ipmi: convert locked counters to atomics in the system interface

Atomics are faster and neater than locked counters.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 66 insertions, 74 deletions

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 657034febdaf..286c042a0c66 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -120,6 +120,27 @@ static struct device_driver ipmi_driver =
         .bus = &platform_bus_type
 };
 
+
+/*
+ * Indexes into stats[] in smi_info below.
+ */
+
+#define SI_STAT_short_timeouts          0
+#define SI_STAT_long_timeouts           1
+#define SI_STAT_timeout_restarts        2
+#define SI_STAT_idles                   3
+#define SI_STAT_interrupts              4
+#define SI_STAT_attentions              5
+#define SI_STAT_flag_fetches            6
+#define SI_STAT_hosed_count             7
+#define SI_STAT_complete_transactions   8
+#define SI_STAT_events                  9
+#define SI_STAT_watchdog_pretimeouts    10
+#define SI_STAT_incoming_messages       11
+
+/* If you add a stat, you must update this value. */
+#define SI_NUM_STATS                    12
+
 struct smi_info
 {
         int                    intf_num;
@@ -216,25 +237,18 @@ struct smi_info
         unsigned char slave_addr;
 
         /* Counters and things for the proc filesystem. */
-        spinlock_t count_lock;
-        unsigned long short_timeouts;
-        unsigned long long_timeouts;
-        unsigned long timeout_restarts;
-        unsigned long idles;
-        unsigned long interrupts;
-        unsigned long attentions;
-        unsigned long flag_fetches;
-        unsigned long hosed_count;
-        unsigned long complete_transactions;
-        unsigned long events;
-        unsigned long watchdog_pretimeouts;
-        unsigned long incoming_messages;
+        atomic_t stats[SI_NUM_STATS];
 
         struct task_struct *thread;
 
         struct list_head link;
 };
 
+#define smi_inc_stat(smi, stat) \
+        atomic_inc(&(smi)->stats[SI_STAT_ ## stat])
+#define smi_get_stat(smi, stat) \
+        ((unsigned int) atomic_read(&(smi)->stats[SI_STAT_ ## stat]))
+
 #define SI_MAX_PARMS 4
 
 static int force_kipmid[SI_MAX_PARMS];
@@ -398,9 +412,7 @@ static void handle_flags(struct smi_info *smi_info)
  retry:
         if (smi_info->msg_flags & WDT_PRE_TIMEOUT_INT) {
                 /* Watchdog pre-timeout */
-                spin_lock(&smi_info->count_lock);
-                smi_info->watchdog_pretimeouts++;
-                spin_unlock(&smi_info->count_lock);
+                smi_inc_stat(smi_info, watchdog_pretimeouts);
 
                 start_clear_flags(smi_info);
                 smi_info->msg_flags &= ~WDT_PRE_TIMEOUT_INT;
@@ -545,9 +557,7 @@ static void handle_transaction_done(struct smi_info *smi_info)
                         smi_info->msg_flags &= ~EVENT_MSG_BUFFER_FULL;
                         handle_flags(smi_info);
                 } else {
-                        spin_lock(&smi_info->count_lock);
-                        smi_info->events++;
-                        spin_unlock(&smi_info->count_lock);
+                        smi_inc_stat(smi_info, events);
 
                         /* Do this before we deliver the message
                            because delivering the message releases the
@@ -581,9 +591,7 @@ static void handle_transaction_done(struct smi_info *smi_info)
                         smi_info->msg_flags &= ~RECEIVE_MSG_AVAIL;
                         handle_flags(smi_info);
                 } else {
-                        spin_lock(&smi_info->count_lock);
-                        smi_info->incoming_messages++;
-                        spin_unlock(&smi_info->count_lock);
+                        smi_inc_stat(smi_info, incoming_messages);
 
