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 3C0C12D97AA; Mon, 17 Nov 2025 10:16:19 +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=1763374580; cv=none; b=uj7Zi2NQsb6sXWvp48p4tQAKj+eza3lPYONEGyaydvVhtFJs8KYBgxd47+D1+gd/7doFTfZPiXOOxOnOa5mhCtsqVJ607+UNUdzzpkd3QJ55R5ffxIuYNzA5CuR+Pup2+0s5g6d+YVAgA7KHqRJm2ys2y1OAc31xKGol92dRtmY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763374580; c=relaxed/simple; bh=3pqt/emoxDXMJPc9sIUv8mSiIo4NlUAIW0OPRzW2AvE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=X6Zd546okZW1EuOQcN+w0GQozfL7/YklU8zzbwwPLhSmuXU4GFqhqRECUUIbD9mcHkqXambRpQ5r9w6TSBLknz/BsaiQukpM13hYV4y/E5480GanaZrhLdmRESVXIOPm7NHOLT+bsou8OBosxaqsXl8aLjRjjF5OoR08HgIGlnI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dVxQd+jd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dVxQd+jd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6CA8CC19422; Mon, 17 Nov 2025 10:16:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763374579; bh=3pqt/emoxDXMJPc9sIUv8mSiIo4NlUAIW0OPRzW2AvE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dVxQd+jd5trmwBgh/3zu4hTlLkx/9p5IL33qFYnWaBIb3WLOyiuAgzqHpcoyY8DvC ZKiyBaH9cpng8Pso5NAbKGCW1AMqksvLeji0z7vLUtQynPZB7dfXmSo5pGdXpGyo+1 9y1zMypZS9pqu5U01wxSxH6kHOxp1xOme4U3op9CTwfVOcLKDGW9HLxzfcokqvHM1X N5dXERXMh6/b5uyPBs0Z2qK1b8rH9LyONeVyW6Q8jsrspPSPTwlC3Vk/hn6kNAKrIF IkGYpSBwyj2A2bCkDZfCTKCKnmMjwvr+Fr8ufs+Q1LYALnWpYdlaUoyTJeOPu56txT eO8bZlmOwn+hA== Date: Mon, 17 Nov 2025 12:15:57 +0200 From: Mike Rapoport To: Pasha Tatashin Cc: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, ptyadav@amazon.de, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com, hughd@google.com, skhawaja@google.com, chrisl@kernel.org Subject: Re: [PATCH v6 14/20] liveupdate: luo_file: add private argument to store runtime state Message-ID: References: <20251115233409.768044-1-pasha.tatashin@soleen.com> <20251115233409.768044-15-pasha.tatashin@soleen.com> Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251115233409.768044-15-pasha.tatashin@soleen.com> On Sat, Nov 15, 2025 at 06:34:00PM -0500, Pasha Tatashin wrote: > From: Pratyush Yadav > > Currently file handlers only get the serialized_data field to store > their state. This field has a pointer to the serialized state of the > file, and it becomes a part of LUO file's serialized state. > > File handlers can also need some runtime state to track information that > shouldn't make it in the serialized data. > > One such example is a vmalloc pointer. While kho_preserve_vmalloc() > preserves the memory backing a vmalloc allocation, it does not store the > original vmap pointer, since that has no use being passed to the next > kernel. The pointer is needed to free the memory in case the file is > unpreserved. > > Provide a private field in struct luo_file and pass it to all the > callbacks. The field's can be set by preserve, and must be freed by > unpreserve. > > Signed-off-by: Pratyush Yadav > Co-developed-by: Pasha Tatashin > Signed-off-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) > --- > include/linux/liveupdate.h | 5 +++++ > kernel/liveupdate/luo_file.c | 9 +++++++++ > 2 files changed, 14 insertions(+) > > diff --git a/include/linux/liveupdate.h b/include/linux/liveupdate.h > index 36a831ae3ead..defc69a1985d 100644 > --- a/include/linux/liveupdate.h > +++ b/include/linux/liveupdate.h > @@ -29,6 +29,10 @@ struct file; > * this to the file being operated on. > * @serialized_data: The opaque u64 handle, preserve/prepare/freeze may update > * this field. > + * @private_data: Private data for the file used to hold runtime state that > + * is not preserved. Set by the handler's .preserve() > + * callback, and must be freed in the handler's > + * .unpreserve() callback. > * > * This structure bundles all parameters for the file operation callbacks. > * The 'data' and 'file' fields are used for both input and output. > @@ -39,6 +43,7 @@ struct liveupdate_file_op_args { > bool retrieved; > struct file *file; > u64 serialized_data; > + void *private_data; > }; > > /** > diff --git a/kernel/liveupdate/luo_file.c b/kernel/liveupdate/luo_file.c > index 3d3bd84cb281..df337c9c4f21 100644 > --- a/kernel/liveupdate/luo_file.c > +++ b/kernel/liveupdate/luo_file.c > @@ -126,6 +126,10 @@ static LIST_HEAD(luo_file_handler_list); > * This handle is passed back to the handler's .freeze(), > * .retrieve(), and .finish() callbacks, allowing it to track > * and update its serialized state across phases. > + * @private_data: Pointer to the private data for the file used to hold runtime > + * state that is not preserved. Set by the handler's .preserve() > + * callback, and must be freed in the handler's .unpreserve() > + * callback. > * @retrieved: A flag indicating whether a user/kernel in the new kernel has > * successfully called retrieve() on this file. This prevents > * multiple retrieval attempts. > @@ -152,6 +156,7 @@ struct luo_file { > struct liveupdate_file_handler *fh; > struct file *file; > u64 serialized_data; > + void *private_data; > bool retrieved; > struct mutex mutex; > struct list_head list; > @@ -309,6 +314,7 @@ int luo_preserve_file(struct luo_session *session, u64 token, int fd) > goto exit_err; > } else { > luo_file->serialized_data = args.serialized_data; > + luo_file->private_data = args.private_data; > list_add_tail(&luo_file->list, &session->files_list); > session->count++; > } > @@ -356,6 +362,7 @@ void luo_file_unpreserve_files(struct luo_session *session) > args.session = (struct liveupdate_session *)session; > args.file = luo_file->file; > args.serialized_data = luo_file->serialized_data; > + args.private_data = luo_file->private_data; > luo_file->fh->ops->unpreserve(&args); > luo_flb_file_unpreserve(luo_file->fh); > > @@ -384,6 +391,7 @@ static int luo_file_freeze_one(struct luo_session *session, > args.session = (struct liveupdate_session *)session; > args.file = luo_file->file; > args.serialized_data = luo_file->serialized_data; > + args.private_data = luo_file->private_data; > > err = luo_file->fh->ops->freeze(&args); > if (!err) > @@ -405,6 +413,7 @@ static void luo_file_unfreeze_one(struct luo_session *session, > args.session = (struct liveupdate_session *)session; > args.file = luo_file->file; > args.serialized_data = luo_file->serialized_data; > + args.private_data = luo_file->private_data; > > luo_file->fh->ops->unfreeze(&args); > } > -- > 2.52.0.rc1.455.g30608eb744-goog > -- Sincerely yours, Mike.