Christoph Hellwig <hch@xxxxxx> writes:
> This adds a flag that tells the file system that this is a high priority
> request for which it's worth to poll the hardware. The flag is purely
> advisory and can be ignored if not supported.
I'm not in love with the HIGHPRI name, but I don't have a better one in
mind. So...
Acked-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/read_write.c | 6 ++++--
> include/linux/fs.h | 1 +
> include/uapi/linux/fs.h | 3 +++
> 3 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/fs/read_write.c b/fs/read_write.c
> index 38b9afa..3b3fb22 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -697,10 +697,12 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
> struct kiocb kiocb;
> ssize_t ret;
>
> - if (flags)
> + if (flags & ~RWF_HIPRI)
> return -EOPNOTSUPP;
>
> init_sync_kiocb(&kiocb, filp);
> + if (flags & RWF_HIPRI)
> + kiocb.ki_flags |= IOCB_HIPRI;
> kiocb.ki_pos = *ppos;
>
> ret = fn(&kiocb, iter);
> @@ -715,7 +717,7 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
> {
> ssize_t ret = 0;
>
> - if (flags)
> + if (flags & ~RWF_HIPRI)
> return -EOPNOTSUPP;
>
> while (iov_iter_count(iter)) {
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 875277a..a1f731c 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -320,6 +320,7 @@ struct writeback_control;
> #define IOCB_EVENTFD (1 << 0)
> #define IOCB_APPEND (1 << 1)
> #define IOCB_DIRECT (1 << 2)
> +#define IOCB_HIPRI (1 << 3)
>
> struct kiocb {
> struct file *ki_filp;
> diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
> index 149bec8..d246339 100644
> --- a/include/uapi/linux/fs.h
> +++ b/include/uapi/linux/fs.h
> @@ -304,4 +304,7 @@ struct fsxattr {
> #define SYNC_FILE_RANGE_WRITE 2
> #define SYNC_FILE_RANGE_WAIT_AFTER 4
>
> +/* flags for preadv2/pwritev2: */
> +#define RWF_HIPRI 0x00000001 /* high priority request, poll if possible */
> +
> #endif /* _UAPI_LINUX_FS_H */
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