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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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