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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, Ben Widawsky <ben.widawsky@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>
Subject: Re: [PATCH v3 20/28] cxl/mbox: Add exclusive kernel command support
Date: Fri, 3 Sep 2021 13:47:41 -0700	[thread overview]
Message-ID: <CAPcyv4hfHdcNpbubU6QBmbcnL8E=s8i9e54suY8GwrbfkwOniw@mail.gmail.com> (raw)
In-Reply-To: <20210902190941.0000590f@Huawei.com>

On Thu, Sep 2, 2021 at 11:09 AM Jonathan Cameron
<Jonathan.Cameron@huawei.com> wrote:
>
> On Tue, 24 Aug 2021 09:07:13 -0700
> Dan Williams <dan.j.williams@intel.com> wrote:
>
> > The CXL_PMEM driver expects exclusive control of the label storage area
> > space. Similar to the LIBNVDIMM expectation that the label storage area
> > is only writable from userspace when the corresponding memory device is
> > not active in any region, the expectation is the native CXL_PCI UAPI
> > path is disabled while the cxl_nvdimm for a given cxl_memdev device is
> > active in LIBNVDIMM.
> >
> > Add the ability to toggle the availability of a given command for the
> > UAPI path. Use that new capability to shutdown changes to partitions and
> > the label storage area while the cxl_nvdimm device is actively proxying
> > commands for LIBNVDIMM.
> >
> > Acked-by: Ben Widawsky <ben.widawsky@intel.com>
> > Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> > ---
> >  drivers/cxl/core/mbox.c   |    5 +++++
> >  drivers/cxl/core/memdev.c |   31 +++++++++++++++++++++++++++++++
> >  drivers/cxl/cxlmem.h      |    4 ++++
> >  drivers/cxl/pmem.c        |   35 ++++++++++++++++++++++++++++-------
> >  4 files changed, 68 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> > index 73107b302224..6a5c4f3679ba 100644
> > --- a/drivers/cxl/core/mbox.c
> > +++ b/drivers/cxl/core/mbox.c
> > @@ -230,6 +230,7 @@ static bool cxl_mem_raw_command_allowed(u16 opcode)
> >   *  * %-EINVAL       - Reserved fields or invalid values were used.
> >   *  * %-ENOMEM       - Input or output buffer wasn't sized properly.
> >   *  * %-EPERM        - Attempted to use a protected command.
> > + *  * %-EBUSY        - Kernel has claimed exclusive access to this opcode
> >   *
> >   * The result of this command is a fully validated command in @out_cmd that is
> >   * safe to send to the hardware.
> > @@ -305,6 +306,10 @@ static int cxl_validate_cmd_from_user(struct cxl_mem *cxlm,
> >       if (!test_bit(info->id, cxlm->enabled_cmds))
> >               return -ENOTTY;
> >
> > +     /* Check that the command is not claimed for exclusive kernel use */
> > +     if (test_bit(info->id, cxlm->exclusive_cmds))
> > +             return -EBUSY;
> > +
> >       /* Check the input buffer is the expected size */
> >       if (info->size_in >= 0 && info->size_in != send_cmd->in.size)
> >               return -ENOMEM;
>
>
> >  #endif /* __CXL_MEM_H__ */
> > diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
> > index 9652c3ee41e7..469b984176a2 100644
> > --- a/drivers/cxl/pmem.c
> > +++ b/drivers/cxl/pmem.c
> > @@ -16,9 +16,21 @@
> >   */
> >  static struct workqueue_struct *cxl_pmem_wq;
> >
> > -static void unregister_nvdimm(void *nvdimm)
> > +static __read_mostly DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX);
> > +
> > +static void unregister_nvdimm(void *_cxl_nvd)
> >  {
> > -     nvdimm_delete(nvdimm);
> > +     struct cxl_nvdimm *cxl_nvd = _cxl_nvd;
> > +     struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
> > +     struct cxl_mem *cxlm = cxlmd->cxlm;
> > +     struct device *dev = &cxl_nvd->dev;
> > +     struct nvdimm *nvdimm;
> > +
> > +     nvdimm = dev_get_drvdata(dev);
> > +     if (nvdimm)
> > +             nvdimm_delete(nvdimm);
> > +
> > +     clear_exclusive_cxl_commands(cxlm, exclusive_cmds);
> >  }
> >
> >  static int match_nvdimm_bridge(struct device *dev, const void *data)
> > @@ -39,9 +51,11 @@ static struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(void)
> >  static int cxl_nvdimm_probe(struct device *dev)
> >  {
> >       struct cxl_nvdimm *cxl_nvd = to_cxl_nvdimm(dev);
> > +     struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
> > +     struct cxl_mem *cxlm = cxlmd->cxlm;
> >       struct cxl_nvdimm_bridge *cxl_nvb;
> > +     struct nvdimm *nvdimm = NULL;
> >       unsigned long flags = 0;
> > -     struct nvdimm *nvdimm;
> >       int rc = -ENXIO;
> >
> >       cxl_nvb = cxl_find_nvdimm_bridge();
> > @@ -52,17 +66,20 @@ static int cxl_nvdimm_probe(struct device *dev)
> >       if (!cxl_nvb->nvdimm_bus)
> >               goto out;
> >
> > +     set_exclusive_cxl_commands(cxlm, exclusive_cmds);
> > +
> >       set_bit(NDD_LABELING, &flags);
> >       nvdimm = nvdimm_create(cxl_nvb->nvdimm_bus, cxl_nvd, NULL, flags, 0, 0,
> >                              NULL);
> > -     if (!nvdimm)
> > -             goto out;
> > -
> > -     rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm);
> > +     dev_set_drvdata(dev, nvdimm);
> > +     rc = devm_add_action_or_reset(dev, unregister_nvdimm, cxl_nvd);
>
> I think this ends up less readable than explicit devm handling of each part
> rather than combining them.
>
>
>         set_exclusive...()
>         rc = devm_add_action_or_rset(dev, unset_exclusive, cxlm);
>         if (rc)
>                 goto out;
>
>         nvidimm = nvdim_create()
>         if (!nvdimm) //return value looks dubious in old code but I've not checked it properly.
>                 goto out;
>
>         rc = devm_add_action_or_reset(dev, unregister_nvdimm, nvdimm);
>         if (rc)
>                 goto out;
>         dev_set_drvdata(dev, nvdimm);
>
> and two simpler unwinding functions doing just one thing each.

Taking it a step further, the unwind is so simple here, might as well
just have a typical cxl_nvdimm_remove() and drop the devm.

  reply	other threads:[~2021-09-03 20:47 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 [this message]
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

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