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erofs: remove void tagging/untagging of workgroup pointers 

Because workgroup pointers inserted to a radix tree are always tagged with
a single value of 0, it is possible to remove tagging and untagging of the
pointers completely.

Signed-off-by: Vladimir Zapolskiy <vladimir@tuxera.com>
Link: https://lore.kernel.org/r/20200102120118.14979-4-vladimir@tuxera.com
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
This commit is contained in:
Vladimir Zapolskiy 2020-01-02 14:01:18 +02:00 committed by Gao Xiang
parent e5e9a43203
commit e3915ad94b
1 changed files with 2 additions and 7 deletions
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9
fs/erofs/utils.c
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@ -68,8 +68,6 @@ repeat:
rcu_read_lock();
grp = radix_tree_lookup(&sbi->workstn_tree, index);
if (grp) {
grp = xa_untag_pointer(grp);
if (erofs_workgroup_get(grp)) {
/* prefer to relax rcu read side */
rcu_read_unlock();
@ -101,8 +99,6 @@ int erofs_register_workgroup(struct super_block *sb,
sbi = EROFS_SB(sb);
xa_lock(&sbi->workstn_tree);
grp = xa_tag_pointer(grp, 0);
/*
* Bump up reference count before making this workgroup
* visible to other users in order to avoid potential UAF
@ -173,8 +169,7 @@ 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,
grp->index)) != grp);
DBG_BUGON(radix_tree_delete(&sbi->workstn_tree, grp->index) != grp);
/*
* If managed cache is on, last refcount should indicate
@ -199,7 +194,7 @@ repeat:
batch, first_index, PAGEVEC_SIZE);
for (i = 0; i < found; ++i) {
struct erofs_workgroup *grp = xa_untag_pointer(batch[i]);
struct erofs_workgroup *grp = batch[i];
first_index = grp->index + 1;