[PATCH 2/4] ovl: use simpler function to convert iocb to rw flags

[Amir Goldstein <amir73il@gmail.com>]

Overlayfs implements its own function to translate iocb flags into rw
flags, so that they can be passed into another vfs call.

With commit ce71bfea207b4 ("fs: align IOCB_* flags with RWF_* flags")
Jens created a 1:1 matching between the iocb flags and rw flags,
simplifying the conversion.

Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/overlayfs/file.c | 34 ++++++++++++++--------------------
 1 file changed, 14 insertions(+), 20 deletions(-)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index c6ad84cf9246..98f0dedffc0f 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -262,20 +262,12 @@ static void ovl_file_accessed(struct file *file)
 	touch_atime(&file->f_path);
 }
 
-static rwf_t ovl_iocb_to_rwf(int ifl)
+#define OVL_IOCB_MASK \
+	(IOCB_NOWAIT | IOCB_HIPRI | IOCB_DSYNC | IOCB_SYNC)
+
+static rwf_t iocb_to_rw_flags(int flags)
 {
-	rwf_t flags = 0;
-
-	if (ifl & IOCB_NOWAIT)
-		flags |= RWF_NOWAIT;
-	if (ifl & IOCB_HIPRI)
-		flags |= RWF_HIPRI;
-	if (ifl & IOCB_DSYNC)
-		flags |= RWF_DSYNC;
-	if (ifl & IOCB_SYNC)
-		flags |= RWF_SYNC;
-
-	return flags;
+	return (__force rwf_t)(flags & OVL_IOCB_MASK);
 }
 
 static inline void ovl_aio_put(struct ovl_aio_req *aio_req)
@@ -333,8 +325,9 @@ static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 
 	old_cred = ovl_override_creds(file_inode(file)->i_sb);
 	if (is_sync_kiocb(iocb)) {
-		ret = vfs_iter_read(real.file, iter, &iocb->ki_pos,
-				    ovl_iocb_to_rwf(iocb->ki_flags));
+		rwf_t rwf = iocb_to_rw_flags(iocb->ki_flags);
+
+		ret = vfs_iter_read(real.file, iter, &iocb->ki_pos, rwf);
 	} else {
 		struct ovl_aio_req *aio_req;
 
@@ -369,7 +362,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 	struct fd real;
 	const struct cred *old_cred;
 	ssize_t ret;
-	int ifl = iocb->ki_flags;
+	int flags = iocb->ki_flags;
 
 	if (!iov_iter_count(iter))
 		return 0;
@@ -391,13 +384,14 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 		goto out_fdput;
 
 	if (!ovl_should_sync(OVL_FS(inode->i_sb)))
-		ifl &= ~(IOCB_DSYNC | IOCB_SYNC);
+		flags &= ~(IOCB_DSYNC | IOCB_SYNC);
 
 	old_cred = ovl_override_creds(file_inode(file)->i_sb);
 	if (is_sync_kiocb(iocb)) {
+		rwf_t rwf = iocb_to_rw_flags(flags);
+
 		file_start_write(real.file);
-		ret = vfs_iter_write(real.file, iter, &iocb->ki_pos,
-				     ovl_iocb_to_rwf(ifl));
+		ret = vfs_iter_write(real.file, iter, &iocb->ki_pos, rwf);
 		file_end_write(real.file);
 		/* Update size */
 		ovl_copyattr(inode);
@@ -412,7 +406,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 		real.flags = 0;
 		aio_req->orig_iocb = iocb;
 		kiocb_clone(&aio_req->iocb, iocb, get_file(real.file));
-		aio_req->iocb.ki_flags = ifl;
+		aio_req->iocb.ki_flags = flags;
 		aio_req->iocb.ki_complete = ovl_aio_rw_complete;
 		refcount_set(&aio_req->ref, 2);
 		kiocb_start_write(&aio_req->iocb);
-- 
2.34.1