Jens Axboe <axboe@xxxxxxxxx> writes:
> From: Christoph Hellwig <hch@xxxxxx>
>
> This new methods is used to explicitly poll for I/O completion for an
> iocb. It must be called for any iocb submitted asynchronously (that
> is with a non-null ki_complete) which has the IOCB_HIPRI flag set.
>
> The method is assisted by a new ki_cookie field in struct iocb to store
> the polling cookie.
>
> TODO: we can probably union ki_cookie with the existing hint and I/O
> priority fields to avoid struct kiocb growth.
Please document return values.
Thanks,
Jeff
>
> Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
> Documentation/filesystems/vfs.txt | 3 +++
> include/linux/fs.h | 2 ++
> 2 files changed, 5 insertions(+)
>
> diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
> index 5f71a252e2e0..d9dc5e4d82b9 100644
> --- a/Documentation/filesystems/vfs.txt
> +++ b/Documentation/filesystems/vfs.txt
> @@ -857,6 +857,7 @@ struct file_operations {
> ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
> ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
> ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
> + int (*iopoll)(struct kiocb *kiocb, bool spin);
> int (*iterate) (struct file *, struct dir_context *);
> int (*iterate_shared) (struct file *, struct dir_context *);
> __poll_t (*poll) (struct file *, struct poll_table_struct *);
> @@ -902,6 +903,8 @@ otherwise noted.
>
> write_iter: possibly asynchronous write with iov_iter as source
>
> + iopoll: called when aio wants to poll for completions on HIPRI iocbs
> +
> iterate: called when the VFS needs to read the directory contents
>
> iterate_shared: called when the VFS needs to read the directory contents
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index a1ab233e6469..6a5f71f8ae06 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -310,6 +310,7 @@ struct kiocb {
> int ki_flags;
> u16 ki_hint;
> u16 ki_ioprio; /* See linux/ioprio.h */
> + unsigned int ki_cookie; /* for ->iopoll */
> } __randomize_layout;
>
> static inline bool is_sync_kiocb(struct kiocb *kiocb)
> @@ -1781,6 +1782,7 @@ struct file_operations {
> ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
> ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
> ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
> + int (*iopoll)(struct kiocb *kiocb, bool spin);
> int (*iterate) (struct file *, struct dir_context *);
> int (*iterate_shared) (struct file *, struct dir_context *);
> __poll_t (*poll) (struct file *, struct poll_table_struct *);
