On Wed, 26 May 2010, Changli Gao wrote:
> allow non-block splice only when in file is seekable.
>
> do_splice_to() is split to two parts: read data from in file to spd, and move
> data from spd to pipe. If there isn't much space in pipe for the data in spd,
> and the splice is called with non-block flag, the data dropped due to non
> enough space in pipe will be lost forever when in file isn't seekable.
This is a gratuitous ABI change. I don't think we should hold the
hand of application writers, maybe they _know_ the splice will not
block.
NACK from me.
Miklos
>
> Signed-off-by: Changli Gao <xiaosuo@xxxxxxxxx>
> ----
> fs/splice.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
> diff --git a/fs/splice.c b/fs/splice.c
> index 9e52de5..8137e23 100644
> --- a/fs/splice.c
> +++ b/fs/splice.c
> @@ -1346,8 +1346,12 @@ static long do_splice(struct file *in, loff_t __user *off_in,
> if (copy_from_user(&offset, off_in, sizeof(loff_t)))
> return -EFAULT;
> off = &offset;
> - } else
> + } else {
> + if ((flags & SPLICE_F_NONBLOCK) &&
> + !(in->f_mode & FMODE_PREAD))
> + return -EINVAL;
> off = &in->f_pos;
> + }
>
> ret = do_splice_to(in, off, opipe, len, flags);
>
> --
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