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From: Dan Williams <dan.j.williams@intel.com>
To: Ben Widawsky <ben.widawsky@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: Sun, 31 Oct 2021 11:10:23 -0700	[thread overview]
Message-ID: <CAPcyv4gpA=DH0SQvRdmF6dY01mZ1S-gGEWTSDbb+0ajYtyNv0A@mail.gmail.com> (raw)
In-Reply-To: <CAPcyv4jUDXuV-R8HFzJb1K5HK6xaGMor3JH-4AFKJqPJk9FtdA@mail.gmail.com>

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.

  reply	other threads:[~2021-10-31 18:10 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 [this message]
2021-11-01 17:36         ` Ben Widawsky
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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