From patchwork Sun Sep 29 09:21:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dragan Simic X-Patchwork-Id: 831483 Received: from mail.manjaro.org (mail.manjaro.org [116.203.91.91]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB77213C3CD; Sun, 29 Sep 2024 09:22:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=116.203.91.91 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727601759; cv=none; b=BlFSYyEf+EiIDrXDsPLC6N+7IZm/Khz3hBze4VfOiJUImSaEQNsBx3mo+O2zl5RZNVYJH5qQiTfpklVpMQcKh8ioW0EoBdgM5tqWA73mnmx5/Q8yUjue5r9ZpVLkANnH1CMpiRyHLsqSQlLZlaIdqhWSu/6gtkP8M9bRbFW70CU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727601759; c=relaxed/simple; bh=6Yi5HucFpGn1vLMidv2Pv6SSVoebYZfE0QhcyiONPvI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=dWHYTX3Phuld+Jj7eH1iDuodoL0nrnw9/K//pIi8LsG8lPm+qnKl0kgXkJ1qlk4ugzd0QF//gFImGdKTCyHrZi8muAFaI8sd2H1PLF3SJQBUQT8lXPfun5ehDHjDVmDrmGoJzVy9PhLuttPqC/9KeV1cLK4zAZdVwdra+YRZ/xY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=manjaro.org; spf=pass smtp.mailfrom=manjaro.org; dkim=pass (2048-bit key) header.d=manjaro.org header.i=@manjaro.org header.b=SQzVQMAM; arc=none smtp.client-ip=116.203.91.91 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=manjaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=manjaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=manjaro.org header.i=@manjaro.org header.b="SQzVQMAM" From: Dragan Simic DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=manjaro.org; s=2021; t=1727601744; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VVqzY/8n0kj3yAF96lmKr1C9k/wOn5fp+Ckfts8zEko=; b=SQzVQMAM2CP0fe/Y0AL8iWa5e9oNhoOCl2GK2YZhWRAXhWYP82MOtxJPUUbtP4PHCjXUc3 vvzN7PQB9etip21RLoZnNsY9dLHJla7REwNKlx8RAb+DMhfgP5905MXDRUpeojLL0ZeNBe RLfiFY95WvF7mAfgl/ZkGpdVubzQd9R04MTxqYiSR9ikDwD6+k94V+qlPQ+7PcmD8s3mWj 2u/N5qukwQ5jGgWUF79ktBOBztAcCHoO2sFyHPzMZI+BE7PwJz/MeLBAmnYp5amQuIBBzN qW/c7F3unxboekjK4eZOKgkhZx9xXwbddchiBNPESaYO88oiad14V2ZF9hGCAQ== To: linux-spi@vger.kernel.org, linux-rockchip@lists.infradead.org Cc: broonie@kernel.org, heiko@sntech.de, gregkh@linuxfoundation.org, rafael@kernel.org, oss@helene.moe, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 4/5] driver core: Add device probe log helper dev_warn_probe() Date: Sun, 29 Sep 2024 11:21:16 +0200 Message-Id: <2be0a28538bb2a3d1bcc91e2ca1f2d0dc09146d9.1727601608.git.dsimic@manjaro.org> In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Authentication-Results: ORIGINATING; auth=pass smtp.auth=dsimic@manjaro.org smtp.mailfrom=dsimic@manjaro.org Some drivers can still provide their functionality to a certain extent even some of their resource acquisitions eventually fail. In such cases, emitting errors isn't the desired action, but warnings should be emitted instead. To solve this, introduce dev_warn_probe() as a new device probe log helper, which behaves identically as the already existing dev_err_probe(), while it produces warnings instead of errors. The intended use is with the resources that are actually optional for a particular driver. While there, copyedit the kerneldoc for dev_err_probe() a bit, to simplify its wording a bit, and reuse it as the kerneldoc for dev_warn_probe(), with the necessary wording adjustments, of course. Signed-off-by: Dragan Simic --- drivers/base/core.c | 129 +++++++++++++++++++++++++++++-------- include/linux/dev_printk.h | 1 + 2 files changed, 102 insertions(+), 28 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 8c0733d3aad8..f2e41db0c09f 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4982,71 +4982,144 @@ define_dev_printk_level(_dev_info, KERN_INFO); #endif +static void __dev_probe_failed(const struct device *dev, int err, bool fatal, + const char *fmt, va_list vargsp) +{ + struct va_format vaf; + va_list vargs; + + /* + * On x86_64 and possibly on other architectures, va_list is actually a + * size-1 array containing a structure. As a result, function parameter + * vargps decays from T[1] to T*, and &vargsp has type T** rather than + * T(*)[1], which is expected by its assignment to vaf.va below. + * + * One standard way to solve this mess is by creating a copy in a local + * variable of type va_list and then using a pointer to that local copy + * instead, which is the approach employed here. + */ + va_copy(vargs, vargsp); + + vaf.fmt = fmt; + vaf.va = &vargs; + + switch (err) { + case -EPROBE_DEFER: + device_set_deferred_probe_reason(dev, &vaf); + dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf); + break; + + case -ENOMEM: + /* Don't print anything on -ENOMEM, there's already enough output */ + break; + + default: + /* Log fatal final failures as errors, otherwise produce warnings */ + if (fatal) + dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf); + else + dev_warn(dev, "error %pe: %pV", ERR_PTR(err), &vaf); + break; + } + + va_end(vargs); +} + /** * dev_err_probe - probe error check and log helper * @dev: the pointer to the struct device * @err: error value to test * @fmt: printf-style format string * @...: arguments as specified in the format string * * This helper implements common pattern present in probe functions for error * checking: print debug or error message depending if the error value is * -EPROBE_DEFER and propagate error upwards. * In case of -EPROBE_DEFER it sets also defer probe reason, which can be * checked later by reading devices_deferred debugfs attribute. - * It replaces code sequence:: + * It replaces the following code sequence:: * * if (err != -EPROBE_DEFER) * dev_err(dev, ...); * else * dev_dbg(dev, ...); * return err; * * with:: * * return dev_err_probe(dev, err, ...); * - * Using this helper in your probe function is totally fine even if @err is - * known to never be -EPROBE_DEFER. + * Using this helper in your probe function is totally fine even if @err + * is known to never be -EPROBE_DEFER. * The benefit compared to a normal dev_err() is the standardized format - * of the error code, it being emitted symbolically (i.e. you get "EAGAIN" - * instead of "-35") and the fact that the error code is returned which allows - * more compact error paths. + * of the error code, which is emitted symbolically (i.e. you get "EAGAIN" + * instead of "-35"), and having the error code returned allows more + * compact error paths. * * Returns @err. */ int dev_err_probe(const struct device *dev, int err, const char *fmt, ...) { - struct va_format vaf; - va_list args; + va_list vargs; - va_start(args, fmt); - vaf.fmt = fmt; - vaf.va = &args; + va_start(vargs, fmt); - switch (err) { - case -EPROBE_DEFER: - device_set_deferred_probe_reason(dev, &vaf); - dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf); - break; + /* Use dev_err() for logging when err doesn't equal -EPROBE_DEFER */ + __dev_probe_failed(dev, err, true, fmt, vargs); - case -ENOMEM: - /* - * We don't print anything on -ENOMEM, there is already enough - * output. - */ - break; + va_end(vargs); - default: - dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf); - break; - } + return err; +} +EXPORT_SYMBOL_GPL(dev_err_probe); - va_end(args); +/** + * dev_warn_probe - probe error check and log helper + * @dev: the pointer to the struct device + * @err: error value to test + * @fmt: printf-style format string + * @...: arguments as specified in the format string + * + * This helper implements common pattern present in probe functions for error + * checking: print debug or warning message depending if the error value is + * -EPROBE_DEFER and propagate error upwards. + * In case of -EPROBE_DEFER it sets also defer probe reason, which can be + * checked later by reading devices_deferred debugfs attribute. + * It replaces the following code sequence:: + * + * if (err != -EPROBE_DEFER) + * dev_warn(dev, ...); + * else + * dev_dbg(dev, ...); + * return err; + * + * with:: + * + * return dev_warn_probe(dev, err, ...); + * + * Using this helper in your probe function is totally fine even if @err + * is known to never be -EPROBE_DEFER. + * The benefit compared to a normal dev_warn() is the standardized format + * of the error code, which is emitted symbolically (i.e. you get "EAGAIN" + * instead of "-35"), and having the error code returned allows more + * compact error paths. + * + * Returns @err. + */ +int dev_warn_probe(const struct device *dev, int err, const char *fmt, ...) +{ + va_list vargs; + + va_start(vargs, fmt); + + /* Use dev_warn() for logging when err doesn't equal -EPROBE_DEFER */ + __dev_probe_failed(dev, err, false, fmt, vargs); + + va_end(vargs); return err; } -EXPORT_SYMBOL_GPL(dev_err_probe); +EXPORT_SYMBOL_GPL(dev_warn_probe); static inline bool fwnode_is_primary(struct fwnode_handle *fwnode) { diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h index ca32b5bb28eb..eb2094e43050 100644 --- a/include/linux/dev_printk.h +++ b/include/linux/dev_printk.h @@ -276,6 +276,7 @@ do { \ dev_driver_string(dev), dev_name(dev), ## arg) __printf(3, 4) int dev_err_probe(const struct device *dev, int err, const char *fmt, ...); +__printf(3, 4) int dev_warn_probe(const struct device *dev, int err, const char *fmt, ...); /* Simple helper for dev_err_probe() when ERR_PTR() is to be returned. */ #define dev_err_ptr_probe(dev, ___err, fmt, ...) \