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    Subject[PATCH v3 09/11] drivers/char/ipmi: convert stats to use 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 wrap around to INT_MIN when it overflows and
    should not be used to guard resource lifetimes, device usage and open
    counts that control state changes, and pm states.

    atomic_t variables used for stats are atomic counters. Overflow will
    wrap around and reset the stats and no change with the conversion.

    Convert them to use counter_atomic32.

    Reviewed-by: Corey Minyard <cminyard@mvista.com>
    Reviewed-by: Kees Cook <keescook@chromium.org>
    Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
    ---
    drivers/char/ipmi/ipmi_msghandler.c | 9 +++++----
    drivers/char/ipmi/ipmi_si_intf.c | 9 +++++----
    2 files changed, 10 insertions(+), 8 deletions(-)

    diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
    index 737c0b6b24ea..36c0b1be22fb 100644
    --- a/drivers/char/ipmi/ipmi_msghandler.c
    +++ b/drivers/char/ipmi/ipmi_msghandler.c
    @@ -34,6 +34,7 @@
    #include <linux/uuid.h>
    #include <linux/nospec.h>
    #include <linux/vmalloc.h>
    +#include <linux/counters.h>

    #define IPMI_DRIVER_VERSION "39.2"

    @@ -584,7 +585,7 @@ struct ipmi_smi {
    struct ipmi_my_addrinfo addrinfo[IPMI_MAX_CHANNELS];
    bool channels_ready;

    - atomic_t stats[IPMI_NUM_STATS];
    + struct counter_atomic32 stats[IPMI_NUM_STATS];

    /*
    * run_to_completion duplicate of smb_info, smi_info
    @@ -630,9 +631,9 @@ static LIST_HEAD(smi_watchers);
    static DEFINE_MUTEX(smi_watchers_mutex);

    #define ipmi_inc_stat(intf, stat) \
    - atomic_inc(&(intf)->stats[IPMI_STAT_ ## stat])
    + counter_atomic32_inc(&(intf)->stats[IPMI_STAT_ ## stat])
    #define ipmi_get_stat(intf, stat) \
    - ((unsigned int) atomic_read(&(intf)->stats[IPMI_STAT_ ## stat]))
    + ((unsigned int) counter_atomic32_read(&(intf)->stats[IPMI_STAT_ ## stat]))

    static const char * const addr_src_to_str[] = {
    "invalid", "hotmod", "hardcoded", "SPMI", "ACPI", "SMBIOS", "PCI",
    @@ -3448,7 +3449,7 @@ int ipmi_add_smi(struct module *owner,
    INIT_LIST_HEAD(&intf->cmd_rcvrs);
    init_waitqueue_head(&intf->waitq);
    for (i = 0; i < IPMI_NUM_STATS; i++)
    - atomic_set(&intf->stats[i], 0);
    + counter_atomic32_set(&intf->stats[i], 0);

    mutex_lock(&ipmi_interfaces_mutex);
    /* Look for a hole in the numbers. */
    diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
    index 77b8d551ae7f..0909a3461f05 100644
    --- a/drivers/char/ipmi/ipmi_si_intf.c
    +++ b/drivers/char/ipmi/ipmi_si_intf.c
    @@ -43,6 +43,7 @@
    #include "ipmi_si_sm.h"
    #include <linux/string.h>
    #include <linux/ctype.h>
    +#include <linux/counters.h>

    /* Measure times between events in the driver. */
    #undef DEBUG_TIMING
    @@ -237,7 +238,7 @@ struct smi_info {
    bool dev_group_added;

    /* Counters and things for the proc filesystem. */
    - atomic_t stats[SI_NUM_STATS];
    + struct counter_atomic32 stats[SI_NUM_STATS];

    struct task_struct *thread;

    @@ -245,9 +246,9 @@ struct smi_info {
    };

    #define smi_inc_stat(smi, stat) \
    - atomic_inc(&(smi)->stats[SI_STAT_ ## stat])
    + counter_atomic32_inc(&(smi)->stats[SI_STAT_ ## stat])
    #define smi_get_stat(smi, stat) \
    - ((unsigned int) atomic_read(&(smi)->stats[SI_STAT_ ## stat]))
    + ((unsigned int) counter_atomic32_read(&(smi)->stats[SI_STAT_ ## stat]))

    #define IPMI_MAX_INTFS 4
    static int force_kipmid[IPMI_MAX_INTFS];
    @@ -2013,7 +2014,7 @@ static int try_smi_init(struct smi_info *new_smi)
    atomic_set(&new_smi->req_events, 0);
    new_smi->run_to_completion = false;
    for (i = 0; i < SI_NUM_STATS; i++)
    - atomic_set(&new_smi->stats[i], 0);
    + counter_atomic32_set(&new_smi->stats[i], 0);

    new_smi->interrupt_disabled = true;
    atomic_set(&new_smi->need_watch, 0);
    --
    2.25.1
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