[PATCH 1/8] Use RWF_* flags for AIO operations

[Goldwyn Rodrigues <rgoldwyn-l3A5Bk7waGM@public.gmane.org>]

From: Goldwyn Rodrigues <rgoldwyn-IBi9RG/b67k@public.gmane.org>

RWF_* flags is used for preadv2/pwritev2 calls. Port to use
it for aio operations as well. For this, aio_rw_flags is
introduced in struct iocb (using aio_reserved1) which will
carry these flags.

This is a precursor to the nowait AIO calls.

Note, the only place RWF_HIPRI comes in effect is dio_await_one().
All the rest of the locations, aio code return -EIOCBQUEUED before the
checks for RWF_HIPRI.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn-IBi9RG/b67k@public.gmane.org>
---
 fs/aio.c                     | 10 +++++++++-
 fs/read_write.c              |  7 +------
 include/linux/fs.h           | 12 ++++++++++++
 include/uapi/linux/aio_abi.h |  2 +-
 4 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index f52d925ee259..b8a33f5beef5 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1541,11 +1541,17 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
 	ssize_t ret;
 
 	/* enforce forwards compatibility on users */
-	if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
+	if (unlikely(iocb->aio_reserved2)) {
 		pr_debug("EINVAL: reserve field set\n");
 		return -EINVAL;
 	}
 
+	if (unlikely(iocb->aio_rw_flags & ~(RWF_HIPRI | RWF_DSYNC | RWF_SYNC))) {
+		pr_debug("EINVAL: aio_rw_flags set with incompatible flags\n");
+		return -EINVAL;
+	}
+
+
 	/* prevent overflows */
 	if (unlikely(
 	    (iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
@@ -1586,6 +1592,8 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
 		req->common.ki_flags |= IOCB_EVENTFD;
 	}
 
+	req->common.ki_flags |= iocb_rw_flags(iocb->aio_rw_flags);
+
 	ret = put_user(KIOCB_KEY, &user_iocb->aio_key);
 	if (unlikely(ret)) {
 		pr_debug("EFAULT: aio_key\n");
diff --git a/fs/read_write.c b/fs/read_write.c
index c4f88afbc67f..9aa557bb471c 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -682,12 +682,7 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
 		return -EOPNOTSUPP;
 
 	init_sync_kiocb(&kiocb, filp);
-	if (flags & RWF_HIPRI)
-		kiocb.ki_flags |= IOCB_HIPRI;
-	if (flags & RWF_DSYNC)
-		kiocb.ki_flags |= IOCB_DSYNC;
-	if (flags & RWF_SYNC)
-		kiocb.ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
+	kiocb.ki_flags |= iocb_rw_flags(flags);
 	kiocb.ki_pos = *ppos;
 
 	if (type == READ)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7251f7bb45e8..35cfb08ceb9d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3049,6 +3049,18 @@ static inline int iocb_flags(struct file *file)
 	return res;
 }
 
+static inline int iocb_rw_flags(int flags)
+{
+	int res = 0;
+	if (flags & RWF_HIPRI)
+		res |= IOCB_HIPRI;
+	if (flags & RWF_DSYNC)
+		res |= IOCB_DSYNC;
+	if (flags & RWF_SYNC)
+		res |= (IOCB_DSYNC | IOCB_SYNC);
+	return res;
+}
+
 static inline ino_t parent_ino(struct dentry *dentry)
 {
 	ino_t res;
diff --git a/include/uapi/linux/aio_abi.h b/include/uapi/linux/aio_abi.h
index bb2554f7fbd1..a2d4a8ac94ca 100644
--- a/include/uapi/linux/aio_abi.h
+++ b/include/uapi/linux/aio_abi.h
@@ -79,7 +79,7 @@ struct io_event {
 struct iocb {
 	/* these are internal to the kernel/libc. */
 	__u64	aio_data;	/* data to be returned in event's data */
-	__u32	PADDED(aio_key, aio_reserved1);
+	__u32	PADDED(aio_key, aio_rw_flags);
 				/* the kernel sets aio_key to the req # */
 
 	/* common fields */
-- 
2.12.0