f2fs: factor out discard_cmd usage from general rb_tree use

This is a second part to remove the mixed use of rb_tree in discard_cmd from
extent_cache.

This should also fix arm32 memory alignment issue caused by shared rb_entry.

[struct discard_cmd]               [struct rb_entry]
[0] struct rb_node rb_node;        [0] struct rb_node rb_node;
  union {                              union {
    struct {                             struct {
[16]  block_t lstart;              [12]    unsigned int ofs;
      block_t len;                         unsigned int len;
                                         };
                                         unsigned long long key;
                                       } __packed;

Cc: <stable@vger.kernel.org>
Fixes: 004b6862 ("f2fs: use rb-tree to track pending discard commands")
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/extent_cache.c

@@ -192,7 +192,7 @@ static struct rb_entry *__lookup_rb_tree_slow(struct rb_root_cached *root,
 	return NULL;
 }
 
-struct rb_entry *f2fs_lookup_rb_tree(struct rb_root_cached *root,
+static struct rb_entry *f2fs_lookup_rb_tree(struct rb_root_cached *root,
 				struct rb_entry *cached_re, unsigned int ofs)
 {
 	struct rb_entry *re;
@@ -204,7 +204,7 @@ struct rb_entry *f2fs_lookup_rb_tree(struct rb_root_cached *root,
 	return re;
 }
 
-struct rb_node **f2fs_lookup_rb_tree_for_insert(struct f2fs_sb_info *sbi,
+static struct rb_node **f2fs_lookup_rb_tree_for_insert(struct f2fs_sb_info *sbi,
 				struct rb_root_cached *root,
 				struct rb_node **parent,
 				unsigned int ofs, bool *leftmost)
@@ -238,7 +238,7 @@ struct rb_node **f2fs_lookup_rb_tree_for_insert(struct f2fs_sb_info *sbi,
  * in order to simplify the insertion after.
  * tree must stay unchanged between lookup and insertion.
  */
-struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
+static struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
 				struct rb_entry *cached_re,
 				unsigned int ofs,
 				struct rb_entry **prev_entry,
@@ -311,36 +311,6 @@ struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
 	return re;
 }
 
-bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
-				struct rb_root_cached *root)
-{
-#ifdef CONFIG_F2FS_CHECK_FS
-	struct rb_node *cur = rb_first_cached(root), *next;
-	struct rb_entry *cur_re, *next_re;
-
-	if (!cur)
-		return true;
-
-	while (cur) {
-		next = rb_next(cur);
-		if (!next)
-			return true;
-
-		cur_re = rb_entry(cur, struct rb_entry, rb_node);
-		next_re = rb_entry(next, struct rb_entry, rb_node);
-
-		if (cur_re->ofs + cur_re->len > next_re->ofs) {
-			f2fs_info(sbi, "inconsistent rbtree, cur(%u, %u) next(%u, %u)",
-				  cur_re->ofs, cur_re->len,
-				  next_re->ofs, next_re->len);
-			return false;
-		}
-		cur = next;
-	}
-#endif
-	return true;
-}
-
 static struct kmem_cache *extent_tree_slab;
 static struct kmem_cache *extent_node_slab;
 

fs/f2fs/f2fs.h

@@ -353,15 +353,7 @@ struct discard_info {
 
 struct discard_cmd {
 	struct rb_node rb_node;		/* rb node located in rb-tree */
-	union {
-		struct {
-			block_t lstart;	/* logical start address */
-			block_t len;	/* length */
-			block_t start;	/* actual start address in dev */
-		};
-		struct discard_info di;	/* discard info */
-
-	};
+	struct discard_info di;		/* discard info */
 	struct list_head list;		/* command list */
 	struct completion wait;		/* compleation */
 	struct block_device *bdev;	/* bdev */
@@ -4132,19 +4124,6 @@ void f2fs_leave_shrinker(struct f2fs_sb_info *sbi);
  * extent_cache.c
  */
 bool sanity_check_extent_cache(struct inode *inode);
-struct rb_entry *f2fs_lookup_rb_tree(struct rb_root_cached *root,
-				struct rb_entry *cached_re, unsigned int ofs);
-struct rb_node **f2fs_lookup_rb_tree_for_insert(struct f2fs_sb_info *sbi,
-				struct rb_root_cached *root,
-				struct rb_node **parent,
-				unsigned int ofs, bool *leftmost);
-struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
-		struct rb_entry *cached_re, unsigned int ofs,
-		struct rb_entry **prev_entry, struct rb_entry **next_entry,
-		struct rb_node ***insert_p, struct rb_node **insert_parent,
-		bool force, bool *leftmost);
-bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
-				struct rb_root_cached *root);
 void f2fs_init_extent_tree(struct inode *inode);
 void f2fs_drop_extent_tree(struct inode *inode);
 void f2fs_destroy_extent_node(struct inode *inode);