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From: Dan Williams <dan.j.williams@intel.com>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: linux-cxl@vger.kernel.org, kernel test robot <lkp@intel.com>,
	 Vishal L Verma <vishal.l.verma@intel.com>,
	"Schofield, Alison" <alison.schofield@intel.com>,
	 Linux NVDIMM <nvdimm@lists.linux.dev>,
	"Weiny, Ira" <ira.weiny@intel.com>,
	 Ben Widawsky <ben.widawsky@intel.com>
Subject: Re: [PATCH v3 28/28] cxl/core: Split decoder setup into alloc + add
Date: Fri, 3 Sep 2021 17:27:12 -0700	[thread overview]
Message-ID: <CAPcyv4hTHq6BRek_5bMn0jbz2bQ=8Kd6EaBjsc6s2=snY5ws5g@mail.gmail.com> (raw)
In-Reply-To: <20210903190133.000003e2@Huawei.com>

On Fri, Sep 3, 2021 at 11:01 AM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> On Fri, 3 Sep 2021 09:26:09 -0700
> Dan Williams <dan.j.williams@intel.com> wrote:
>
> > On Fri, Sep 3, 2021 at 6:34 AM Jonathan Cameron
> > <Jonathan.Cameron@huawei.com> wrote:
> > >
> > > On Tue, 24 Aug 2021 09:07:56 -0700
> > > Dan Williams <dan.j.williams@intel.com> wrote:
> > >
> > > > The kbuild robot reports:
> > > >
> > > >     drivers/cxl/core/bus.c:516:1: warning: stack frame size (1032) exceeds
> > > >     limit (1024) in function 'devm_cxl_add_decoder'
> > > >
> > > > It is also the case the devm_cxl_add_decoder() is unwieldy to use for
> > > > all the different decoder types. Fix the stack usage by splitting the
> > > > creation into alloc and add steps. This also allows for context
> > > > specific construction before adding.
> > > >
> > > > Reported-by: kernel test robot <lkp@intel.com>
> > > > Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> > >
> > > Trivial comment inline - otherwise looks like a nice improvement.
> > >
> > > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> >
> > >
> > > > ---
> > > >  drivers/cxl/acpi.c     |   74 ++++++++++++++++++++---------
> > > >  drivers/cxl/core/bus.c |  124 +++++++++++++++---------------------------------
> > > >  drivers/cxl/cxl.h      |   15 ++----
> > > >  3 files changed, 95 insertions(+), 118 deletions(-)
> > > >
> > >
> > > > @@ -268,6 +275,7 @@ static int add_host_bridge_uport(struct device *match, void *arg)
> > > >       struct cxl_port *port;
> > > >       struct cxl_dport *dport;
> > > >       struct cxl_decoder *cxld;
> > > > +     int single_port_map[1], rc;
> > > >       struct cxl_walk_context ctx;
> > > >       struct acpi_pci_root *pci_root;
> > > >       struct cxl_port *root_port = arg;
> > > > @@ -301,22 +309,42 @@ static int add_host_bridge_uport(struct device *match, void *arg)
> > > >               return -ENODEV;
> > > >       if (ctx.error)
> > > >               return ctx.error;
> > > > +     if (ctx.count > 1)
> > > > +             return 0;
> > > >
> > > >       /* TODO: Scan CHBCR for HDM Decoder resources */
> > > >
> > > >       /*
> > > > -      * In the single-port host-bridge case there are no HDM decoders
> > > > -      * in the CHBCR and a 1:1 passthrough decode is implied.
> > > > +      * Per the CXL specification (8.2.5.12 CXL HDM Decoder Capability
> > > > +      * Structure) single ported host-bridges need not publish a decoder
> > > > +      * capability when a passthrough decode can be assumed, i.e. all
> > > > +      * transactions that the uport sees are claimed and passed to the single
> > > > +      * dport. Default the range a 0-base 0-length until the first CXL region
> > > > +      * is activated.
> > > >        */
> > >
> > > Is comment in right place or should it be up with the ctx.count > 1
> >
> > This comment is specifically about the implicit decoder, right beneath
> > the comment, that is registered in the ctx.count == 1 case. Perhaps
> > you were reacting to the spec reference which is generic, but later
> > sentences make it clear this comment is about an exception noted in
> > that spec reference?
>
> More that the conditional is above that leads to us getting here.
> Probably thrown off by Diff having added the new block that follows this
> after the removed block rather than before it.
>
> I'm fine with how you have it here.
>

Thanks, although I am going to leave your reviewed-by off for now
because I am going to fold this with this fixup patch that arrived
later which makes some significant changes:

https://lore.kernel.org/r/163002073312.1700305.17017280228713298614.stgit@dwillia2-desk3.amr.corp.intel.com

