[RFC PATCH v2 01/21] fs: Generic function to convert iocb to rw flags

Daniel Rosenberg
2022-11-22T02:16:01Z

From: Alessio Balsini <balsini@google.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.

Reduce the OverlayFS code by making the flag conversion function generic
and reusable.

Signed-off-by: Alessio Balsini <balsini@android.com>
---
fs/overlayfs/file.c | 23 +++++------------------
include/linux/fs.h | 5 +++++
2 files changed, 10 insertions(+), 18 deletions(-)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index a1a22f58ba18..287ae968852a 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -15,6 +15,8 @@
#include <linux/fs.h>
#include "overlayfs.h"

+#define OVL_IOCB_MASK (IOCB_DSYNC | IOCB_HIPRI | IOCB_NOWAIT | IOCB_SYNC)
+
struct ovl_aio_req {
struct kiocb iocb;
refcount_t ref;
@@ -240,22 +242,6 @@ static void ovl_file_accessed(struct file *file)
touch_atime(&file->f_path);
}

-static rwf_t ovl_iocb_to_rwf(int ifl)
-{
- 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;
-}
-
static inline void ovl_aio_put(struct ovl_aio_req *aio_req)
{
if (refcount_dec_and_test(&aio_req->ref)) {
@@ -315,7 +301,8 @@ 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));
+ iocb_to_rw_flags(iocb->ki_flags,
+ OVL_IOCB_MASK));
} else {
struct ovl_aio_req *aio_req;

@@ -379,7 +366,7 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
if (is_sync_kiocb(iocb)) {
file_start_write(real.file);
ret = vfs_iter_write(real.file, iter, &iocb->ki_pos,
- ovl_iocb_to_rwf(ifl));
+ iocb_to_rw_flags(ifl, OVL_IOCB_MASK));
file_end_write(real.file);
/* Update size */
ovl_copyattr(inode);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e654435f1651..c913106fdd65 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3434,6 +3434,11 @@ static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags)
return 0;
}

+static inline rwf_t iocb_to_rw_flags(int ifl, int iocb_mask)
+{
+ return ifl & iocb_mask;
+}
+
static inline ino_t parent_ino(struct dentry *dentry)
{
ino_t res;
--
2.38.1.584.g0f3c55d4c2-goog