From patchwork Thu Oct 3 17:34:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matteo Martelli X-Patchwork-Id: 13821306 Received: from mail-wm1-f45.google.com (mail-wm1-f45.google.com [209.85.128.45]) (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 9583C1AAE37; Thu, 3 Oct 2024 17:34:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.45 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727976886; cv=none; b=urChykO8Len1hvmyuUJBJAHHImbHBVbQu2njr/81XZikeQpdV1uOAISUa9BzZQA59oA4qVrgoshRfCdruEEXy7kqoPPRV9yJc9g1c+f3uPPEMrjTCFF8K+VlKpDWB4wg0+IXejk7khESTpM+7kUwEi9ApSsrfazzSYZfNYBgPyo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727976886; c=relaxed/simple; bh=cNg176BYetOGo2MpF+NBbDgUNyJwivGqccecDk2ywTU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=S6C0B0VvwqfBTdCJo6x1RbNJrntNy6KAJlEDrGe2DoHSTK5u12JFocXrmjaeb0ZA7gfGQiVe4ls4nQh6qjt71QzYDXP5TGYf+2YUmrTdI6McTG/1yCKnI/XjDw07aDjd50OFNgrn6QoebmTNibfKfa8a4yOFArHOvnvQn2FeS5U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=IaRETnWh; arc=none smtp.client-ip=209.85.128.45 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="IaRETnWh" Received: by mail-wm1-f45.google.com with SMTP id 5b1f17b1804b1-42cd74c0d16so12261635e9.1; Thu, 03 Oct 2024 10:34:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1727976883; x=1728581683; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=gYEu7vJAEzzRAf4hNdfGGtBas1po8e0YLUji+g4IAZE=; b=IaRETnWh+BMUXZcCFdAbtwdPtgEBswwTEwqU/DMuGFywJNhRduJdEBmdIMFgceTICg iqDHC8M1UqfOf7uaJ5ZCZ++sYZkGEfzgOnQI3iV+Te7+pT4Z31MF3m6C3TjHUc7WFvTv lAvO1pRMGu5+rA7KqePfm0GZzF8V6Zd0dTu3mpYYXaBdPGre4uZ+L0m2/7bda0daSC71 RfGXd4EU9Yi1kmvDzU3WVPxr5MVFyMyrkud4DC4N6LObZjq9PX1A75yniK/BFwcYGzJW srGXu8PuGGPji49dxopXMZi3zAfxWYkSSrun2mmC+IQg66ydsDCKJYPr3dlfmeqHba+l HufA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727976883; x=1728581683; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=gYEu7vJAEzzRAf4hNdfGGtBas1po8e0YLUji+g4IAZE=; b=eBvYTXQJI88TDI4qgOzEV5+nR7CP2HnzPhwGPlzCp8vUaYwNxgU1e2kB+uS84RI6gJ j8u6FAuDCh5opBzHYmo4RCn0fQXVw4cShv+lrl8VautlHPOVD+ChCNJTB6PhdYdjLNDZ SnqPrGIsk/euY3G/v6qIWBONJcy7xwP+5Zs6AieARdZ+5g0mARsdFxric30o+lZCW8ig et0dPJB3fH0h2cqONxEheU9Y0kAjCzrSk5JT6/5UzEN+DQVooAq8WfW0Mc11Vp3EYcVy 5XRMBKz5OHH8wpFTgIoia7gmwF+FiYYZY3gzPb+WXVWuORW0j+99bj1i9y+TpbKp7nTg UhKw== X-Forwarded-Encrypted: i=1; AJvYcCUz39CMTNXxEfIFHBFbgKhegTklAF3oXGKiipvQRRnEVyvCCRclO6WS3yvi6swxLPjbCKf5erhCu+tSHQ==@vger.kernel.org, AJvYcCWtk6tbr+shKXGBuJgpO8ely0TcdEaKm7ZkJK1ztx0eK/JZGwYflPQGOin7ko6L51ChkDj/ykZBycI=@vger.kernel.org, AJvYcCXEQM5ODlbtpFJvpN5YzF2p0xuxqxQkbCBdvctz1jKB3Cqut8/YJT6F6apbjZnMxtjbR5PoXJ2PtuIlEls=@vger.kernel.org X-Gm-Message-State: AOJu0Yy7HS3CdfJ2HUkZQfJH6jGpVp8yDSTbn/nKwQ+68/d4emWpdX1P 9R/ouz/eMlPMXsmRPusnttxSAa3S/EFYw/aXJb+oED8oPWh+Q6tx X-Google-Smtp-Source: AGHT+IHTPFOFNPN3BeckBHKcogONqJyh8WuQeJEfQQzsuoj40NUYhsA6Ja/Wd7KXoljDjmnGp5wiHA== X-Received: by 2002:a05:600c:1551:b0:42c:ac9f:b528 with SMTP id 5b1f17b1804b1-42f778f5ba5mr51635555e9.35.1727976882600; Thu, 03 Oct 2024 10:34:42 -0700 (PDT) Received: from localhost (host-79-19-52-27.retail.telecomitalia.it. [79.19.52.27]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-42f79c67c5csm50718505e9.0.2024.10.03.10.34.