      reply	other threads:[~2021-09-04  0:27 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-24 16:05 [PATCH v3 00/28] cxl_test: Enable CXL Topology and UAPI regression tests Dan Williams
2021-08-24 16:05 ` [PATCH v3 01/28] libnvdimm/labels: Introduce getters for namespace label fields Dan Williams
2021-08-24 16:05 ` [PATCH v3 02/28] libnvdimm/labels: Add isetcookie validation helper Dan Williams
2021-08-24 16:05 ` [PATCH v3 03/28] libnvdimm/labels: Introduce label setter helpers Dan Williams
2021-08-24 16:05 ` [PATCH v3 04/28] libnvdimm/labels: Add a checksum calculation helper Dan Williams
2021-08-24 16:05 ` [PATCH v3 05/28] libnvdimm/labels: Add blk isetcookie set / validation helpers Dan Williams
2021-08-24 16:05 ` [PATCH v3 06/28] libnvdimm/labels: Add blk special cases for nlabel and position helpers Dan Williams
2021-08-24 16:06 ` [PATCH v3 07/28] libnvdimm/labels: Add type-guid helpers Dan Williams
2021-08-24 16:06 ` [PATCH v3 08/28] libnvdimm/labels: Add claim class helpers Dan Williams
2021-08-24 16:06 ` [PATCH v3 09/28] libnvdimm/labels: Add address-abstraction uuid definitions Dan Williams
2021-08-24 16:06 ` [PATCH v3 10/28] libnvdimm/labels: Add uuid helpers Dan Williams
2021-08-24 16:06 ` [PATCH v3 11/28] libnvdimm/label: Add a helper for nlabel validation Dan Williams
2021-09-02 16:37   ` Jonathan Cameron
2021-08-24 16:06 ` [PATCH v3 12/28] libnvdimm/labels: Introduce the concept of multi-range namespace labels Dan Williams
2021-09-02 16:43   ` Jonathan Cameron
2021-08-24 16:06 ` [PATCH v3 13/28] libnvdimm/label: Define CXL region labels Dan Williams
2021-09-02 16:36   ` Jonathan Cameron
2021-09-02 16:41     ` Jonathan Cameron
2021-09-03  3:58       ` Dan Williams
2021-08-24 16:06 ` [PATCH v3 14/28] libnvdimm/labels: Introduce CXL labels Dan Williams
2021-09-03 17:00   ` Dan Williams
2021-08-24 16:06 ` [PATCH v3 15/28] cxl/pci: Make 'struct cxl_mem' device type generic Dan Williams
2021-09-02 16:55   ` Jonathan Cameron
2021-09-02 17:34     ` Dan Williams
2021-08-24 16:06 ` [PATCH v3 16/28] cxl/mbox: Introduce the mbox_send operation Dan Williams
2021-09-02 17:07   ` Jonathan Cameron
2021-08-24 16:06 ` [PATCH v3 17/28] cxl/mbox: Move mailbox and other non-PCI specific infrastructure to the core Dan Williams
2021-09-02 17:56   ` Jonathan Cameron
2021-09-02 18:56     ` Dan Williams
2021-08-24 16:07 ` [PATCH v3 18/28] cxl/pci: Use module_pci_driver Dan Williams
2021-09-02 17:58   ` Jonathan Cameron
2021-08-24 16:07 ` [PATCH v3 19/28] cxl/mbox: Convert 'enabled_cmds' to DECLARE_BITMAP Dan Williams
2021-09-02 17:59   ` Jonathan Cameron
2021-08-24 16:07 ` [PATCH v3 20/28] cxl/mbox: Add exclusive kernel command support Dan Williams
2021-09-02 18:09   ` Jonathan Cameron
2021-09-03 20:47     ` Dan Williams
2021-08-24 16:07 ` [PATCH v3 21/28] cxl/pmem: Translate NVDIMM label commands to CXL label commands Dan Williams
2021-09-02 18:22   ` Jonathan Cameron
2021-09-03 21:09     ` Dan Williams
2021-08-24 16:07 ` [PATCH v3 22/28] cxl/pmem: Add support for multiple nvdimm-bridge objects Dan Williams
2021-09-03 11:15   ` Jonathan Cameron
2021-08-24 16:07 ` [PATCH v3 23/28] cxl/acpi: Do not add DSDT disabled ACPI0016 host bridge ports Dan Williams
2021-09-02 18:30   ` Jonathan Cameron
2021-09-03 17:51     ` Dan Williams
2021-08-24 16:07 ` [PATCH v3 24/28] tools/testing/cxl: Introduce a mocked-up CXL port hierarchy Dan Williams
2021-09-03 12:52   ` Jonathan Cameron
2021-09-03 21:49     ` Dan Williams
2021-09-06  8:32       ` Jonathan Cameron
2021-09-07 15:57         ` Dan Williams
2021-08-24 16:07 ` [PATCH v3 25/28] cxl/bus: Populate the target list at decoder create Dan Williams
2021-09-03 12:59   ` Jonathan Cameron
2021-09-03 22:43     ` Dan Williams
2021-09-06  8:52       ` Jonathan Cameron
2021-08-24 16:07 ` [PATCH v3 26/28] cxl/mbox: Move command definitions to common location Dan Williams
2021-09-03 13:04   ` Jonathan Cameron
2021-08-24 16:07 ` [PATCH v3 27/28] tools/testing/cxl: Introduce a mock memory device + driver Dan Williams
2021-09-03 13:21   ` Jonathan Cameron
2021-09-03 23:33     ` Dan Williams
2021-09-06  8:57       ` Jonathan Cameron
2021-08-24 16:07 ` [PATCH v3 28/28] cxl/core: Split decoder setup into alloc + add Dan Williams
2021-09-03 13:33   ` Jonathan Cameron
2021-09-03 16:26     ` Dan Williams
2021-09-03 18:01       ` Jonathan Cameron
2021-09-04  0:27         ` Dan Williams [this message]

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