1 files changed, 42 insertions, 38 deletions

diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
index 88e4f3ff0cb8..673f8a128397 100644
--- a/drivers/ras/cec.c
+++ b/drivers/ras/cec.c
@@ -2,6 +2,7 @@
 #include <linux/mm.h>
 #include <linux/gfp.h>
 #include <linux/kernel.h>
+#include <linux/workqueue.h>
 
 #include <asm/mce.h>
 
@@ -123,16 +124,12 @@ static u64 dfs_pfn;
 /* Amount of errors after which we offline */
 static unsigned int count_threshold = COUNT_MASK;
 
-/*
- * The timer "decays" element count each timer_interval which is 24hrs by
- * default.
- */
-
-#define CEC_TIMER_DEFAULT_INTERVAL      24 * 60 * 60    /* 24 hrs */
-#define CEC_TIMER_MIN_INTERVAL           1 * 60 * 60    /* 1h */
-#define CEC_TIMER_MAX_INTERVAL     30 * 24 * 60 * 60    /* one month */
-static struct timer_list cec_timer;
-static u64 timer_interval = CEC_TIMER_DEFAULT_INTERVAL;
+/* Each element "decays" each decay_interval which is 24hrs by default. */
+#define CEC_DECAY_DEFAULT_INTERVAL      24 * 60 * 60    /* 24 hrs */
+#define CEC_DECAY_MIN_INTERVAL           1 * 60 * 60    /* 1h */
+#define CEC_DECAY_MAX_INTERVAL     30 * 24 * 60 * 60    /* one month */
+static struct delayed_work cec_work;
+static u64 decay_interval = CEC_DECAY_DEFAULT_INTERVAL;
 
 /*
  * Decrement decay value. We're using DECAY_BITS bits to denote decay of an
@@ -160,20 +157,21 @@ static void do_spring_cleaning(struct ce_array *ca)
 /*
  * @interval in seconds
  */
-static void cec_mod_timer(struct timer_list *t, unsigned long interval)
+static void cec_mod_work(unsigned long interval)
 {
         unsigned long iv;
 
-        iv = interval * HZ + jiffies;
-
-        mod_timer(t, round_jiffies(iv));
+        iv = interval * HZ;
+        mod_delayed_work(system_wq, &cec_work, round_jiffies(iv));
 }
 
-static void cec_timer_fn(struct timer_list *unused)
+static void cec_work_fn(struct work_struct *work)
 {
+        mutex_lock(&ce_mutex);
         do_spring_cleaning(&ce_arr);
+        mutex_unlock(&ce_mutex);
 
-        cec_mod_timer(&cec_timer, timer_interval);
+        cec_mod_work(decay_interval);
 }
 
 /*
@@ -183,32 +181,38 @@ static void cec_timer_fn(struct timer_list *unused)
  */
 static int __find_elem(struct ce_array *ca, u64 pfn, unsigned int *to)
 {
+        int min = 0, max = ca->n - 1;
         u64 this_pfn;
-        int min = 0, max = ca->n;
 
-        while (min < max) {
-                int tmp = (max + min) >> 1;
+        while (min <= max) {
+                int i = (min + max) >> 1;
 
-                this_pfn = PFN(ca->array[tmp]);
+                this_pfn = PFN(ca->array[i]);
 
                 if (this_pfn < pfn)
-                        min = tmp + 1;
+                        min = i + 1;
                 else if (this_pfn > pfn)
-                        max = tmp;
-                else {
-                        min = tmp;
-                        break;
+                        max = i - 1;
+                else if (this_pfn == pfn) {
+                        if (to)
+                                *to = i;
+
+                        return i;
                 }
         }
 
+        /*
+         * When the loop terminates without finding @pfn, min has the index of
+         * the element slot where the new @pfn should be inserted. The loop
+         * terminates when min > max, which means the min index points to the
+         * bigger element while the max index to the smaller element, in-between
+         * which the new @pfn belongs to.
+         *
+         * For more details, see exercise 1, Section 6.2.1 in TAOCP, vol. 3.
+         */
         if (to)
                 *to = min;
 
-        this_pfn = PFN(ca->array[min]);
-
-        if (this_pfn == pfn)
-                return min;
-
         return -ENOKEY;
 }
 
@@ -374,15 +378,15 @@ static int decay_interval_set(void *data, u64 val)
 {
         *(u64 *)data = val;
 
-        if (val < CEC_TIMER_MIN_INTERVAL)
+        if (val < CEC_DECAY_MIN_INTERVAL)
                 return -EINVAL;
 
-        if (val > CEC_TIMER_MAX_INTERVAL)
+        if (val > CEC_DECAY_MAX_INTERVAL)
                 return -EINVAL;
 
-        timer_interval = val;
+        decay_interval = val;
 
-        cec_mod_timer(&cec_timer, timer_interval);
+        cec_mod_work(decay_interval);
         return 0;
 }
 DEFINE_DEBUGFS_ATTRIBUTE(decay_interval_ops, u64_get, decay_interval_set, "%lld\n");
@@ -426,7 +430,7 @@ static int array_dump(struct seq_file *m, void *v)
 
         seq_printf(m, "Flags: 0x%x\n", ca->flags);
 
-        seq_printf(m, "Timer interval: %lld seconds\n", timer_interval);
+        seq_printf(m, "Decay interval: %lld seconds\n", decay_interval);
         seq_printf(m, "Decays: %lld\n", ca->decays_done);
 
         seq_printf(m, "Action threshold: %d\n", count_threshold);
@@ -472,7 +476,7 @@ static int __init create_debugfs_nodes(void)
         }
 
         decay = debugfs_create_file("decay_interval", S_IRUSR | S_IWUSR, d,
-                                    &timer_interval, &decay_interval_ops);
+                                    &decay_interval, &decay_interval_ops);
         if (!decay) {
                 pr_warn("Error creating decay_interval debugfs node!\n");
                 goto err;
@@ -508,8 +512,8 @@ void __init cec_init(void)
         if (create_debugfs_nodes())
                 return;
 
-        timer_setup(&cec_timer, cec_timer_fn, 0);
-        cec_mod_timer(&cec_timer, CEC_TIMER_DEFAULT_INTERVAL);
+        INIT_DELAYED_WORK(&cec_work, cec_work_fn);
+        schedule_delayed_work(&cec_work, CEC_DECAY_DEFAULT_INTERVAL);
 
         pr_info("Correctable Errors collector initialized.\n");
 }