From nobody Wed Feb 11 05:41:51 2026 Received: from bmailout1.hostsharing.net (bmailout1.hostsharing.net [83.223.95.100]) (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 D716C8F6C for ; Sat, 20 Apr 2024 20:02:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=83.223.95.100 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713643377; cv=none; b=Iukrm6OoU37BKkZeddeM088T+x+BCgXZGsmbWTttKarb50NF3HeIzU/+4ghbeOmeut1+8Y0DC4NftuIpBT1haYIx95cJWmMSU/DOxs3O/y26ReOpmlSn3sZjMeYMRW0GLoiPU41qRRr2TFYddCFrURHJhj+Qh+tCq37xFH+qeGs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713643377; c=relaxed/simple; bh=+JxH8dFXAsGZnl1VN1Unl6FLp+2yGtti2ERqBLuV1AQ=; h=Message-ID:In-Reply-To:References:From:Date:Subject:To:Cc; b=k7ymzgtz0WEVa+p/a9O6C5K5TP+OcOSoV2SUyuGuzN+3YE5HRZpNJ7VZ7BH22p1cQ+qyOHRjApqdyW+F093N6Kwv9z6dZO1eRi/eF5LpqNXegRVGckfDI8x5Z20h/y4Bfw+YXZq6gNVYNWM0X+pbw2bW3BSVRgzLsgnYepApAxY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de; spf=pass smtp.mailfrom=wunner.de; arc=none smtp.client-ip=83.223.95.100 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=wunner.de Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS RSA CA G1" (verified OK)) by bmailout1.hostsharing.net (Postfix) with ESMTPS id A1B9C30008F1A; Sat, 20 Apr 2024 22:02:46 +0200 (CEST) Received: by h08.hostsharing.net (Postfix, from userid 100393) id 9AB0ACC66D; Sat, 20 Apr 2024 22:02:46 +0200 (CEST) Message-ID: <2e3eaaf2600bb55c0415c23ba301e809403a7aa2.1713608122.git.lukas@wunner.de> In-Reply-To: References: From: Lukas Wunner Date: Sat, 20 Apr 2024 22:00:01 +0200 Subject: [PATCH 1/6] driver core: Add device_show_string() helper for sysfs attributes To: Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org Cc: Michael Ellerman , linuxppc-dev@lists.ozlabs.org Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" For drivers wishing to expose an unsigned long, int or bool at a static memory location in sysfs, the driver core provides ready-made helpers such as device_show_ulong() to be used as ->show() callback. Some drivers need to expose a string and so far they all provide their own ->show() implementation. arch/powerpc/perf/hv-24x7.c went so far as to create a device_show_string() helper but kept it private. Make it public for reuse by other drivers. The pattern seems to be sufficiently frequent to merit a public helper. Add a DEVICE_STRING_ATTR_RO() macro in line with the existing DEVICE_ULONG_ATTR() and similar macros to ease declaration of string attributes. Signed-off-by: Lukas Wunner Acked-by: Michael Ellerman (powerpc) --- arch/powerpc/perf/hv-24x7.c | 10 ---------- drivers/base/core.c | 9 +++++++++ include/linux/device.h | 15 +++++++++++++++ 3 files changed, 24 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c index 057ec2e3451d..d400fa391c27 100644 --- a/arch/powerpc/perf/hv-24x7.c +++ b/arch/powerpc/perf/hv-24x7.c @@ -425,16 +425,6 @@ static char *memdup_to_str(char *maybe_str, int max_le= n, gfp_t gfp) return kasprintf(gfp, "%.*s", max_len, maybe_str); } =20 -static ssize_t device_show_string(struct device *dev, - struct device_attribute *attr, char *buf) -{ - struct dev_ext_attribute *d; - - d =3D container_of(attr, struct dev_ext_attribute, attr); - - return sprintf(buf, "%s\n", (char *)d->var); -} - static ssize_t cpumask_show(struct device *dev, struct device_attribute *attr, char *buf) { diff --git a/drivers/base/core.c b/drivers/base/core.c index 78dfa74ee18b..190d4a39c6a8 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2523,6 +2523,15 @@ ssize_t device_show_bool(struct device *dev, struct = device_attribute *attr, } EXPORT_SYMBOL_GPL(device_show_bool); =20 +ssize_t device_show_string(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_ext_attribute *ea =3D to_ext_attr(attr); + + return sysfs_emit(buf, "%s\n", (char *)ea->var); +} +EXPORT_SYMBOL_GPL(device_show_string); + /** * device_release - free device structure. * @kobj: device's kobject. diff --git a/include/linux/device.h b/include/linux/device.h index c515ba5756e4..63ac65db3ecb 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -132,6 +132,8 @@ ssize_t device_show_bool(struct device *dev, struct dev= ice_attribute *attr, char *buf); ssize_t device_store_bool(struct device *dev, struct device_attribute *att= r, const char *buf, size_t count); +ssize_t device_show_string(struct device *dev, struct device_attribute *at= tr, + char *buf); =20 /** * DEVICE_ATTR - Define a device attribute. @@ -251,6 +253,19 @@ ssize_t device_store_bool(struct device *dev, struct d= evice_attribute *attr, struct dev_ext_attribute dev_attr_##_name =3D \ { __ATTR(_name, _mode, device_show_bool, device_store_bool), &(_var) } =20 +/** + * DEVICE_STRING_ATTR_RO - Define a device attribute backed by a r/o strin= g. + * @_name: Attribute name. + * @_mode: File mode. + * @_var: Identifier of string. + * + * Like DEVICE_ULONG_ATTR(), but @_var is a string. Because the length of = the + * string allocation is unknown, the attribute must be read-only. + */ +#define DEVICE_STRING_ATTR_RO(_name, _mode, _var) \ + struct dev_ext_attribute dev_attr_##_name =3D \ + { __ATTR(_name, (_mode) & ~0222, device_show_string, NULL), (_var) } + #define DEVICE_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \ struct device_attribute dev_attr_##_name =3D \ __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) --=20 2.43.0