                         /* Do this before we deliver the message
                            because delivering the message releases the
@@ -700,18 +708,14 @@ static enum si_sm_result smi_event_handler(struct smi_info *smi_info,
 
         if (si_sm_result == SI_SM_TRANSACTION_COMPLETE)
         {
-                spin_lock(&smi_info->count_lock);
-                smi_info->complete_transactions++;
-                spin_unlock(&smi_info->count_lock);
+                smi_inc_stat(smi_info, complete_transactions);
 
                 handle_transaction_done(smi_info);
                 si_sm_result = smi_info->handlers->event(smi_info->si_sm, 0);
         }
         else if (si_sm_result == SI_SM_HOSED)
         {
-                spin_lock(&smi_info->count_lock);
-                smi_info->hosed_count++;
-                spin_unlock(&smi_info->count_lock);
+                smi_inc_stat(smi_info, hosed_count);
 
                 /* Do the before return_hosed_msg, because that
                    releases the lock. */
@@ -733,9 +737,7 @@ static enum si_sm_result smi_event_handler(struct smi_info *smi_info,
         {
                 unsigned char msg[2];
 
-                spin_lock(&smi_info->count_lock);
-                smi_info->attentions++;
-                spin_unlock(&smi_info->count_lock);
+                smi_inc_stat(smi_info, attentions);
 
                 /* Got a attn, send down a get message flags to see
                    what's causing it.  It would be better to handle
@@ -753,9 +755,7 @@ static enum si_sm_result smi_event_handler(struct smi_info *smi_info,
 
         /* If we are currently idle, try to start the next message. */
         if (si_sm_result == SI_SM_IDLE) {
-                spin_lock(&smi_info->count_lock);
-                smi_info->idles++;
-                spin_unlock(&smi_info->count_lock);
+                smi_inc_stat(smi_info, idles);
 
                 si_sm_result = start_next_msg(smi_info);
                 if (si_sm_result != SI_SM_IDLE)
@@ -945,23 +945,17 @@ static void smi_timeout(unsigned long data)
         if ((smi_info->irq) && (!smi_info->interrupt_disabled)) {
                 /* Running with interrupts, only do long timeouts. */
                 smi_info->si_timer.expires = jiffies + SI_TIMEOUT_JIFFIES;
-                spin_lock_irqsave(&smi_info->count_lock, flags);
-                smi_info->long_timeouts++;
-                spin_unlock_irqrestore(&smi_info->count_lock, flags);
+                smi_inc_stat(smi_info, long_timeouts);
                 goto do_add_timer;
         }
 
         /* If the state machine asks for a short delay, then shorten
            the timer timeout. */
         if (smi_result == SI_SM_CALL_WITH_DELAY) {
-                spin_lock_irqsave(&smi_info->count_lock, flags);
-                smi_info->short_timeouts++;
-                spin_unlock_irqrestore(&smi_info->count_lock, flags);
+                smi_inc_stat(smi_info, short_timeouts);
                 smi_info->si_timer.expires = jiffies + 1;
         } else {
-                spin_lock_irqsave(&smi_info->count_lock, flags);
-                smi_info->long_timeouts++;
-                spin_unlock_irqrestore(&smi_info->count_lock, flags);
+                smi_inc_stat(smi_info, long_timeouts);
                 smi_info->si_timer.expires = jiffies + SI_TIMEOUT_JIFFIES;
         }
 
@@ -979,9 +973,7 @@ static irqreturn_t si_irq_handler(int irq, void *data)
 
         spin_lock_irqsave(&(smi_info->si_lock), flags);
 
-        spin_lock(&smi_info->count_lock);
-        smi_info->interrupts++;
-        spin_unlock(&smi_info->count_lock);
+        smi_inc_stat(smi_info, interrupts);
 
 #ifdef DEBUG_TIMING
         do_gettimeofday(&t);
@@ -1765,9 +1757,7 @@ static u32 ipmi_acpi_gpe(void *context)
 
         spin_lock_irqsave(&(smi_info->si_lock), flags);
 
-        spin_lock(&smi_info->count_lock);
-        smi_info->interrupts++;
-        spin_unlock(&smi_info->count_lock);
+        smi_inc_stat(smi_info, interrupts);
 
