[PATCH v3 09/11] drivers/char/ipmi: convert stats to use counter_atomic32

Shuah Khan
2020-10-09T15:56:42Z

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