From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 722E2C79F89 for ; Fri, 4 Sep 2026 22:06:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:From: Subject:Message-ID:References:Mime-Version:In-Reply-To:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=gFPQMsmC48q+wz7mUdVX+fcsDqeGsLw2XrmLniTg61k=; b=pglzuusBxjCL2cZGxQ1Tk/Nft3 uYlWq+25y9YyCx0NY/qGFpd9JD7damaaK8spFnMrzm5Q1KbSwVAZpTJ0We2bFuteyxcECDEA0gxL5 40ymkUu/vqxojtfnfhcnIRR8IYOxV8jpoZKzyIq3O85F+woT6m9w/TPf8QUtI7dDXq7mAwVCYRsSs uKHqOGIkkzcqDibVLPZg5IbXkg7NBmzr8iTluxgOq54PRBekOtOa046oAFIYDusWqPegoO7E3x7XO qG9i8e/dirmmngK8gDNUq79DH3bOpyT8iLI+OLgnfiGTodt6f27KPiyIm3nXGVLYHsXFB4o2VDiQP aEVWCpSg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x2c2u-00000003Mot-1evx; Fri, 04 Sep 2026 22:06:04 +0000 Received: from mail-pg1-x548.google.com ([2607:f8b0:4864:20::548]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x2c2s-00000003MoD-1nNN for kexec@lists.infradead.org; Fri, 04 Sep 2026 22:06:03 +0000 Received: by mail-pg1-x548.google.com with SMTP id 41be03b00d2f7-cc1c1cc5206so1780362a12.3 for ; Fri, 04 Sep 2026 15:05:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1788559559; x=1789164359; darn=lists.infradead.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=gFPQMsmC48q+wz7mUdVX+fcsDqeGsLw2XrmLniTg61k=; b=ahTcEZKFztgtzuSP6Ykx2vJLA/mUEucQ5lm4eQ42nVFdObPDgEo9nSDgymydCdykY5 K4i4AZSjIXskSQnF/rT9bE2BAzJzK4Us+ige/rYJydJF+1f1dIuOJOTb+ekxc3CKrXS8 oOPLOcxGrqrnbHswUGLxzTyGjSZ/0Coyj6OTDIr6qRd1rI1X+woBGFaaS1K1nY9ZDB/C W6KphMBB5SVRHiBW2S7zYNT+xvHR3oK68FLlBuuJVvEB0xuIDwhCGrTRCqBA3mt/Uvau lj+85623P2h0P0dJKuSH8Xux4ltB2KwN4jcYVnY8sMfLKm+zrDUCOyeCefvcOl/FrUlX 2QkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788559559; x=1789164359; h=content-type: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:content-type; bh=gFPQMsmC48q+wz7mUdVX+fcsDqeGsLw2XrmLniTg61k=; b=AS5tJKtxlEyejrcqEh+a/GqD5d4zaHjPdUSdsw/AkyukoXK+PpALu35YH5S2BEEnJC a0BrYnmx/JbpdZLr9VG6FoSs7n0FUVru3vefPbyjMgl1l4uyKkQR3/nvqHJzOaVAjTvH xnSBMstWlUOKe7YaqiMQNG5uOzqecoo3qBlgMKLPlHAGS77/CfPfZ1fHKTD2EOOTouXG B/XDiICUqDmuBsLSZdlf1nZxJvcWnE00KoLXnRZDvATWXvefqD0WLZgcBb1JuWH3GfYJ y1Y3s68xrxxgHDgKeZ8K1BAnfDqY29DvTnb7KainVvyS3WMxX8zB4d427iV45dLb/w6V ts3Q== X-Forwarded-Encrypted: i=1; AKwUvBySIXLIY/EbAPLEABdgGhs/dk8MfUoIwQ6zm5uCk4eGLKltiju8RsW4BmtXEcc0pTXmqkHJfQ==@lists.infradead.org X-Gm-Message-State: AFuF++nI+2xVxEfHsDlXBUys+3h4EaxA0DeQrdwlyHmgyBhkM5nd3yog R4dAgU7x1ha1wNbATJ7Q4fb8T2PTUgpy5ukX6pI0k4YQ5s6mg97WWZD6iUJAaQh68ouS8h/N0j+ Vzc2vJxeDONvYiw== X-Received: from pfbhm10.prod.google.com ([2002:a05:6a00:670a:b0:859:a043:9ede]) (user=skhawaja job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:13a2:b0:858:6307:5f7d with SMTP id d2e1a72fcca58-86166dbb899mr12027017b3a.8.1788559558716; Fri, 04 Sep 2026 15:05:58 -0700 (PDT) Date: Fri, 4 Sep 2026 22:05:54 +0000 In-Reply-To: <20260904220555.589752-1-skhawaja@google.com> Mime-Version: 1.0 References: <20260904220555.589752-1-skhawaja@google.com> X-Mailer: git-send-email 2.55.0.1003.g10538fe699-goog Message-ID: <20260904220555.589752-2-skhawaja@google.com> Subject: [PATCH 1/1] liveupdate: luo_file: Add documentation for dependencies From: Samiullah Khawaja To: Pasha Tatashin , Mike Rapoport , Pratyush Yadav , Alexander Graf Cc: Samiullah Khawaja , David Matlack , tarunsahu@google.com, open list , "open list:KEXEC HANDOVER (KHO)" , "open list:KEXEC HANDOVER (KHO)" Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260904_150602_516025_7A12644B X-CRM114-Status: GOOD ( 11.46 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org Add documentation for dependencies between FDs preserved by File Handlers. This supplements the previously added liveupdate_get_token_outgoing() and liveupdate_get_file_incoming() internal APIs to allow File Handlers to resolve dependencies. Signed-off-by: Samiullah Khawaja --- kernel/liveupdate/luo_file.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/kernel/liveupdate/luo_file.c b/kernel/liveupdate/luo_file.c index dbae0715220b..0a4994377c98 100644 --- a/kernel/liveupdate/luo_file.c +++ b/kernel/liveupdate/luo_file.c @@ -91,6 +91,21 @@ * again later. If the issue cannot be resolved, these resources will be held * by LUO until the next live update cycle, at which point they will be * discarded. + * + * Dependencies: + * + * Preserved files may have dependencies on other files that also need to be + * preserved during a live update. A file handler can resolve these dependencies + * by querying the token of the dependency. That token can then be serialized + * and used to fetch the dependency during the retrieve() callback in the next + * kernel. + * + * Some of these dependencies can be resolved late during File Handler freeze() + * callback, but some of these might need resolution during File Handler + * preserve() callback based on the constraints such as immutability and + * performance. This introduces an order of preservation. Note that the order of + * preservation of dependencies can be safely relaxed later, but it cannot be + * enforced later. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt -- 2.55.0.1003.g10538fe699-goog