From: Matthew Wilcox <willy@infradead.org>
Date: Thu, 18 Oct 2018 19:36:42 +0000 (-0400)
Subject: erofs: Convert workstn_tree to XArray
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=839c0669fd2aef830fb8701da8663bf218cddd80;p=users%2Fwilly%2Fxarray.git

erofs: Convert workstn_tree to XArray

Rename it to compression_work as a better reflection of what it's for.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
---

diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
index 963cc1b8b8961..ca16abca8598c 100644
--- a/drivers/staging/erofs/internal.h
+++ b/drivers/staging/erofs/internal.h
@@ -93,8 +93,7 @@ struct erofs_sb_info {
 	/* cluster size in bit shift */
 	unsigned char clusterbits;
 
-	/* the dedicated workstation for compression */
-	struct radix_tree_root workstn_tree;
+	struct xarray compression_work;
 
 	/* threshold for decompression synchronously */
 	unsigned int max_sync_decompress_pages;
@@ -183,8 +182,6 @@ static inline void *erofs_kmalloc(struct erofs_sb_info *sbi,
 #define test_opt(sbi, option)	((sbi)->mount_opt & EROFS_MOUNT_##option)
 
 #ifdef CONFIG_EROFS_FS_ZIP
-#define erofs_workstn_lock(sbi)         xa_lock(&(sbi)->workstn_tree)
-#define erofs_workstn_unlock(sbi)       xa_unlock(&(sbi)->workstn_tree)
 
 /* basic unit of the workstation of a super_block */
 struct erofs_workgroup {
diff --git a/drivers/staging/erofs/super.c b/drivers/staging/erofs/super.c
index 54494412eba41..f9964d40aed32 100644
--- a/drivers/staging/erofs/super.c
+++ b/drivers/staging/erofs/super.c
@@ -421,7 +421,7 @@ static int erofs_read_super(struct super_block *sb,
 		sb->s_flags &= ~SB_POSIXACL;
 
 #ifdef CONFIG_EROFS_FS_ZIP
-	INIT_RADIX_TREE(&sbi->workstn_tree, GFP_ATOMIC);
+	xa_init(&sbi->compression_work);
 #endif
 
 #ifdef EROFS_FS_HAS_MANAGED_CACHE
diff --git a/drivers/staging/erofs/utils.c b/drivers/staging/erofs/utils.c
index 4bbd3bf34acd9..9e9163a2bd777 100644
--- a/drivers/staging/erofs/utils.c
+++ b/drivers/staging/erofs/utils.c
@@ -72,7 +72,7 @@ struct erofs_workgroup *erofs_find_workgroup(struct super_block *sb,
 
 repeat:
 	rcu_read_lock();
-	grp = radix_tree_lookup(&sbi->workstn_tree, index);
+	grp = xa_load(&sbi->compression_work, index);
 	if (grp) {
 		*tag = xa_pointer_tag(grp);
 		grp = xa_untag_pointer(grp);
@@ -102,24 +102,17 @@ int erofs_register_workgroup(struct super_block *sb,
 		return -EINVAL;
 	}
 
-	err = radix_tree_preload(GFP_NOFS);
-	if (err)
-		return err;
-
 	sbi = EROFS_SB(sb);
-	erofs_workstn_lock(sbi);
-
-	grp = xa_tag_pointer(grp, tag);
 
 	/*
 	 * Bump up reference count before making this workgroup
 	 * visible to other users in order to avoid potential UAF
-	 * without serialized by erofs_workstn_lock.
+	 * without serialized by xa_lock.
 	 */
 	__erofs_workgroup_get(grp);
 
-	err = radix_tree_insert(&sbi->workstn_tree,
-				grp->index, grp);
+	err = xa_insert(&sbi->compression_work, grp->index,
+			xa_tag_pointer(grp, tag), GFP_KERNEL);
 	if (unlikely(err))
 		/*
 		 * it's safe to decrease since the workgroup isn't visible
@@ -127,8 +120,6 @@ int erofs_register_workgroup(struct super_block *sb,
 		 */
 		__erofs_workgroup_put(grp);
 
-	erofs_workstn_unlock(sbi);
-	radix_tree_preload_end();
 	return err;
 }
 
@@ -171,7 +162,7 @@ static bool erofs_try_to_release_workgroup(struct erofs_sb_info *sbi,
 
 	/*
 	 * note that all cached pages should be unlinked
-	 * before delete it from the radix tree.
+	 * before delete it from the xarray.
 	 * Otherwise some cached pages of an orphan old workgroup
 	 * could be still linked after the new one is available.
 	 */
@@ -185,7 +176,7 @@ static bool erofs_try_to_release_workgroup(struct erofs_sb_info *sbi,
 	 * however in order to avoid some race conditions, add a
 	 * DBG_BUGON to observe this in advance.
 	 */
-	DBG_BUGON(xa_untag_pointer(radix_tree_delete(&sbi->workstn_tree,
+	DBG_BUGON(xa_untag_pointer(xa_erase(&sbi->compression_work,
 						     grp->index)) != grp);
 
 	/*
@@ -210,7 +201,7 @@ static bool erofs_try_to_release_workgroup(struct erofs_sb_info *sbi,
 	if (cnt > 1)
 		return false;
 
-	DBG_BUGON(xa_untag_pointer(radix_tree_delete(&sbi->workstn_tree,
+	DBG_BUGON(xa_untag_pointer(xa_erase(&sbi->compression_work,
 						     grp->index)) != grp);
 
 	/* (rarely) could be grabbed again when freeing */
@@ -224,21 +215,12 @@ unsigned long erofs_shrink_workstation(struct erofs_sb_info *sbi,
 				       unsigned long nr_shrink,
 				       bool cleanup)
 {
-	pgoff_t first_index = 0;
-	void *batch[PAGEVEC_SIZE];
+	struct erofs_workgroup *grp;
 	unsigned int freed = 0;
+	unsigned long index;
 
-	int i, found;
-repeat:
-	erofs_workstn_lock(sbi);
-
-	found = radix_tree_gang_lookup(&sbi->workstn_tree,
-				       batch, first_index, PAGEVEC_SIZE);
-
-	for (i = 0; i < found; ++i) {
-		struct erofs_workgroup *grp = xa_untag_pointer(batch[i]);
-
-		first_index = grp->index + 1;
+	xa_for_each(&sbi->compression_work, index, grp) {
+		grp = xa_untag_pointer(grp);
 
 		/* try to shrink each valid workgroup */
 		if (!erofs_try_to_release_workgroup(sbi, grp, cleanup))
@@ -248,10 +230,7 @@ repeat:
 		if (unlikely(!--nr_shrink))
 			break;
 	}
-	erofs_workstn_unlock(sbi);
 
-	if (i && nr_shrink)
-		goto repeat;
 	return freed;
 }