From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A112A47A6C; Tue, 14 May 2024 11:36:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715686561; cv=none; b=FQgWyIooSKD2xivmsUhpFkdR9/DehDgqjhIZiPK7I+0zCCgSK8de3+jqCApkOiXENmP0F7FmjcJrw5y/DY9e8GM29F6B3v6P+kt2qHRMe6r/8nt8jJ2J01svNub3vPLYvs4QC1n2Ih0KtGNehUwN7DxeMzLmkuotVrT94i2II7k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715686561; c=relaxed/simple; bh=jPEMMWKvI5mlpDk4f+uVqX3SHdg2E4dway9a8PcGSK0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WtgyoomOOVTUGSw9FaPZpsmoa+nR8v2K+acbdDh6ZiuzClAv+cfM7iQC+W6ctNvIuNEbWM39WBzGsG2jb4kHD80q8ADpJmIN5+TP5uVf9uGVn1c/tbPXTnh1dE43JJG0HukY24d8II1SinQnBMm6480knbIM43Z+xsWnRNC5kBg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ue9R/ytK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ue9R/ytK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1E4F4C2BD10; Tue, 14 May 2024 11:36:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1715686561; bh=jPEMMWKvI5mlpDk4f+uVqX3SHdg2E4dway9a8PcGSK0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ue9R/ytKZmBJc0tZDintmmbKPf1FlICRa727q4yNkN/vIWTdoy0DWzbA4GF53VpGJ 7y+x4ZR5eR/y/vQijJWbp2Yfn/Yq8kX0gC7378ZEbwiPkLzQj5UqNE/1MG4bcMZoas ufmnff1aniikDhB0eHlWhB8DuaJ+ZJhw/xocyUeQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kent Gibson , Andy Shevchenko , Bartosz Golaszewski , Sasha Levin Subject: [PATCH 6.1 179/236] gpiolib: cdev: relocate debounce_period_us from struct gpio_desc Date: Tue, 14 May 2024 12:19:01 +0200 Message-ID: <20240514101027.156140782@linuxfoundation.org> X-Mailer: git-send-email 2.45.0 In-Reply-To: <20240514101020.320785513@linuxfoundation.org> References: <20240514101020.320785513@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kent Gibson [ Upstream commit 9344e34e7992fec95ce6210d95ac01437dd327ab ] 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 Reviewed-by: Andy Shevchenko Signed-off-by: Bartosz Golaszewski Stable-dep-of: ee0166b637a5 ("gpiolib: cdev: fix uninitialised kfifo") Signed-off-by: Sasha Levin --- drivers/gpio/gpiolib-cdev.c | 165 +++++++++++++++++++++++++++++++----- 1 file changed, 142 insertions(+), 23 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index d2027212901fd..6ee1074d49152 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -5,6 +5,7 @@ #include #include #include +#include #include #include #include @@ -21,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -465,6 +467,7 @@ 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 @@ -477,6 +480,7 @@ 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 @@ -485,6 +489,7 @@ 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 -- @@ -518,6 +523,15 @@ 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 @@ -550,6 +564,17 @@ 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_has_supinfo(). + */ +static struct rb_root supinfo_tree = RB_ROOT; +/* covers supinfo_tree */ +static DEFINE_SPINLOCK(supinfo_lock); + /** * struct linereq - contains the state of a userspace line request * @gdev: the GPIO device the line request pertains to @@ -562,7 +587,8 @@ struct line { * this line request. Note that this is not used when @num_lines is 1, as * the line_seqno is then the same and is cheaper to calculate. * @config_mutex: mutex for serializing ioctl() calls to ensure consistency - * of configuration, particularly multi-step accesses to desc flags. + * of configuration, particularly multi-step accesses to desc flags and + * changes to supinfo status. * @lines: the lines held by this line request, with @num_lines elements. */ struct linereq { @@ -577,6 +603,103 @@ struct linereq { struct line 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) + return; + + 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_has_supinfo(struct line *line) +{ + return READ_ONCE(line->debounce_period_us); +} + +/* + * Checks line_has_supinfo() before and after the change to avoid unnecessary + * supinfo_tree access. + * Called indirectly by linereq_create() or linereq_set_config() so line + * is already protected from concurrent changes. + */ +static void line_set_debounce_period(struct line *line, + unsigned int debounce_period_us) +{ + bool was_suppl = line_has_supinfo(line); + + WRITE_ONCE(line->debounce_period_us, debounce_period_us); + + /* if supinfo status is unchanged then we're done */ + if (line_has_supinfo(line) == was_suppl) + return; + + /* supinfo status has changed, so update the tree */ + 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 | \ @@ -714,7 +837,7 @@ 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; @@ -855,7 +978,7 @@ 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; } @@ -937,7 +1060,7 @@ 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) @@ -1016,8 +1139,7 @@ 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() */ } @@ -1042,7 +1164,7 @@ 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 */ @@ -1084,12 +1206,12 @@ 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; } @@ -1566,13 +1688,18 @@ static ssize_t linereq_read(struct file *file, char __user *buf, static void linereq_free(struct linereq *lr) { + struct line *line; unsigned int i; 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_has_supinfo(line)) + supinfo_erase(line); + gpiod_free(line->desc); } kfifo_free(&lr->events); kfree(lr->label); @@ -2239,8 +2366,6 @@ 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); @@ -2307,14 +2432,6 @@ 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); } @@ -2420,6 +2537,7 @@ 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) @@ -2523,6 +2641,7 @@ 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) -- 2.43.0