linux-kernel - Re: [PATCH v3] acpi: configfs: Unload SSDT on configfs entry removal

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Date:   Tue, 4 Jul 2017 14:08:33 +0200
From:   Jan Kiszka <jan.kiszka@...mens.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>, Lv Zheng <lv.zheng@...el.com>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "devel@...ica.org" <devel@...ica.org>,
        "Moore, Robert" <robert.moore@...el.com>
Subject: Re: [PATCH v3] acpi: configfs: Unload SSDT on configfs entry removal

On 2017-07-04 14:05, Rafael J. Wysocki wrote:
> On Tue, Jul 4, 2017 at 8:14 AM, Jan Kiszka <jan.kiszka@...mens.com> wrote:
>> On 2017-06-09 20:36, Jan Kiszka wrote:
>>> Call directly into acpica to load a table to obtain its index on return.
>>> We choose the direct call of acpica internal functions to avoid having
>>> to modify its API which is used outside of Linux as well.
>>>
>>> Use that index to unload the table again when the corresponding
>>> directory in configfs gets removed. This allows to change SSDTs without
>>> rebooting the system. It also allows to destroy devices again that a
>>> dynamically loaded SSDT created.
>>>
>>> This is widely similar to the DT overlay behavior.
>>>
>>> Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
>>> ---
>>>
>>> Change in v3:
>>>  - fix breakage if acpi_configfs is modular
>>>
>>>  drivers/acpi/acpi_configfs.c | 20 +++++++++++++++++++-
>>>  drivers/acpi/acpica/tbdata.c |  4 ++++
>>>  2 files changed, 23 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
>>> index 146a77fb762d..853bc7fc673f 100644
>>> --- a/drivers/acpi/acpi_configfs.c
>>> +++ b/drivers/acpi/acpi_configfs.c
>>> @@ -15,11 +15,15 @@
>>>  #include <linux/configfs.h>
>>>  #include <linux/acpi.h>
>>>
>>> +#include "acpica/accommon.h"
>>> +#include "acpica/actables.h"
>>> +
>>>  static struct config_group *acpi_table_group;
>>>
>>>  struct acpi_table {
>>>       struct config_item cfg;
>>>       struct acpi_table_header *header;
>>> +     u32 index;
>>>  };
>>>
>>>  static ssize_t acpi_table_aml_write(struct config_item *cfg,
>>> @@ -52,7 +56,11 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
>>>       if (!table->header)
>>>               return -ENOMEM;
>>>
>>> -     ret = acpi_load_table(table->header);
>>> +     ACPI_INFO(("Host-directed Dynamic ACPI Table Load:"));
>>> +     ret = acpi_tb_install_and_load_table(
>>> +                     ACPI_PTR_TO_PHYSADDR(table->header),
>>> +                     ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL, FALSE,
>>> +                     &table->index);
>>>       if (ret) {
>>>               kfree(table->header);
>>>               table->header = NULL;
>>> @@ -215,8 +223,18 @@ static struct config_item *acpi_table_make_item(struct config_group *group,
>>>       return &table->cfg;
>>>  }
>>>
>>> +static void acpi_table_drop_item(struct config_group *group,
>>> +                              struct config_item *cfg)
>>> +{
>>> +     struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
>>> +
>>> +     ACPI_INFO(("Host-directed Dynamic ACPI Table Unload"));
>>> +     acpi_tb_unload_table(table->index);
>>> +}
>>> +
>>>  struct configfs_group_operations acpi_table_group_ops = {
>>>       .make_item = acpi_table_make_item,
>>> +     .drop_item = acpi_table_drop_item,
>>>  };
>>>
>>>  static struct config_item_type acpi_tables_type = {
>>> diff --git a/drivers/acpi/acpica/tbdata.c b/drivers/acpi/acpica/tbdata.c
>>> index 27c5c27d4818..c9d6fa6d7cc6 100644
>>> --- a/drivers/acpi/acpica/tbdata.c
>>> +++ b/drivers/acpi/acpica/tbdata.c
>>> @@ -867,6 +867,8 @@ acpi_tb_install_and_load_table(acpi_physical_address address,
>>>       return_ACPI_STATUS(status);
>>>  }
>>>
>>> +ACPI_EXPORT_SYMBOL(acpi_tb_install_and_load_table)
>>> +
>>>  /*******************************************************************************
>>>   *
>>>   * FUNCTION:    acpi_tb_unload_table
>>> @@ -914,3 +916,5 @@ acpi_status acpi_tb_unload_table(u32 table_index)
>>>       acpi_tb_set_table_loaded_flag(table_index, FALSE);
>>>       return_ACPI_STATUS(status);
>>>  }
>>> +
>>> +ACPI_EXPORT_SYMBOL(acpi_tb_unload_table)
>>>
>>
>> Ping for this patch.
> 
> Pushed to Linus and is waiting for merging (along with the other ACPI
> changes for 4.13).
> 

Ah, perfect - seems I didn't receive any notification.

Thanks,
Jan

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