Merge tag 'regmap-debugfs-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull regmap debugfs optimisation fixes from Mark Brown:
 "The debugfs optimisations merged in v3.8 weren't my finest hour, there
  were a number of cases that the more complex algorithm made worse
  especially around the error handling.  This patch series should
  address those issues."

* tag 'regmap-debugfs-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: debugfs: Make sure we store the last entry in the offset cache
  regmap: debugfs: Ensure a correct return value for empty caches
  regmap: debugfs: Discard the cache if we fail to allocate an entry
  regmap: debugfs: Fix check for block start in cached seeks
  regmap: debugfs: Fix attempts to read nonexistant register blocks

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 07aad786f817e88300af9c4d6d685391f41b3471..46a213a596e29ec5ae142477e40c563744f49ede 100644 (file)
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -56,6 +56,19 @@ static const struct file_operations regmap_name_fops = {
        .llseek = default_llseek,
 };
 
+static void regmap_debugfs_free_dump_cache(struct regmap *map)
+{
+       struct regmap_debugfs_off_cache *c;
+
+       while (!list_empty(&map->debugfs_off_cache)) {
+               c = list_first_entry(&map->debugfs_off_cache,
+                                    struct regmap_debugfs_off_cache,
+                                    list);
+               list_del(&c->list);
+               kfree(c);
+       }
+}
+
 /*
  * Work out where the start offset maps into register numbers, bearing
  * in mind that we suppress hidden registers.
@@ -91,8 +104,10 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
                        /* No cache entry?  Start a new one */
                        if (!c) {
                                c = kzalloc(sizeof(*c), GFP_KERNEL);
-                               if (!c)
-                                       break;
+                               if (!c) {
+                                       regmap_debugfs_free_dump_cache(map);
+                                       return base;
+                               }
                                c->min = p;
                                c->base_reg = i;
                        }
@@ -101,14 +116,34 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
                }
        }
 
+       /* Close the last entry off if we didn't scan beyond it */
+       if (c) {
+               c->max = p - 1;
+               list_add_tail(&c->list,
+                             &map->debugfs_off_cache);
+       } else {
+               return base;
+       }
+
+       /*
+        * This should never happen; we return above if we fail to
+        * allocate and we should never be in this code if there are
+        * no registers at all.
+        */
+       if (list_empty(&map->debugfs_off_cache)) {
+               WARN_ON(list_empty(&map->debugfs_off_cache));
+               return base;
+       }
+
        /* Find the relevant block */
        list_for_each_entry(c, &map->debugfs_off_cache, list) {
-               if (*pos >= c->min && *pos <= c->max) {
+               if (from >= c->min && from <= c->max) {
                        *pos = c->min;
                        return c->base_reg;
                }
 
-               ret = c->max;
+               *pos = c->min;
+               ret = c->base_reg;
        }
 
        return ret;
@@ -387,16 +422,8 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
 
 void regmap_debugfs_exit(struct regmap *map)
 {
-       struct regmap_debugfs_off_cache *c;
-
        debugfs_remove_recursive(map->debugfs);
-       while (!list_empty(&map->debugfs_off_cache)) {
-               c = list_first_entry(&map->debugfs_off_cache,
-                                    struct regmap_debugfs_off_cache,
-                                    list);
-               list_del(&c->list);
-               kfree(c);
-       }
+       regmap_debugfs_free_dump_cache(map);
        kfree(map->debugfs_name);
 }