Merge branch 'linus' into release
[pandora-kernel.git] / drivers / acpi / apei / erst.c
index c02005a..d6cb0ff 100644 (file)
@@ -430,6 +430,22 @@ ssize_t erst_get_record_count(void)
 }
 EXPORT_SYMBOL_GPL(erst_get_record_count);
 
+#define ERST_RECORD_ID_CACHE_SIZE_MIN  16
+#define ERST_RECORD_ID_CACHE_SIZE_MAX  1024
+
+struct erst_record_id_cache {
+       struct mutex lock;
+       u64 *entries;
+       int len;
+       int size;
+       int refcount;
+};
+
+static struct erst_record_id_cache erst_record_id_cache = {
+       .lock = __MUTEX_INITIALIZER(erst_record_id_cache.lock),
+       .refcount = 0,
+};
+
 static int __erst_get_next_record_id(u64 *record_id)
 {
        struct apei_exec_context ctx;
@@ -444,26 +460,179 @@ static int __erst_get_next_record_id(u64 *record_id)
        return 0;
 }
 
+int erst_get_record_id_begin(int *pos)
+{
+       int rc;
+
+       if (erst_disable)
+               return -ENODEV;
+
+       rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
+       if (rc)
+               return rc;
+       erst_record_id_cache.refcount++;
+       mutex_unlock(&erst_record_id_cache.lock);
+
+       *pos = 0;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(erst_get_record_id_begin);
+
+/* erst_record_id_cache.lock must be held by caller */
+static int __erst_record_id_cache_add_one(void)
+{
+       u64 id, prev_id, first_id;
+       int i, rc;
+       u64 *entries;
+       unsigned long flags;
+
+       id = prev_id = first_id = APEI_ERST_INVALID_RECORD_ID;
+retry:
+       raw_spin_lock_irqsave(&erst_lock, flags);
+       rc = __erst_get_next_record_id(&id);
+       raw_spin_unlock_irqrestore(&erst_lock, flags);
+       if (rc == -ENOENT)
+               return 0;
+       if (rc)
+               return rc;
+       if (id == APEI_ERST_INVALID_RECORD_ID)
+               return 0;
+       /* can not skip current ID, or loop back to first ID */
+       if (id == prev_id || id == first_id)
+               return 0;
+       if (first_id == APEI_ERST_INVALID_RECORD_ID)
+               first_id = id;
+       prev_id = id;
+
+       entries = erst_record_id_cache.entries;
+       for (i = 0; i < erst_record_id_cache.len; i++) {
+               if (entries[i] == id)
+                       break;
+       }
+       /* record id already in cache, try next */
+       if (i < erst_record_id_cache.len)
+               goto retry;
+       if (erst_record_id_cache.len >= erst_record_id_cache.size) {
+               int new_size, alloc_size;
+               u64 *new_entries;
+
+               new_size = erst_record_id_cache.size * 2;
+               new_size = clamp_val(new_size, ERST_RECORD_ID_CACHE_SIZE_MIN,
+                                    ERST_RECORD_ID_CACHE_SIZE_MAX);
+               if (new_size <= erst_record_id_cache.size) {
+                       if (printk_ratelimit())
+                               pr_warning(FW_WARN ERST_PFX
+                                          "too many record ID!\n");
+                       return 0;
+               }
+               alloc_size = new_size * sizeof(entries[0]);
+               if (alloc_size < PAGE_SIZE)
+                       new_entries = kmalloc(alloc_size, GFP_KERNEL);
+               else
+                       new_entries = vmalloc(alloc_size);
+               if (!new_entries)
+                       return -ENOMEM;
+               memcpy(new_entries, entries,
+                      erst_record_id_cache.len * sizeof(entries[0]));
+               if (erst_record_id_cache.size < PAGE_SIZE)
+                       kfree(entries);
+               else
+                       vfree(entries);
+               erst_record_id_cache.entries = entries = new_entries;
+               erst_record_id_cache.size = new_size;
+       }
+       entries[i] = id;
+       erst_record_id_cache.len++;
+
+       return 1;
+}
+
 /*
  * Get the record ID of an existing error record on the persistent
  * storage. If there is no error record on the persistent storage, the
  * returned record_id is APEI_ERST_INVALID_RECORD_ID.
  */
-int erst_get_next_record_id(u64 *record_id)
+int erst_get_record_id_next(int *pos, u64 *record_id)
 {
-       int rc;
-       unsigned long flags;
+       int rc = 0;
+       u64 *entries;
 
        if (erst_disable)
                return -ENODEV;
 
