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From: Ben Widawsky <ben.widawsky@intel.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-cxl@vger.kernel.org,
	Chet Douglas <chet.r.douglas@intel.com>,
	Alison Schofield <alison.schofield@intel.com>,
	Ira Weiny <ira.weiny@intel.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Vishal Verma <vishal.l.verma@intel.com>
Subject: Re: [RFC PATCH v2 08/28] cxl/port: Introduce a port driver
Date: Mon, 1 Nov 2021 10:36:21 -0700	[thread overview]
Message-ID: <20211101173621.rylmmmlw3uttskak@intel.com> (raw)
In-Reply-To: <CAPcyv4gpA=DH0SQvRdmF6dY01mZ1S-gGEWTSDbb+0ajYtyNv0A@mail.gmail.com>

On 21-10-31 11:10:23, Dan Williams wrote:
> On Sun, Oct 31, 2021 at 10:53 AM Dan Williams <dan.j.williams@intel.com> wrote:
> >
> > On Fri, Oct 29, 2021 at 6:37 PM Dan Williams <dan.j.williams@intel.com> wrote:
> > [..]
> > >
> > > Proposed infrastructure for a new cxl_port_decoder_autoremove():
> > >
> > > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> > > index 3163167ecc3a..78f8313a1069 100644
> > > --- a/drivers/cxl/acpi.c
> > > +++ b/drivers/cxl/acpi.c
> > > @@ -374,6 +374,11 @@ static int add_root_nvdimm_bridge(struct device
> > > *match, void *data)
> > >         return 1;
> > >  }
> > >
> > > +static void clear_cxl_topology_host(void *data)
> > > +{
> > > +       set_cxl_topology_host(NULL);
> > > +}
> > > +
> > >  static int cxl_acpi_probe(struct platform_device *pdev)
> > >  {
> > >         int rc;
> > > @@ -382,6 +387,11 @@ static int cxl_acpi_probe(struct platform_device *pdev)
> > >         struct acpi_device *adev = ACPI_COMPANION(host);
> > >         struct cxl_cfmws_context ctx;
> > >
> > > +       set_cxl_topology_host(host);
> > > +       rc = devm_add_action_or_reset(host, clear_cxl_topology_host, host);
> > > +       if (rc)
> > > +               return rc;
> > > +
> > >         root_port = devm_cxl_add_port(host, host, CXL_RESOURCE_NONE, NULL);
> > >         if (IS_ERR(root_port))
> > >                 return PTR_ERR(root_port);
> > > diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c
> > > index 17a4fff029f8..3146b6aa0a2f 100644
> > > --- a/drivers/cxl/core/bus.c
> > > +++ b/drivers/cxl/core/bus.c
> > > @@ -3,6 +3,7 @@
> > >  #include <linux/io-64-nonatomic-lo-hi.h>
> > >  #include <linux/device.h>
> > >  #include <linux/module.h>
> > > +#include <linux/rwsem.h>
> > >  #include <linux/pci.h>
> > >  #include <linux/slab.h>
> > >  #include <linux/idr.h>
> > > @@ -563,6 +564,84 @@ int cxl_decoder_autoremove(struct device *host,
> > > struct cxl_decoder *cxld)
> > >  }
> > >  EXPORT_SYMBOL_NS_GPL(cxl_decoder_autoremove, CXL);
> > >
> > > +void trigger_decoder_autoremove(void *data)
> > > +{
> > > +       struct cxl_decoder *cxld = data;
> > > +       struct device *host = get_cxl_topology_host();
> > > +
> > > +       /* The topology host driver beat us to the punch */
> > > +       if (!host)
> > > +               return;
> >
> > This can be dropped or turned into a WARN_ON() because something is
> > wrong if the port removal is being triggered after the topology host
> > has already went away.
> 
> It further occurs to me that if all ports are guaranteed to be torn
> down by topology host removal, then we might not even need to play
> these games at all. cxl_acpi is already unregistering all of its child
> ports, we just need the property that if a port adds a child port it
> remove it. Then I don't think we even need cxl_topology_host games.

I think having a handle to the "topology_host" is still valuable since I used it
to do the CFMWS lookup. Perhaps you have a different solution for that and I'll
see it later.

Is the suggestion here to have unregister_port() be responsible for doing an
unregister_dev for all children that are ports, or do you mean something else?

  reply	other threads:[~2021-11-01 17:37 UTC|newest]

