From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 5D1243587D9; Thu, 22 Jan 2026 16:33:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769099605; cv=none; b=KaO6V5b4gZxVldpEIIwMvYEvZFf2ucsB2S7pzcksBvsodlI4EJsXQpmi9xPm1cfAsHKO3sJEg3hLfJdQe/yEh4IEqeceuIuFcVap4XKRvfdv3iUJeaxG4nAUIwvx3omwQNPo0MlvIRRjiHtYk2LRSc4GJVhWvEPaRD3mPZ4oMdw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769099605; c=relaxed/simple; bh=wn1urjTtvfUYYMyYs8VAtdp6iF2y3WhCtxkayhL+ioU=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=c3Vgvm3AvRGr5Jhd0efFuoPqloejYlv0epc5yNLbJ4fME8aJJCtYtu7oqWozo7eDVOhiOxbqYnoxXDSpaCwHeeayvXU3wDFfiKGqmbN3hPlZcJXI1kGkOpZ8mQqw/L81dX1eZD1a4wwYe+YbkLl1UzPmKnsG5pNLJl1HHY9KghI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.224.150]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4dxmnM5ltlzHnGf4; Fri, 23 Jan 2026 00:32:39 +0800 (CST) Received: from dubpeml500005.china.huawei.com (unknown [7.214.145.207]) by mail.maildlp.com (Postfix) with ESMTPS id C56264056A; Fri, 23 Jan 2026 00:33:15 +0800 (CST) Received: from localhost (10.203.177.15) by dubpeml500005.china.huawei.com (7.214.145.207) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 22 Jan 2026 16:33:14 +0000 Date: Thu, 22 Jan 2026 16:33:13 +0000 From: Jonathan Cameron To: Smita Koralahalli CC: , , , , , Ard Biesheuvel , "Alison Schofield" , Vishal Verma , Ira Weiny , Dan Williams , Yazen Ghannam , "Dave Jiang" , Davidlohr Bueso , "Matthew Wilcox" , Jan Kara , "Rafael J . Wysocki" , Len Brown , Pavel Machek , Li Ming , Jeff Johnson , Ying Huang , Yao Xingtao , "Peter Zijlstra" , Greg Kroah-Hartman , Nathan Fontenot , Terry Bowman , Robert Richter , Benjamin Cheatham , Zhijian Li , Borislav Petkov , Tomasz Wolski Subject: Re: [PATCH v5 5/7] dax: Introduce dax_cxl_mode for CXL coordination Message-ID: <20260122163313.00003e22@huawei.com> In-Reply-To: <20260122045543.218194-6-Smita.KoralahalliChannabasappa@amd.com> References: <20260122045543.218194-1-Smita.KoralahalliChannabasappa@amd.com> <20260122045543.218194-6-Smita.KoralahalliChannabasappa@amd.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500009.china.huawei.com (7.191.174.84) To dubpeml500005.china.huawei.com (7.214.145.207) On Thu, 22 Jan 2026 04:55:41 +0000 Smita Koralahalli wrote: > Introduce dax_cxl_mode to coordinate between dax_cxl and dax_hmem when > handling CXL tagged memory ranges. > > This patch defines the dax_cxl_mode enum and establishes a default policy. > Subsequent patches will wire this into dax_cxl and dax_hmem to decide > whether CXL tagged memory ranges should be deferred, registered or > dropped. > > No functional changes. > > Signed-off-by: Smita Koralahalli > --- > drivers/dax/bus.c | 3 +++ > drivers/dax/bus.h | 8 ++++++++ > 2 files changed, 11 insertions(+) > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > index fde29e0ad68b..72bc5b76f061 100644 > --- a/drivers/dax/bus.c > +++ b/drivers/dax/bus.c > @@ -24,6 +24,9 @@ DECLARE_RWSEM(dax_region_rwsem); > */ > DECLARE_RWSEM(dax_dev_rwsem); > > +enum dax_cxl_mode dax_cxl_mode = DAX_CXL_MODE_DEFER; > +EXPORT_SYMBOL_GPL(dax_cxl_mode); > + > #define DAX_NAME_LEN 30 > struct dax_id { > struct list_head list; > diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h > index cbbf64443098..a40cbbf1e26b 100644 > --- a/drivers/dax/bus.h > +++ b/drivers/dax/bus.h > @@ -41,6 +41,14 @@ struct dax_device_driver { > void (*remove)(struct dev_dax *dev); > }; > > +enum dax_cxl_mode { I'd suggest kernel-doc for these. Their meaning isn't entirely obvious from the names. > + DAX_CXL_MODE_DEFER, > + DAX_CXL_MODE_REGISTER, > + DAX_CXL_MODE_DROP, > +}; > + > +extern enum dax_cxl_mode dax_cxl_mode; > + > int __dax_driver_register(struct dax_device_driver *dax_drv, > struct module *module, const char *mod_name); > #define dax_driver_register(driver) \