-       raw_spin_lock_irqsave(&erst_lock, flags);
-       rc = __erst_get_next_record_id(record_id);
-       raw_spin_unlock_irqrestore(&erst_lock, flags);
+       /* must be enclosed by erst_get_record_id_begin/end */
+       BUG_ON(!erst_record_id_cache.refcount);
+       BUG_ON(*pos < 0 || *pos > erst_record_id_cache.len);
+
+       mutex_lock(&erst_record_id_cache.lock);
+       entries = erst_record_id_cache.entries;
+       for (; *pos < erst_record_id_cache.len; (*pos)++)
+               if (entries[*pos] != APEI_ERST_INVALID_RECORD_ID)
+                       break;
+       /* found next record id in cache */
+       if (*pos < erst_record_id_cache.len) {
+               *record_id = entries[*pos];
+               (*pos)++;
+               goto out_unlock;
+       }
+
+       /* Try to add one more record ID to cache */
+       rc = __erst_record_id_cache_add_one();
+       if (rc < 0)
+               goto out_unlock;
+       /* successfully add one new ID */
+       if (rc == 1) {
+               *record_id = erst_record_id_cache.entries[*pos];
+               (*pos)++;
+               rc = 0;
+       } else {
+               *pos = -1;
+               *record_id = APEI_ERST_INVALID_RECORD_ID;
+       }
+out_unlock:
+       mutex_unlock(&erst_record_id_cache.lock);
 
        return rc;
 }
-EXPORT_SYMBOL_GPL(erst_get_next_record_id);
+EXPORT_SYMBOL_GPL(erst_get_record_id_next);
+
+/* erst_record_id_cache.lock must be held by caller */
+static void __erst_record_id_cache_compact(void)
+{
+       int i, wpos = 0;
+       u64 *entries;
+
+       if (erst_record_id_cache.refcount)
+               return;
+
+       entries = erst_record_id_cache.entries;
+       for (i = 0; i < erst_record_id_cache.len; i++) {
+               if (entries[i] == APEI_ERST_INVALID_RECORD_ID)
+                       continue;
+               if (wpos != i)
+                       memcpy(&entries[wpos], &entries[i], sizeof(entries[i]));
+               wpos++;
+       }
+       erst_record_id_cache.len = wpos;
+}
+
+void erst_get_record_id_end(void)
+{
+       /*
+        * erst_disable != 0 should be detected by invoker via the
+        * return value of erst_get_record_id_begin/next, so this
+        * function should not be called for erst_disable != 0.
+        */
+       BUG_ON(erst_disable);
+
+       mutex_lock(&erst_record_id_cache.lock);
+       erst_record_id_cache.refcount--;
+       BUG_ON(erst_record_id_cache.refcount < 0);
+       __erst_record_id_cache_compact();
+       mutex_unlock(&erst_record_id_cache.lock);
+}
+EXPORT_SYMBOL_GPL(erst_get_record_id_end);
 
 static int __erst_write_to_storage(u64 offset)
 {
@@ -704,56 +873,34 @@ ssize_t erst_read(u64 record_id, struct cper_record_header *record,
 }
 EXPORT_SYMBOL_GPL(erst_read);
 
-/*
- * If return value > buflen, the buffer size is not big enough,
- * else if return value = 0, there is no more record to read,
- * else if return value < 0, something goes wrong,
- * else everything is OK, and return value is record length
- */
-ssize_t erst_read_next(struct cper_record_header *record, size_t buflen)
-{
-       int rc;
-       ssize_t len;
-       unsigned long flags;
-       u64 record_id;
-
-       if (erst_disable)
-               return -ENODEV;
-
-       raw_spin_lock_irqsave(&erst_lock, flags);
-       rc = __erst_get_next_record_id(&record_id);
-       if (rc) {
-               raw_spin_unlock_irqrestore(&erst_lock, flags);
-               return rc;
-       }
-       /* no more record */
-       if (record_id == APEI_ERST_INVALID_RECORD_ID) {
-               raw_spin_unlock_irqrestore(&erst_lock, flags);
-               return 0;
-       }
-
-       len = __erst_read(record_id, record, buflen);
-       raw_spin_unlock_irqrestore(&erst_lock, flags);
-
-       return len;
-}
-EXPORT_SYMBOL_GPL(erst_read_next);
-
 int erst_clear(u64 record_id)
 {
-       int rc;
+       int rc, i;
        unsigned long flags;
+       u64 *entries;
 
        if (erst_disable)
                return -ENODEV;
 
+       rc = mutex_lock_interruptible(&erst_record_id_cache.lock);
+       if (rc)
+               return rc;
        raw_spin_lock_irqsave(&erst_lock, flags);
        if (erst_erange.attr & ERST_RANGE_NVRAM)
                rc = __erst_clear_from_nvram(record_id);
        else
                rc = __erst_clear_from_storage(record_id);
        raw_spin_unlock_irqrestore(&erst_lock, flags);
-
+       if (rc)
+               goto out;
+       entries = erst_record_id_cache.entries;
+       for (i = 0; i < erst_record_id_cache.len; i++) {
+               if (entries[i] == record_id)
+                       entries[i] = APEI_ERST_INVALID_RECORD_ID;
+       }
+       __erst_record_id_cache_compact();
+out:
+       mutex_unlock(&erst_record_id_cache.lock);
        return rc;
 }
 EXPORT_SYMBOL_GPL(erst_clear);