr->events)); - if (ret) { - spin_unlock(&lr->wait.lock); - return ret; - } + ret = kfifo_out(&lr->events, &le, 1); } - - ret = kfifo_out(&lr->events, &le, 1); - spin_unlock(&lr->wait.lock); if (ret != 1) { /* * This should never happen - we were holding the @@ -2004,28 +1989,22 @@ static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf, return -EINVAL; do { - spin_lock(&le->wait.lock); - if (kfifo_is_empty(&le->events)) { - if (bytes_read) { - spin_unlock(&le->wait.lock); - return bytes_read; - } - - if (file->f_flags & O_NONBLOCK) { - spin_unlock(&le->wait.lock); - return -EAGAIN; + scoped_guard(spinlock, &le->wait.lock) { + if (kfifo_is_empty(&le->events)) { + if (bytes_read) + return bytes_read; + + if (file->f_flags & O_NONBLOCK) + return -EAGAIN; + + ret = wait_event_interruptible_locked(le->wait, + !kfifo_is_empty(&le->events)); + if (ret) + return ret; } - ret = wait_event_interruptible_locked(le->wait, - !kfifo_is_empty(&le->events)); - if (ret) { - spin_unlock(&le->wait.lock); - return ret; - } + ret = kfifo_out(&le->events, &ge, 1); } - - ret = kfifo_out(&le->events, &ge, 1); - spin_unlock(&le->wait.lock); if (ret != 1) { /* * This should never happen - we were holding the lock @@ -2719,38 +2698,30 @@ static ssize_t lineinfo_watch_read_unlocked(struct file *file, char __user *buf, #endif do { - spin_lock(&cdev->wait.lock); - if (kfifo_is_empty(&cdev->events)) { - if (bytes_read) { - spin_unlock(&cdev->wait.lock); - return bytes_read; - } - - if (file->f_flags & O_NONBLOCK) { - spin_unlock(&cdev->wait.lock); - return -EAGAIN; - } - - ret = wait_event_interruptible_locked(cdev->wait, - !kfifo_is_empty(&cdev->events)); - if (ret) { - spin_unlock(&cdev->wait.lock); - return ret; + scoped_guard(spinlock, &cdev->wait.lock) { + if (kfifo_is_empty(&cdev->events)) { + if (bytes_read) + return bytes_read; + + if (file->f_flags & O_NONBLOCK) + return -EAGAIN; + + ret = wait_event_interruptible_locked(cdev->wait, + !kfifo_is_empty(&cdev->events)); + if (ret) + return ret; } - } #ifdef CONFIG_GPIO_CDEV_V1 - /* must be after kfifo check so watch_abi_version is set */ - if (atomic_read(&cdev->watch_abi_version) == 2) - event_size = sizeof(struct gpio_v2_line_info_changed); - else - event_size = sizeof(struct gpioline_info_changed); - if (count < event_size) { - spin_unlock(&cdev->wait.lock); - return -EINVAL; - } + /* must be after kfifo check so watch_abi_version is set */ + if (atomic_read(&cdev->watch_abi_version) == 2) + event_size = sizeof(struct gpio_v2_line_info_changed); + else + event_size = sizeof(struct gpioline_info_changed); + if (count < event_size) + return -EINVAL; #endif - ret = kfifo_out(&cdev->events, &event, 1); 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[60.241.235.125]) by smtp.gmail.com with ESMTPSA id fk16-20020a056a003a9000b006d26920a11dsm1437987pfb.0.2023.12.14.18.39.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Dec 2023 18:39:48 -0800 (PST) From: Kent Gibson To: linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, brgl@bgdev.pl, linus.walleij@linaro.org, andy@kernel.org Cc: Kent Gibson Subject: [PATCH v3 5/5] gpiolib: cdev: improve documentation of get/set values Date: Fri, 15 Dec 2023 10:38:05 +0800 Message-Id: <20231215023805.63289-6-warthog618@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231215023805.63289-1-warthog618@gmail.com> References: <20231215023805.63289-1-warthog618@gmail.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add documentation of the algorithm used to perform scatter/gather of the requested lines and values in linereq_get_values() and linereq_set_values_unlocked() to improve maintainability. Signed-off-by: Kent Gibson --- drivers/gpio/gpiolib-cdev.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index b956664f8649..37794de691f3 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -1383,9 +1383,18 @@ static long linereq_get_values(struct linereq *lr, void __user *ip) if (copy_from_user(&lv, ip, sizeof(lv))) return -EFAULT; + /* + * gpiod_get_array_value_complex() requires compacted desc and val + * arrays, rather than the sparse ones in lv. + * Calculation of num_get and construction of the desc array is + * optimized to avoid allocation for the desc array for the common + * num_get == 1 case. + */ + /* scan requested lines to calculate the subset to get */ for (num_get = 0, i = 0; i < lr->num_lines; i++) { if (lv.mask & BIT_ULL(i)) { num_get++; + /* capture desc for the num_get == 1 case */ descs = &lr->lines[i].desc; } } @@ -1394,6 +1403,7 @@ static long linereq_get_values(struct linereq *lr, void __user *ip) return -EINVAL; if (num_get != 1) { + /* build compacted desc array */ descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL); if (!descs) return -ENOMEM; @@ -1414,6 +1424,7 @@ static long linereq_get_values(struct linereq *lr, void __user *ip) lv.bits = 0; for (didx = 0, i = 0; i < lr->num_lines; i++) { + /* unpack compacted vals for the response */ if (lv.mask & BIT_ULL(i)) { if (lr->lines[i].sw_debounced) val = debounced_value(&lr->lines[i]); @@ -1439,14 +1450,25 @@ static long linereq_set_values_unlocked(struct linereq *lr, unsigned int i, didx, num_set; int ret; + /* + * gpiod_set_array_value_complex() requires compacted desc and val + * arrays, rather than the sparse ones in lv. + * Calculation of num_set and construction of the descs and vals arrays + * is optimized to minimize scanning the lv->mask, and to avoid + * allocation for the desc array for the common num_set == 1 case. + */ bitmap_zero(vals, GPIO_V2_LINES_MAX); + /* scan requested lines to determine the subset to be set */ for (num_set = 0, i = 0; i < lr->num_lines; i++) { if (lv->mask & BIT_ULL(i)) { + /* setting inputs is not allowed */ if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags)) return -EPERM; + /* add to compacted values */ if (lv->bits & BIT_ULL(i)) __set_bit(num_set, vals); num_set++; + /* capture desc for the num_set == 1 case */ descs = &lr->lines[i].desc; } } @@ -1454,7 +1476,7 @@ static long linereq_set_values_unlocked(struct linereq *lr, return -EINVAL; if (num_set != 1) { - /* build compacted desc array and values */ + /* build compacted desc array */ descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL); if (!descs) return -ENOMEM;