 #ifdef DEBUG_TIMING
         do_gettimeofday(&t);
@@ -2405,30 +2395,30 @@ static int stat_file_read_proc(char *page, char **start, off_t off,
 
         out += sprintf(out, "interrupts_enabled:    %d\n",
                        smi->irq && !smi->interrupt_disabled);
-        out += sprintf(out, "short_timeouts:        %ld\n",
-                       smi->short_timeouts);
-        out += sprintf(out, "long_timeouts:         %ld\n",
-                       smi->long_timeouts);
-        out += sprintf(out, "timeout_restarts:      %ld\n",
-                       smi->timeout_restarts);
-        out += sprintf(out, "idles:                 %ld\n",
-                       smi->idles);
-        out += sprintf(out, "interrupts:            %ld\n",
-                       smi->interrupts);
-        out += sprintf(out, "attentions:            %ld\n",
-                       smi->attentions);
-        out += sprintf(out, "flag_fetches:          %ld\n",
-                       smi->flag_fetches);
-        out += sprintf(out, "hosed_count:           %ld\n",
-                       smi->hosed_count);
-        out += sprintf(out, "complete_transactions: %ld\n",
-                       smi->complete_transactions);
-        out += sprintf(out, "events:                %ld\n",
-                       smi->events);
-        out += sprintf(out, "watchdog_pretimeouts:  %ld\n",
-                       smi->watchdog_pretimeouts);
-        out += sprintf(out, "incoming_messages:     %ld\n",
-                       smi->incoming_messages);
+        out += sprintf(out, "short_timeouts:        %u\n",
+                       smi_get_stat(smi, short_timeouts));
+        out += sprintf(out, "long_timeouts:         %u\n",
+                       smi_get_stat(smi, long_timeouts));
+        out += sprintf(out, "timeout_restarts:      %u\n",
+                       smi_get_stat(smi, timeout_restarts));
+        out += sprintf(out, "idles:                 %u\n",
+                       smi_get_stat(smi, idles));
+        out += sprintf(out, "interrupts:            %u\n",
+                       smi_get_stat(smi, interrupts));
+        out += sprintf(out, "attentions:            %u\n",
+                       smi_get_stat(smi, attentions));
+        out += sprintf(out, "flag_fetches:          %u\n",
+                       smi_get_stat(smi, flag_fetches));
+        out += sprintf(out, "hosed_count:           %u\n",
+                       smi_get_stat(smi, hosed_count));
+        out += sprintf(out, "complete_transactions: %u\n",
+                       smi_get_stat(smi, complete_transactions));
+        out += sprintf(out, "events:                %u\n",
+                       smi_get_stat(smi, events));
+        out += sprintf(out, "watchdog_pretimeouts:  %u\n",
+                       smi_get_stat(smi, watchdog_pretimeouts));
+        out += sprintf(out, "incoming_messages:     %u\n",
+                       smi_get_stat(smi, incoming_messages));
 
         return out - page;
 }
@@ -2676,6 +2666,7 @@ static int is_new_interface(struct smi_info *info)
 static int try_smi_init(struct smi_info *new_smi)
 {
         int rv;
+        int i;
 
         if (new_smi->addr_source) {
                 printk(KERN_INFO "ipmi_si: Trying %s-specified %s state"
@@ -2738,7 +2729,6 @@ static int try_smi_init(struct smi_info *new_smi)
 
         spin_lock_init(&(new_smi->si_lock));
         spin_lock_init(&(new_smi->msg_lock));
-        spin_lock_init(&(new_smi->count_lock));
 
         /* Do low-level detection first. */
         if (new_smi->handlers->detect(new_smi->si_sm)) {
@@ -2767,6 +2757,8 @@ static int try_smi_init(struct smi_info *new_smi)
         new_smi->curr_msg = NULL;
         atomic_set(&new_smi->req_events, 0);
         new_smi->run_to_completion = 0;
+        for (i = 0; i < SI_NUM_STATS; i++)
+                atomic_set(&new_smi->stats[i], 0);
 
         new_smi->interrupt_disabled = 0;
         atomic_set(&new_smi->stop_operation, 0);