Thread overview: 112+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-22 18:36 [RFC PATCH v2 00/28] CXL Region Creation / HDM decoder programming Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 01/28] cxl: Rename CXL_MEM to CXL_PCI Ben Widawsky
2021-10-29 20:15   ` Dan Williams
2021-10-29 21:20     ` Ben Widawsky
2021-10-29 21:39       ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 02/28] cxl: Move register block enumeration to core Ben Widawsky
2021-10-29 20:23   ` Dan Williams
2021-10-29 21:23     ` Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 03/28] cxl/acpi: Map component registers for Root Ports Ben Widawsky
2021-10-29 20:28   ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 04/28] cxl: Add helper for new drivers Ben Widawsky
2021-10-29 20:30   ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 05/28] cxl/core: Convert decoder range to resource Ben Widawsky
2021-10-29 20:50   ` Dan Williams
2021-10-29 21:26     ` Ben Widawsky
2021-10-29 22:22       ` Dan Williams
2021-10-29 22:37         ` Ben Widawsky
2021-11-01 14:33           ` Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 06/28] cxl: Introduce endpoint decoders Ben Widawsky
2021-10-29 21:00   ` Dan Williams
2021-10-29 22:02     ` Ben Widawsky
2021-10-29 22:25       ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 07/28] cxl/core: Move target population locking to caller Ben Widawsky
2021-10-29 23:03   ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 08/28] cxl/port: Introduce a port driver Ben Widawsky
2021-10-30  1:37   ` Dan Williams
2021-10-31 17:53     ` Dan Williams
2021-10-31 18:10       ` Dan Williams
2021-11-01 17:36         ` Ben Widawsky [this message]
2021-11-01 17:53     ` Ben Widawsky
2021-11-01 17:54       ` Ben Widawsky
2021-11-02  3:31       ` Dan Williams
2021-11-02 16:27         ` Ben Widawsky
2021-11-02 17:21           ` Dan Williams
2021-11-02 16:58         ` Ben Widawsky
2021-11-04 19:10           ` Dan Williams
2021-11-04 19:49             ` Ben Widawsky
2021-11-04 20:04               ` Dan Williams
2021-11-04 21:25                 ` Ben Widawsky
2021-11-04 16:37     ` Ben Widawsky
2021-11-04 19:17       ` Dan Williams
2021-11-04 19:46         ` Ben Widawsky
2021-11-04 20:00           ` Dan Williams
2021-11-04 21:26             ` Ben Widawsky
2021-11-03 15:18   ` Jonathan Cameron
2021-10-22 18:36 ` [RFC PATCH v2 09/28] cxl/acpi: Map single port host bridge component registers Ben Widawsky
2021-10-31 18:03   ` Dan Williams
2021-11-01 17:07     ` Ben Widawsky
2021-11-02  2:15       ` Dan Williams
2021-11-02 16:31         ` Ben Widawsky
2021-11-02 17:46           ` Dan Williams
2021-11-02 17:57             ` Ben Widawsky
2021-11-02 18:10               ` Dan Williams
2021-11-02 18:27                 ` Ben Widawsky
2021-11-02 18:49                   ` Dan Williams
2021-11-02 21:15                     ` Ben Widawsky
2021-11-02 21:34                       ` Dan Williams
2021-11-02 21:47                         ` Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 10/28] cxl/core: Store global list of root ports Ben Widawsky
2021-10-31 18:32   ` Dan Williams
2021-11-01 18:43     ` Ben Widawsky
2021-11-02  2:04       ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 11/28] cxl/acpi: Rescan bus at probe completion Ben Widawsky
2021-10-31 19:25   ` Dan Williams
2021-11-01 18:56     ` Ben Widawsky
2021-11-01 21:45       ` Ben Widawsky
2021-11-02  1:56         ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 12/28] cxl/core: Store component register base for memdevs Ben Widawsky
2021-10-31 20:13   ` Dan Williams
2021-11-01 21:50     ` Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 13/28] cxl: Flesh out register names Ben Widawsky
2021-10-31 20:18   ` Dan Williams
2021-11-01 22:00     ` Ben Widawsky
2021-11-02  1:53       ` Dan Williams
2021-11-03 15:53   ` Jonathan Cameron
2021-11-03 16:03     ` Ben Widawsky
2021-11-03 16:42       ` Jonathan Cameron
2021-11-03 17:05         ` Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 14/28] cxl: Hide devm host for ports Ben Widawsky
2021-10-31 21:14   ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 15/28] cxl/core: Introduce API to scan switch ports Ben Widawsky
2021-11-01  5:39   ` Dan Williams
2021-11-01 22:56     ` Ben Widawsky
2021-11-02  1:45       ` Dan Williams
2021-11-02 16:39         ` Ben Widawsky
2021-11-02 20:00           ` Dan Williams
2021-11-16 16:50         ` Ben Widawsky
2021-11-16 17:51           ` Dan Williams
2021-11-16 18:02             ` Ben Widawsky
2021-11-03 16:08   ` Jonathan Cameron
2021-11-10 17:49     ` Ben Widawsky
2021-11-10 18:10       ` Jonathan Cameron
2021-11-10 21:03         ` Dan Williams
2021-10-22 18:36 ` [RFC PATCH v2 16/28] cxl: Introduce cxl_mem driver Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 17/28] cxl: Disable switch hierarchies for now Ben Widawsky
2021-10-22 18:36 ` [RFC PATCH v2 18/28] cxl/region: Add region creation ABI Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 19/28] cxl/region: Introduce concept of region configuration Ben Widawsky
2021-12-15 17:47   ` Jonathan Cameron
2021-10-22 18:37 ` [RFC PATCH v2 20/28] cxl/region: Introduce a cxl_region driver Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 21/28] cxl/acpi: Handle address space allocation Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 22/28] cxl/region: Address " Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 23/28] cxl/region: Implement XHB verification Ben Widawsky
2022-01-06 16:55   ` Jonathan Cameron
2022-01-06 16:58     ` Ben Widawsky
2022-01-06 17:33       ` Jonathan Cameron
2022-01-06 18:10         ` Jonathan Cameron
2022-01-06 18:34           ` Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 24/28] cxl/region: HB port config verification Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 25/28] cxl/region: Record host bridge target list Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 26/28] cxl/mem: Store the endpoint's uport Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 27/28] cxl/region: Gather HDM decoder resources Ben Widawsky
2021-10-22 18:37 ` [RFC PATCH v2 28/28] cxl: Program decoders for regions Ben Widawsky

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