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Tue, 19 May 2026 23:56:30 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Tue, 19 May 2026 20:56:11 -0700 From: "Dan Williams" To: "Tomasz Wolski" , smita.koralahallichannabasappa@amd.com, "Alison Schofield" , "Dan J Williams" Cc: icheng@nvidia.com, linux-cxl@vger.kernel.org, "linux-fsdevel@vger.kernel.org" , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, nvdimm@lists.linux.dev, ardb@kernel.org, benjamin.cheatham@amd.com, "Dave Jiang" , "Jonathan Cameron" Message-Id: In-Reply-To: <20260519101832.31988-1-tomasz.wolski@fujitsu.com> References: <20260519101832.31988-1-tomasz.wolski@fujitsu.com> Subject: Re: [PATCH v2] dax/bus: Upgrade resource conflict message to dev_err() in alloc_dax_region() Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Tue, May 19, 2026, at 3:18 AM, Tomasz Wolski wrote: > The dax_region resource conflict in alloc_dax_region() indicates a > serious configuration problem =E2=80=94 two subsystems (e.g. dax_hmem = and > dax_cxl) are attempting to register overlapping address ranges. This is > not a transient or debug-level condition; it represents a genuine > resource conflict that an administrator needs to be aware of. > > Switch from request_resource() + dev_dbg() to > request_resource_conflict() + dev_err() so that the conflict is visible > by default and the colliding resource is identified in the message. > > Suggested-by: Dan Williams > Link:=20 > https://lore.kernel.org/linux-cxl/69c1a8d1c0fa9_7ee3100a1@dwillia2-mob= l4.notmuch/ > Signed-off-by: Tomasz Wolski > --- > drivers/dax/bus.c | 11 ++++++----- > 1 file changed, 6 insertions(+), 5 deletions(-) > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > index 68437c05e21d..66413c6c2ba0 100644 > --- a/drivers/dax/bus.c > +++ b/drivers/dax/bus.c > @@ -637,7 +637,7 @@ struct dax_region *alloc_dax_region(struct device=20 > *parent, int region_id, > unsigned long flags) > { > struct dax_region *dax_region; > - int rc; > + struct resource *conflict; >=20 > /* > * The DAX core assumes that it can store its private data in > @@ -670,10 +670,11 @@ struct dax_region *alloc_dax_region(struct devic= e=20 > *parent, int region_id, > .flags =3D IORESOURCE_MEM | flags, > }; >=20 > - rc =3D request_resource(&dax_regions, &dax_region->res); > - if (rc) { > - dev_dbg(parent, "dax_region resource conflict for %pR\n", > - &dax_region->res); > + conflict =3D request_resource_conflict(&dax_regions, &dax_region->re= s); Just report the request_resource() failure. This case does not warrant e= xporting request_resource _conflict(). Historically one driver can not m= ess with another driver's resource beyond conflict detection.