From patchwork Wed Feb 7 14:26:21 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 13548581 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (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 67E3E7E567 for ; Wed, 7 Feb 2024 14:26:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707316004; cv=none; b=lbFbEPhH/G+FjxPlu9M8i+EGOTvQwirHxE8IqdGTUPuP8blhQYmlb3KO4nVssKYyF80V01ObBnvG64Xr1DK4E4RVB7Q4qkxJ3w9kE/yzCU7s5xXGsgbX1j+9dkWpFu/CpBhI7HPtz9dDL/GfsSH1Fm7FXIZ+QelTtpDff/5dPjw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707316004; c=relaxed/simple; bh=A1AxBIRilVUDb4+CoB/1XBXgN6/J1A53bxW2BFyc0Zw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Y9WQy4n9deS39+fo0iHEVQhIS69LtSdhPAa+h5I0rCIxDl+MhAQ5+8/eHDm9GXSw4imnkWFrhi5n3Y8XM10e8CES4ZKh1vtHKTOTV1+TlC2JqqNODBXBr8/B9hpkSehMPS0Ehiggv0uPb/24I0MUVgRne0qJk8P+51RMx0AfoV0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=zHz9XbDY; arc=none smtp.client-ip=209.85.219.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="zHz9XbDY" Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-dc6cd10fd94so971046276.3 for ; Wed, 07 Feb 2024 06:26:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707316002; x=1707920802; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=IhbWSbuWjf05VEZa3YQG76+cdv9gP/2iSpbLXiukNbY=; b=zHz9XbDYViz9sCx+MUcLWhj5wq7hiKKpUd8bmiuv5iCkRTgo1Ey7GMVeeWzvvO0GDx NYbzWtDfOcGZ/CsynpTW5vHnKE68sSc68HHTPrb68XFDzd3a1lf3cWgUdi4g4cAhD89A Rt5CMNiSif5bT17nlPHZHMEvFEUk44VIULVjNV5II91wgM5kUiyhYRZcCQA26wszJHXz ZWPaypVVor58OcByQZzxN4MhjILt61RMewebMzLxgo/9564Zy9smz3I1rJaPZnXkYySd 5N7RKVD8B7jnlbzlOFLd60PHCO53XUvDX8i/wnsF9XXknOjLCiZFF/qLv/eZ1csDL2h9 Rsog== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707316002; x=1707920802; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=IhbWSbuWjf05VEZa3YQG76+cdv9gP/2iSpbLXiukNbY=; b=g7rKiKCY4ASfeWxXsBPVE2LeLVlY4mPWDMVQ9PmAPUAfyJGz9J7bk9NDioboY1uB+9 fif5dFmtAis0Gfi1kYUlWes6acdsSRT8Czs/180Mo/L4hArcc87V/ZXY8k5FncfDKynA q0TWcgG877SUi8ywGwMCq+KeI9NRdqqGKMqB/5ymUvsJDorCeH72/z13oBYwmgCvJRHU 70QM3sGYyduSqr638wIa6fkTSKNpQaQZSBwAz3GVUWWfA3HslZUMDhRJQeEoOilMDQWD 46v7Lx1NEkwitYzWjoYnb6ItJiQcyeIotcLU6kOc/tZH9U109OhUVG1yri/GGE+bz2T2 m7TQ== X-Gm-Message-State: AOJu0Yw2uRvRmfnMmthdHydT/In0eQqcX5nFD0/vTHRBjIGLflEw9T2I 4ZJNSIjnt1eXi68HA2/c+9B43fn5lRWriVHcnxap6TDWh1Gni+PcRp0WtVZ431Oi12JAm1j1ufO jRkBSxTdTmg== X-Google-Smtp-Source: AGHT+IFA1YkTDDSyFBuvjfdqiCmM8AjRiIg4cuhFnyfMi/bpkhEVW5CNzKW3qxWGavMBCJ2Wmkxfifd06MTitw== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:395a]) (user=edumazet job=sendgmr) by 2002:a05:6902:1b91:b0:dc2:23f5:1791 with SMTP id ei17-20020a0569021b9100b00dc223f51791mr1219089ybb.6.1707316002457; Wed, 07 Feb 2024 06:26:42 -0800 (PST) Date: Wed, 7 Feb 2024 14:26:21 +0000 In-Reply-To: <20240207142629.3456570-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240207142629.3456570-1-edumazet@google.com> X-Mailer: git-send-email 2.43.0.594.gd9cf4e227d-goog Message-ID: <20240207142629.3456570-6-edumazet@google.com> Subject: [PATCH net-next 05/13] net-sysfs: convert netdev_show() to RCU From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet X-Patchwork-Delegate: kuba@kernel.org Make clear dev_isalive() can be called with RCU protection. Then convert netdev_show() to RCU, to remove dev_base_lock dependency. Also add RCU to broadcast_show(). Signed-off-by: Eric Dumazet --- net/core/net-sysfs.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index f4c2b82674951bbeefd880ca22c54e6a32c9f988..678e4be690821c5cdb933f5e91af2247ebecb830 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -34,10 +34,10 @@ static const char fmt_dec[] = "%d\n"; static const char fmt_ulong[] = "%lu\n"; static const char fmt_u64[] = "%llu\n"; -/* Caller holds RTNL or dev_base_lock */ +/* Caller holds RTNL, RCU or dev_base_lock */ static inline int dev_isalive(const struct net_device *dev) { - return dev->reg_state <= NETREG_REGISTERED; + return READ_ONCE(dev->reg_state) <= NETREG_REGISTERED; } /* use same locking rules as GIF* ioctl's */ @@ -48,10 +48,10 @@ static ssize_t netdev_show(const struct device *dev, struct net_device *ndev = to_net_dev(dev); ssize_t ret = -EINVAL; - read_lock(&dev_base_lock); + rcu_read_lock(); if (dev_isalive(ndev)) ret = (*format)(ndev, buf); - read_unlock(&dev_base_lock); + rcu_read_unlock(); return ret; } @@ -60,7 +60,7 @@ static ssize_t netdev_show(const struct device *dev, #define NETDEVICE_SHOW(field, format_string) \ static ssize_t format_##field(const struct net_device *dev, char *buf) \ { \ - return sysfs_emit(buf, format_string, dev->field); \ + return sysfs_emit(buf, format_string, READ_ONCE(dev->field)); \ } \ static ssize_t field##_show(struct device *dev, \ struct device_attribute *attr, char *buf) \ @@ -161,10 +161,13 @@ static ssize_t broadcast_show(struct device *dev, struct device_attribute *attr, char *buf) { struct net_device *ndev = to_net_dev(dev); + int ret = -EINVAL; + rcu_read_lock(); if (dev_isalive(ndev)) - return sysfs_format_mac(buf, ndev->broadcast, ndev->addr_len); - return -EINVAL; + ret = sysfs_format_mac(buf, ndev->broadcast, ndev->addr_len); + rcu_read_unlock(); + return ret; } static DEVICE_ATTR_RO(broadcast);