fs/dcache: Re-use value stored to dentry->d_flags instead of re-reading

Currently, the __d_clear_type_and_inode() writes the value flags to
dentry->d_flags, then immediately re-reads it in order to use it in a if
statement. This re-read is useless because no other update to
dentry->d_flags can occur at this point.

This commit therefore re-use flags in the if statement instead of
re-reading dentry->d_flags.
Signed-off-by: linke li <lilinke99@qq.com>
Link: https://lore.kernel.org/r/tencent_5E187BD0A61BA28605E85405F15228254D0A@qq.comReviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/dcache.c

@@ -355,7 +355,7 @@ static inline void __d_clear_type_and_inode(struct dentry *dentry)
 	flags &= ~DCACHE_ENTRY_TYPE;
 	WRITE_ONCE(dentry->d_flags, flags);
 	dentry->d_inode = NULL;
-	if (dentry->d_flags & DCACHE_LRU_LIST)
+	if (flags & DCACHE_LRU_LIST)
 		this_cpu_inc(nr_dentry_negative);
 }