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SubjectRe: [PATCH] acpi: Corrections of unchecked calls to request_region
Date
On Monday, February 28, 2011, Johan Wessfeldt wrote:
> This patch introduces checks when acpi osl reserves resources by calling
> request_region.

Why is the patch necessary?

> Please review:
> Is it valid to return early when acpi_request_region() fails?

What do you mean by "return early"?

Rafael


> Signed-off-by: Johan Wessfeldt <johan.wessfeldt@gmail.com>
> ---
> drivers/acpi/osl.c | 85 +++++++++++++++++++++++++++++++++++-----------------
> 1 files changed, 57 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index c90c76a..5c8c521 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -166,48 +166,77 @@ static u32 acpi_osi_handler(acpi_string interface, u32 supported)
> return supported;
> }
>
> -static void __init acpi_request_region (struct acpi_generic_address *addr,
> +static int __init acpi_request_region(struct acpi_generic_address *addr,
> unsigned int length, char *desc)
> {
> + struct resource *pRes;
> +
> if (!addr->address || !length)
> - return;
> + return -EIO;
>
> /* Resources are never freed */
> - if (addr->space_id == ACPI_ADR_SPACE_SYSTEM_IO)
> - request_region(addr->address, length, desc);
> - else if (addr->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
> - request_mem_region(addr->address, length, desc);
> + if (addr->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
> + pRes = request_region(addr->address, length, desc);
> + if (pRes == NULL)
> + return -EIO;
> +
> + } else if (addr->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
> + pRes = request_mem_region(addr->address, length, desc);
> + if (pRes == NULL)
> + return -EIO;
> + }
> +
> + return 0;
> }
>
> static int __init acpi_reserve_resources(void)
> {
> - acpi_request_region(&acpi_gbl_FADT.xpm1a_event_block, acpi_gbl_FADT.pm1_event_length,
> - "ACPI PM1a_EVT_BLK");
> + if (!acpi_request_region(&acpi_gbl_FADT.xpm1a_event_block,
> + acpi_gbl_FADT.pm1_event_length,
> + "ACPI PM1a_EVT_BLK"))
> + return -EIO;
>
> - acpi_request_region(&acpi_gbl_FADT.xpm1b_event_block, acpi_gbl_FADT.pm1_event_length,
> - "ACPI PM1b_EVT_BLK");
> + if (!acpi_request_region(&acpi_gbl_FADT.xpm1b_event_block,
> + acpi_gbl_FADT.pm1_event_length,
> + "ACPI PM1b_EVT_BLK"))
> + return -EIO;
>
> - acpi_request_region(&acpi_gbl_FADT.xpm1a_control_block, acpi_gbl_FADT.pm1_control_length,
> - "ACPI PM1a_CNT_BLK");
> + if (!acpi_request_region(&acpi_gbl_FADT.xpm1a_control_block,
> + acpi_gbl_FADT.pm1_control_length,
> + "ACPI PM1a_CNT_BLK"))
> + return -EIO;
>
> - acpi_request_region(&acpi_gbl_FADT.xpm1b_control_block, acpi_gbl_FADT.pm1_control_length,
> - "ACPI PM1b_CNT_BLK");
> + if (!acpi_request_region(&acpi_gbl_FADT.xpm1b_control_block,
> + acpi_gbl_FADT.pm1_control_length,
> + "ACPI PM1b_CNT_BLK"))
> + return -EIO;
>
> - if (acpi_gbl_FADT.pm_timer_length == 4)
> - acpi_request_region(&acpi_gbl_FADT.xpm_timer_block, 4, "ACPI PM_TMR");
> + if (acpi_gbl_FADT.pm_timer_length == 4) {
> + if (!acpi_request_region(&acpi_gbl_FADT.xpm_timer_block,
> + 4, "ACPI PM_TMR"))
> + return -EIO;
> + }
>
> - acpi_request_region(&acpi_gbl_FADT.xpm2_control_block, acpi_gbl_FADT.pm2_control_length,
> - "ACPI PM2_CNT_BLK");
> + if (!acpi_request_region(&acpi_gbl_FADT.xpm2_control_block,
> + acpi_gbl_FADT.pm2_control_length,
> + "ACPI PM2_CNT_BLK"))
> + return -EIO;
>
> /* Length of GPE blocks must be a non-negative multiple of 2 */
>
> - if (!(acpi_gbl_FADT.gpe0_block_length & 0x1))
> - acpi_request_region(&acpi_gbl_FADT.xgpe0_block,
> - acpi_gbl_FADT.gpe0_block_length, "ACPI GPE0_BLK");
> + if (!(acpi_gbl_FADT.gpe0_block_length & 0x1)) {
> + if (!acpi_request_region(&acpi_gbl_FADT.xgpe0_block,
> + acpi_gbl_FADT.gpe0_block_length,
> + "ACPI GPE0_BLK"))
> + return -EIO;
> + }
>
> - if (!(acpi_gbl_FADT.gpe1_block_length & 0x1))
> - acpi_request_region(&acpi_gbl_FADT.xgpe1_block,
> - acpi_gbl_FADT.gpe1_block_length, "ACPI GPE1_BLK");
> + if (!(acpi_gbl_FADT.gpe1_block_length & 0x1)) {
> + if (!acpi_request_region(&acpi_gbl_FADT.xgpe1_block,
> + acpi_gbl_FADT.gpe1_block_length,
> + "ACPI GPE1_BLK"))
> + return -EIO;
> + }
>
> return 0;
> }
>



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