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Oct 2024 10:34:41 -0700 (PDT) From: Matteo Martelli Date: Thu, 03 Oct 2024 19:34:07 +0200 Subject: [PATCH 2/7] iio: pac1921: use read_avail+release APIs instead of custom ext_info Precedence: bulk X-Mailing-List: linux-mips@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20241003-iio-read-avail-release-v1-2-c70cc7d9c2e0@gmail.com> References: <20241003-iio-read-avail-release-v1-0-c70cc7d9c2e0@gmail.com> In-Reply-To: <20241003-iio-read-avail-release-v1-0-c70cc7d9c2e0@gmail.com> To: Jonathan Cameron , Lars-Peter Clausen , Michael Hennerich , Alisa-Dariana Roman , Christian Eggers , Peter Rosin , Paul Cercueil , Sebastian Reichel Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-pm@vger.kernel.org, Matteo Martelli X-Mailer: b4 0.14.2 The pac1921 driver was exposing the available scale info via an ad-hoc ext_info attribute instead of using the read_avail API. This to avoid a possible race condition: while the available current scales were being printed to sysfs by iio core (iio_read_channel_info_avail), the shunt resistor might have been changed concurrently. Switch to the read_avail+release APIs now that the race condition has been addressed. Signed-off-by: Matteo Martelli --- drivers/iio/adc/pac1921.c | 128 ++++++++++++++++------------------------------ 1 file changed, 45 insertions(+), 83 deletions(-) diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c index 4c2a1c07bc399028f0334885fc9cd4552d5892b1..f491a4923380ef9b406a68f8cc413df873869e3e 100644 --- a/drivers/iio/adc/pac1921.c +++ b/drivers/iio/adc/pac1921.c @@ -445,11 +445,52 @@ static int pac1921_read_avail(struct iio_dev *indio_dev, *vals = pac1921_int_num_samples; *length = ARRAY_SIZE(pac1921_int_num_samples); return IIO_AVAIL_LIST; + case IIO_CHAN_INFO_SCALE: + switch (chan->channel) { + case PAC1921_CHAN_VBUS: + *vals = (const int *)pac1921_vbus_scales; + *length = ARRAY_SIZE(pac1921_vbus_scales) * 2; + *type = IIO_VAL_INT_PLUS_NANO; + return IIO_AVAIL_LIST; + + case PAC1921_CHAN_VSENSE: + *vals = (const int *)pac1921_vsense_scales; + *length = ARRAY_SIZE(pac1921_vsense_scales) * 2; + *type = IIO_VAL_INT_PLUS_NANO; + return IIO_AVAIL_LIST; + + case PAC1921_CHAN_CURRENT: { + struct pac1921_priv *priv = iio_priv(indio_dev); + + *length = ARRAY_SIZE(priv->current_scales) * 2; + *type = IIO_VAL_INT_PLUS_NANO; + + guard(mutex)(&priv->lock); + + *vals = kmemdup_array((int *)priv->current_scales, + *length, sizeof(int), GFP_KERNEL); + if (!*vals) + return -ENOMEM; + + return IIO_AVAIL_LIST; + } + default: + return -EINVAL; + } default: return -EINVAL; } } +static void pac1921_read_avail_release_res(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int *vals, long mask) +{ + if (mask == IIO_CHAN_INFO_SCALE && + chan->channel == PAC1921_CHAN_CURRENT) + kfree(vals); +} + /* * Perform configuration update sequence: set the device into read state, then * write the config register and set the device back into integration state. @@ -749,6 +790,7 @@ static int pac1921_read_event_value(struct iio_dev *indio_dev, static const struct iio_info pac1921_iio = { .read_raw = pac1921_read_raw, .read_avail = pac1921_read_avail, + .read_avail_release_resource = pac1921_read_avail_release_res, .write_raw = pac1921_write_raw, .write_raw_get_fmt = pac1921_write_raw_get_fmt, .read_label = pac1921_read_label, @@ -806,88 +848,7 @@ static ssize_t pac1921_write_shunt_resistor(struct iio_dev *indio_dev, return len; } -/* - * Emit on sysfs the list of available scales contained in scales_tbl - * - * TODO:: this function can be replaced with iio_format_avail_list() if the - * latter will ever be exported. - * - * Must be called with lock held if the scales_tbl can change runtime (e.g. for - * the current scales table) - */ -static ssize_t pac1921_format_scale_avail(const int (*const scales_tbl)[2], - size_t size, char *buf) -{ - ssize_t len = 0; - - for (unsigned int i = 0; i < size; i++) { - if (i != 0) { - len += sysfs_emit_at(buf, len, " "); - if (len >= PAGE_SIZE) - return -EFBIG; - } - len += sysfs_emit_at(buf, len, "%d.%09d", scales_tbl[i][0], - scales_tbl[i][1]); - if (len >= PAGE_SIZE) - return -EFBIG; - } - - len += sysfs_emit_at(buf, len, "\n"); - return len; -} - -/* - * Read available scales for a specific channel - * - * NOTE: using extended info insted of iio.read_avail() because access to - * current scales must be locked as they depend on shunt resistor which may - * change runtime. Caller of iio.read_avail() would access the table unlocked - * instead. - */ -static ssize_t pac1921_read_scale_avail(struct iio_dev *indio_dev, - uintptr_t private, - const struct iio_chan_spec *chan, - char *buf) -{ - struct pac1921_priv *priv = iio_priv(indio_dev); - const int (*scales_tbl)[2]; - size_t size; - - switch (chan->channel) { - case PAC1921_CHAN_VBUS: - scales_tbl = pac1921_vbus_scales; - size = ARRAY_SIZE(pac1921_vbus_scales); - return pac1921_format_scale_avail(scales_tbl, size, buf); - - case PAC1921_CHAN_VSENSE: - scales_tbl = pac1921_vsense_scales; - size = ARRAY_SIZE(pac1921_vsense_scales); - return pac1921_format_scale_avail(scales_tbl, size, buf); - - case PAC1921_CHAN_CURRENT: { - guard(mutex)(&priv->lock); - scales_tbl = priv->current_scales; - size = ARRAY_SIZE(priv->current_scales); - return pac1921_format_scale_avail(scales_tbl, size, buf); - } - default: - return -EINVAL; - } -} - -#define PAC1921_EXT_INFO_SCALE_AVAIL { \ - .name = "scale_available", \ - .read = pac1921_read_scale_avail, \ - .shared = IIO_SEPARATE, \ -} - -static const struct iio_chan_spec_ext_info pac1921_ext_info_voltage[] = { - PAC1921_EXT_INFO_SCALE_AVAIL, - {} -}; - static const struct iio_chan_spec_ext_info pac1921_ext_info_current[] = { - PAC1921_EXT_INFO_SCALE_AVAIL, { .name = "shunt_resistor", .read = pac1921_read_shunt_resistor, @@ -911,6 +872,7 @@ static const struct iio_chan_spec pac1921_channels[] = { .type = IIO_VOLTAGE, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE), .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | BIT(IIO_CHAN_INFO_SAMP_FREQ), @@ -928,12 +890,12 @@ static const struct iio_chan_spec pac1921_channels[] = { .indexed = 1, .event_spec = pac1921_overflow_event, .num_event_specs = ARRAY_SIZE(pac1921_overflow_event), - .ext_info = pac1921_ext_info_voltage, }, { .type = IIO_VOLTAGE, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE), .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | BIT(IIO_CHAN_INFO_SAMP_FREQ), @@ -951,12 +913,12 @@ static const struct iio_chan_spec pac1921_channels[] = { .indexed = 1, .event_spec = pac1921_overflow_event, .num_event_specs = ARRAY_SIZE(pac1921_overflow_event), - .ext_info = pac1921_ext_info_voltage, }, { .type = IIO_CURRENT, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), + .info_mask_separate_available = BIT(IIO_CHAN_INFO_SCALE), .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) | BIT(IIO_CHAN_INFO_SAMP_FREQ),