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Mon, 2 Feb 2026 17:54:19 +0000 Date: Mon, 2 Feb 2026 17:54:17 +0000 From: Jonathan Cameron To: Gregory Price CC: , , , , , , , , , , , , , , , , Subject: Re: [PATCH 4/9] drivers/cxl,dax: add dax driver mode selection for dax regions Message-ID: <20260202175417.00000abe@huawei.com> In-Reply-To: <20260129210442.3951412-5-gourry@gourry.net> References: <20260129210442.3951412-1-gourry@gourry.net> <20260129210442.3951412-5-gourry@gourry.net> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.203.177.15] X-ClientProxiedBy: lhrpeml100009.china.huawei.com (7.191.174.83) To dubpeml500005.china.huawei.com (7.214.145.207) X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 4595210000B X-Stat-Signature: fysz11641tc5xy44y8dwbnbogwqgiuhm X-HE-Tag: 1770054865-833824 X-HE-Meta: U2FsdGVkX1/B1aC6jA3O4YLapzxRMHcgByDWhKe3c+CXwTKtaCuwgSzStFe5NRy9vLDhuWNCL/w2llM9BUgwvnvI+YPdH1dfGBhexcQVSUB4PicShuQ4Zu7CgSeofh4YcUjOiKRcPrJ/YnJVQClfV/HhS6Jqx3xVkFgJmpF/7KaZcDb6RSPhjbgDgjlDo/M+XaGBPBwm0O4Rs5zuN9+uebskEmpt1I4fS44h9nf9DtoJD0kgKFKSiosONJgNgT9l22XFoNex/3ALKA/E90HstRxVFlC7zZCDY1TwGNQICY0vpDqjt5Nz1KMpOoKogu5VUOOagKx8Q2Wj4bSqbqi5jylnSDYQ92dDm9YcpxCOfQzMGqm6TeqR9hP2JPL7bVWK16Uv8aYR106X5QlTKj++5DEYDSxuTbV78/UaNa5wHmnanezbdXvT3LZqhpouejyQjLpKZO8rBDxvb1OaJ2czNjW8nbo1wk0HW/CG5IPKsi+DArl8W+WUcEKU5z7qKHdal6Cc45rZtenNOXK8SIzMFPPxnSYIwtO2mGKNXE9D4GBWFL3s2IuEe+QNMnc1mJEdN1nCFHeoei1WOfWxWf1he9Oyb4565yRhVb2d4pjsfpOKyYZbxtkOsrhACpeZ88VRBrptgsEqL+KgHRpa3qbXP/WbQD/xwQFJNJtbbtcqfgAh+ayljFgrSdPLCHgD7Hy5J2/Tk3WNU3QclMq2iEu69geBpru5uzrDb/A0NXSuQZcnzkOVOSU4LBFLSvqW60zCue3lXLrH1GsMRUJxOwUMtcv8toEqjPAS41gSPK+vjpLuMTu5Sv/3gbTtS0jyyujoeBQ5FUKt0Ovh5mJF8lq1XeB1VNhwYd0IRCcaoaQq0Nar0pw5j3nbVFaZ3/RMxmxubhTJB4aL5UKreY6RuM9qtVYchmZ01YcTfy5pDQx4vR/oHD9neyEr0Eghw+zpOn5tAZUBuFwsT2J2ESpZ7oM OeRrEfP7 gtAhf3gIuIAtgi9fjGJ1rkqoTSO7NJK5Y/a4a7/lM+8k+y4HwbNR+qFfAjhvNfzyPYd6wVdHrq+9+8VZpjh3zqBbLJkkGqcLRjJkctKRWZOQcXfI3FFBMm15RAHWL/XljwbFvdatCLDQpd+FIzTmbkorRsi4g0epE5ui6Geju5OZM13CN8wRS9RW8UibJkxkadbJR9NZ85BmH8LwuJQd5Y3RVI7Tkju6s5ypgOSYScV6xGmKL6Hk7slbAgtBWwneukTULzSLfdv3A0uHLImUlX/3sN7XBBp+8NNW5mJ3t7w0f16uB/gNvNPX4lKYk+mEqWyFwWhaG2+KxF5toAIyhl3z96HcObDf+4oWO6dmmArfu5pY= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 29 Jan 2026 16:04:37 -0500 Gregory Price wrote: > CXL regions may wish not to auto-configure their memory as dax kmem, > but the current plumbing defaults all cxl-created dax devices to the > kmem driver. This exposes them to hotplug policy, even if the user > intends to use the memory as a dax device. > > Add plumbing to allow CXL drivers to select whether a DAX region should > default to kmem (DAXDRV_KMEM_TYPE) or device (DAXDRV_DEVICE_TYPE). > > Add a 'dax_driver' field to struct cxl_dax_region and update > devm_cxl_add_dax_region() to take a dax_driver_type parameter. > > In drivers/dax/cxl.c, the IORESOURCE_DAX_KMEM flag used by dax driver > matching code is now set conditionally based on dax_region->dax_driver. > > Exports `enum dax_driver_type` to linux/dax.h for use in the cxl driver. > > All current callers pass DAXDRV_KMEM_TYPE for backward compatibility. > > Cc: John Groves > Signed-off-by: Gregory Price LGTM Reviewed-by: Jonathan Cameron