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 B6F791AF0C0; Wed, 19 Feb 2025 08:42:16 +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=1739954536; cv=none; b=BoGnMoo7fIT7zOh4/AdKclqChgRdkwrIoseJ9oGIVvVrGiJQTcMFUw6H02HZKgvOM9dR/D+pZ9JGCGO8SAdl73g7t4LjBPVE3OFqu3ozkEwUz672n9NaaicjHKsOCmLTCHg5QPnv2crlJYIxYG0Dk5D1hqcaiGh+KqXWY27kwLg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739954536; c=relaxed/simple; bh=jjzw1kmhezodiER2xMW+2x0NHsd3E7gPZvWTWo8Ebs8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=L+uiHeRHaNJ+w1GTd9LQEn9mxvuRCyOLTGXzleL3JQL+BJPyFcJazAaBI46w8WxMKZzPTaMmYKCFMqcF5eR7n+jCQsxVxUaUDTRvhQkMayx5qW/rMcX9WXDEDq98K89tWNsbctDMjET2FeFgoeGLuPfTt0NF+pUrxK5BBatPZlw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=geR+XHlU; 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="geR+XHlU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FAE9C4CED1; Wed, 19 Feb 2025 08:42:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739954536; bh=jjzw1kmhezodiER2xMW+2x0NHsd3E7gPZvWTWo8Ebs8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=geR+XHlUFCfKTzN7ejBf4pWTbeY991c5fKYDr/ahpvssZ9rBMLiKZhrdNmIY1kri2 tiayKKjPBIK6WIqAAxg0Hr/j8K3xM6gCvXdjcWK9o1VV3EBpJibOLqIOsUliF+HGoY V2OpfM+CH2Q0247DLmWWpL7pSbgLWHYs3TeCBUSo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Joe Damato , Eric Dumazet , Kuniyuki Iwashima , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.13 233/274] net: add netdev->up protected by netdev_lock() Date: Wed, 19 Feb 2025 09:28:07 +0100 Message-ID: <20250219082618.698868926@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250219082609.533585153@linuxfoundation.org> References: <20250219082609.533585153@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jakub Kicinski [ Upstream commit 5112457f3d8e41f987908266068af88ef9f3ab78 ] Some uAPI (netdev netlink) hide net_device's sub-objects while the interface is down to ensure uniform behavior across drivers. To remove the rtnl_lock dependency from those uAPIs we need a way to safely tell if the device is down or up. Add an indication of whether device is open or closed, protected by netdev->lock. The semantics are the same as IFF_UP, but taking netdev_lock around every write to ->flags would be a lot of code churn. We don't want to blanket the entire open / close path by netdev_lock, because it will prevent us from applying it to specific structures - core helpers won't be able to take that lock from any function called by the drivers on open/close paths. So the state of the flag is "pessimistic", as in it may report false negatives, but never false positives. Reviewed-by: Joe Damato Reviewed-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250115035319.559603-5-kuba@kernel.org Signed-off-by: Jakub Kicinski Stable-dep-of: 011b03359038 ("Revert "net: skb: introduce and use a single page frag cache"") Signed-off-by: Sasha Levin --- include/linux/netdevice.h | 14 +++++++++++++- net/core/dev.c | 4 ++-- net/core/dev.h | 12 ++++++++++++ 3 files changed, 27 insertions(+), 3 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 47f817bcea503..64013fd389f28 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -2441,12 +2441,24 @@ struct net_device { unsigned long gro_flush_timeout; u32 napi_defer_hard_irqs; + /** + * @up: copy of @state's IFF_UP, but safe to read with just @lock. + * May report false negatives while the device is being opened + * or closed (@lock does not protect .ndo_open, or .ndo_close). + */ + bool up; + /** * @lock: netdev-scope lock, protects a small selection of fields. * Should always be taken using netdev_lock() / netdev_unlock() helpers. * Drivers are free to use it for other protection. * - * Protects: @reg_state, @net_shaper_hierarchy. + * Protects: + * @net_shaper_hierarchy, @reg_state + * + * Partially protects (writers must hold both @lock and rtnl_lock): + * @up + * * Ordering: take after rtnl_lock. */ struct mutex lock; diff --git a/net/core/dev.c b/net/core/dev.c index 75996e1aac46c..67f2bb84db543 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1512,7 +1512,7 @@ static int __dev_open(struct net_device *dev, struct netlink_ext_ack *extack) if (ret) clear_bit(__LINK_STATE_START, &dev->state); else { - dev->flags |= IFF_UP; + netif_set_up(dev, true); dev_set_rx_mode(dev); dev_activate(dev); add_device_randomness(dev->dev_addr, dev->addr_len); @@ -1591,7 +1591,7 @@ static void __dev_close_many(struct list_head *head) if (ops->ndo_stop) ops->ndo_stop(dev); - dev->flags &= ~IFF_UP; + netif_set_up(dev, false); netpoll_poll_enable(dev); } } diff --git a/net/core/dev.h b/net/core/dev.h index deb5eae5749fa..e17c640c05fb9 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -111,6 +111,18 @@ void __dev_notify_flags(struct net_device *dev, unsigned int old_flags, void unregister_netdevice_many_notify(struct list_head *head, u32 portid, const struct nlmsghdr *nlh); +static inline void netif_set_up(struct net_device *dev, bool value) +{ + if (value) + dev->flags |= IFF_UP; + else + dev->flags &= ~IFF_UP; + + netdev_lock(dev); + dev->up = value; + netdev_unlock(dev); +} + static inline void netif_set_gso_max_size(struct net_device *dev, unsigned int size) { -- 2.39.5