Re: [PATCH] ACPICA: make acpi_load_table() return table index

[Nikolaus Voss]

On Thu, 19 Sep 2019, Rafael J. Wysocki wrote:
> On Thursday, September 12, 2019 10:07:42 AM CEST Nikolaus Voss wrote:
> > For unloading an ACPI table, it is necessary to provide the
> > index of the table. The method intended for dynamically
> > loading or hotplug addition of tables, acpi_load_table(),
> > should provide this information via an optional pointer
> > to the loaded table index.
> >
> > This patch fixes the table unload function of acpi_configfs.
> >
> > Reported-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
> > Signed-off-by: Nikolaus Voss <nikolaus.voss@xxxxxxxxxxxxxxxxxxxxx>
>
> Overall, I think that something similar to this patch will be needed, but
> please don't change the acpi_load_table() signature.  Instead, define it as
> a wrapper around a new function called, say, acpi_load_table_with_index()
> that will take two arguments, like acpi_load_table() in your patch.
>
> Then, you'd only need to call acpi_load_table_with_index() directly from
> acpi_table_aml_write().
>
> In that case, IMO, it will be easier to handle the divergence between the
> upstream ACPICA and the kernel in the future in case the upstream doesn't
> decide to incorporate your change.

Ok, I'll prepare a patch.

> > ---
> >  drivers/acpi/acpi_configfs.c   | 2 +-
> >  drivers/acpi/acpica/dbfileio.c | 2 +-
> >  drivers/acpi/acpica/tbxfload.c | 8 ++++++--
> >  drivers/firmware/efi/efi.c     | 2 +-
> >  include/acpi/acpixf.h          | 3 ++-
> >  5 files changed, 11 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
> > index 57d9d574d4dde..77f81242a28e6 100644
> > --- a/drivers/acpi/acpi_configfs.c
> > +++ b/drivers/acpi/acpi_configfs.c
> > @@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
> >  	if (!table->header)
> >  		return -ENOMEM;
> >
> > -	ret = acpi_load_table(table->header);
> > +	ret = acpi_load_table(table->header, &table->index);
> >  	if (ret) {
> >  		kfree(table->header);
> >  		table->header = NULL;
> > diff --git a/drivers/acpi/acpica/dbfileio.c b/drivers/acpi/acpica/dbfileio.c
> > index c6e25734dc5cd..e1b6e54a96ac1 100644
> > --- a/drivers/acpi/acpica/dbfileio.c
> > +++ b/drivers/acpi/acpica/dbfileio.c
> > @@ -93,7 +93,7 @@ acpi_status acpi_db_load_tables(struct acpi_new_table_desc *list_head)
> >  	while (table_list_head) {
> >  		table = table_list_head->table;
> >
> > -		status = acpi_load_table(table);
> > +		status = acpi_load_table(table, NULL);
> >  		if (ACPI_FAILURE(status)) {
> >  			if (status == AE_ALREADY_EXISTS) {
> >  				acpi_os_printf
> > diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c
> > index 86f1693f6d29a..d08cd8ffcbdb6 100644
> > --- a/drivers/acpi/acpica/tbxfload.c
> > +++ b/drivers/acpi/acpica/tbxfload.c
> > @@ -268,7 +268,8 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
> >   *
> >   * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
> >   *                                    table to be loaded.
> > - *
> > + *              table_idx           - Pointer to a u32 for storing the table
> > + *                                    index, might be NULL
> >   * RETURN:      Status
> >   *
> >   * DESCRIPTION: Dynamically load an ACPI table from the caller's buffer. Must
> > @@ -278,7 +279,7 @@ ACPI_EXPORT_SYMBOL_INIT(acpi_install_table)
> >   *              to ensure that the table is not deleted or unmapped.
> >   *
> >   ******************************************************************************/
> > -acpi_status acpi_load_table(struct acpi_table_header *table)
> > +acpi_status acpi_load_table(struct acpi_table_header *table, u32 *table_idx)
> >  {
> >  	acpi_status status;
> >  	u32 table_index;
> > @@ -297,6 +298,9 @@ acpi_status acpi_load_table(struct acpi_table_header *table)
> >  	status = acpi_tb_install_and_load_table(ACPI_PTR_TO_PHYSADDR(table),
> >  						ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
> >  						FALSE, &table_index);
> > +	if (table_idx)
> > +		*table_idx = table_index;
> > +
> >  	if (ACPI_SUCCESS(status)) {
> >
> >  		/* Complete the initialization/resolution of new objects */
> > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> > index ad3b1f4866b35..9773e4212baef 100644
> > --- a/drivers/firmware/efi/efi.c
> > +++ b/drivers/firmware/efi/efi.c
> > @@ -308,7 +308,7 @@ static __init int efivar_ssdt_load(void)
> >  			goto free_data;
> >  		}
> >
> > -		ret = acpi_load_table(data);
> > +		ret = acpi_load_table(data, NULL);
> >  		if (ret) {
> >  			pr_err("failed to load table: %d\n", ret);
> >  			goto free_data;
> > diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
> > index 3845c8fcc94e5..c90bbdc4146a6 100644
> > --- a/include/acpi/acpixf.h
> > +++ b/include/acpi/acpixf.h
> > @@ -452,7 +452,8 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
> >  					       u8 physical))
> >
> >  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> > -			    acpi_load_table(struct acpi_table_header *table))
> > +			    acpi_load_table(struct acpi_table_header *table,
> > +					    u32 *table_idx))
> >
> >  ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> >  			    acpi_unload_parent_table(acpi_handle object))