[PATCH 05/26] fs: Generic function to convert iocb to rw flags

From: Daniel Rosenberg <drosen@google.com>
To: Miklos Szeredi <miklos@szeredi.hu>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	John Fastabend <john.fastabend@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Daniel Rosenberg <drosen@google.com>,
	Paul Lawrence <paullawrence@google.com>,
	Alessio Balsini <balsini@google.com>,
	David Anderson <dvander@google.com>,
	Sandeep Patil <sspatil@google.com>,
	linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org,
	kernel-team@android.com, Alessio Balsini <balsini@android.com>
Subject: [PATCH 05/26] fs: Generic function to convert iocb to rw flags
Date: Mon, 26 Sep 2022 16:18:01 -0700	[thread overview]
Message-ID: <20220926231822.994383-6-drosen@google.com> (raw)
In-Reply-To: <20220926231822.994383-1-drosen@google.com>

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 daff601b5c41..c9df01577052 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 9eced4cc286e..c1d49675092e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3420,6 +3420,11 @@ 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;
-- 
2.37.3.998.g577e59143f-goog

