f2fs crypto: use per-inode tfm structure

This patch applies the following ext4 patch:

  ext4 crypto: use per-inode tfm structure

As suggested by Herbert Xu, we shouldn't allocate a new tfm each time
we read or write a page.  Instead we can use a single tfm hanging off
the inode's crypt_info structure for all of our encryption needs for
that inode, since the tfm can be used by multiple crypto requests in
parallel.

Also use cmpxchg() to avoid races that could result in crypt_info
structure getting doubly allocated or doubly freed.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index a316783de8c9..55d0d27dfdf2 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -364,7 +364,7 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
 		if (err)
 			goto err_out;
 
-		err = f2fs_setup_fname_crypto(inode);
+		err = f2fs_get_encryption_info(inode);
 		if (err)
 			goto err_out;
 
@@ -929,7 +929,7 @@ static void *f2fs_encrypted_follow_link(struct dentry *dentry,
 	u32 max_size = inode->i_sb->s_blocksize;
 	int res;
 
-	res = f2fs_setup_fname_crypto(inode);
+	res = f2fs_get_encryption_info(inode);
 	if (res)
 		return ERR_PTR(res);