+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;
+}
+