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From:   Alessio Balsini <balsini@android.com>
To:     Miklos Szeredi <miklos@szeredi.hu>
Cc:     Akilesh Kailash <akailash@google.com>,
        Amir Goldstein <amir73il@gmail.com>,
        Antonio SJ Musumeci <trapexit@spawn.link>,
        David Anderson <dvander@google.com>,
        Giuseppe Scrivano <gscrivan@redhat.com>,
        Jann Horn <jannh@google.com>, Jens Axboe <axboe@kernel.dk>,
        Martijn Coenen <maco@android.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Lawrence <paullawrence@google.com>,
        Peng Tao <bergwolf@gmail.com>,
        Stefano Duo <duostefano93@gmail.com>,
        Zimuzo Ezeozue <zezeozue@google.com>, wuyan <wu-yan@tcl.com>,
        fuse-devel@lists.sourceforge.net, kernel-team@android.com,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH RESEND V12 1/8] fs: Generic function to convert iocb to rw flags
Date:   Mon, 25 Jan 2021 15:30:50 +0000
Message-Id: <20210125153057.3623715-2-balsini@android.com>
In-Reply-To: <20210125153057.3623715-1-balsini@android.com>
References: <20210125153057.3623715-1-balsini@android.com>
MIME-Version: 1.0
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Precedence: bulk

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 bd9dd38347ae..56be2ffc5a14 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;
 	struct kiocb *orig_iocb;
@@ -236,22 +238,6 @@ 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 void ovl_aio_cleanup_handler(struct ovl_aio_req *aio_req)
 {
 	struct kiocb *iocb = &aio_req->iocb;
@@ -299,7 +285,8 @@ 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;
 
@@ -356,7 +343,7 @@ 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(ovl_inode_real(inode), inode);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index fd47deea7c17..647c35423545 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3275,6 +3275,11 @@ 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;
-- 
2.30.0.280.ga3ce27912f-goog