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    Subject[PATCH v2 05/11] drivers/acpi: convert seqno counter_atomic32
    Date
    counter_atomic* is introduced to be used when a variable is used as
    a simple counter and doesn't guard object lifetimes. This clearly
    differentiates atomic_t usages that guard object lifetimes.

    counter_atomic* variables will wrap around to 0 when it overflows and
    should not be used to guard resource lifetimes, device usage and
    open counts that control state changes, and pm states.

    seqno is a sequence number counter for logging. This counter gets
    incremented. Unsure if there is a chance of this overflowing. It
    doesn't look like overflowing causes any problems since it is used
    to tag the log messages and nothing more.

    Convert it to use counter_atomic32.

    This conversion doesn't change the overflow wrap around behavior.

    Acked-by: Rafael J. Wysocki <rafael@kernel.org>
    Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
    ---
    drivers/acpi/acpi_extlog.c | 5 +++--
    1 file changed, 3 insertions(+), 2 deletions(-)

    diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
    index f138e12b7b82..d1e733f15cf5 100644
    --- a/drivers/acpi/acpi_extlog.c
    +++ b/drivers/acpi/acpi_extlog.c
    @@ -12,6 +12,7 @@
    #include <linux/ratelimit.h>
    #include <linux/edac.h>
    #include <linux/ras.h>
    +#include <linux/counters.h>
    #include <asm/cpu.h>
    #include <asm/mce.h>

    @@ -93,7 +94,7 @@ static struct acpi_hest_generic_status *extlog_elog_entry_check(int cpu, int ban
    static void __print_extlog_rcd(const char *pfx,
    struct acpi_hest_generic_status *estatus, int cpu)
    {
    - static atomic_t seqno;
    + static struct counter_atomic32 seqno;
    unsigned int curr_seqno;
    char pfx_seq[64];

    @@ -103,7 +104,7 @@ static void __print_extlog_rcd(const char *pfx,
    else
    pfx = KERN_ERR;
    }
    - curr_seqno = atomic_inc_return(&seqno);
    + curr_seqno = counter_atomic32_inc_return(&seqno);
    snprintf(pfx_seq, sizeof(pfx_seq), "%s{%u}", pfx, curr_seqno);
    printk("%s""Hardware error detected on CPU%d\n", pfx_seq, cpu);
    cper_estatus_print(pfx_seq, estatus);
    --
    2.25.1
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