On Fri, Feb 10, 2023 at 02:08:35PM -0800, Linus Torvalds wrote: > On Fri, Feb 10, 2023 at 1:51 PM Jens Axboe <axboe@xxxxxxxxx> wrote: > > > > Speaking of splice/io_uring, Ming posted this today: > > > > https://lore.kernel.org/io-uring/20230210153212.733006-1-ming.lei@xxxxxxxxxx/ > > Ugh. Some of that is really ugly. Both 'ignore_sig' and > 'ack_page_consuming' just look wrong. Pure random special cases. > > And that 'ignore_sig' is particularly ugly, since the only thing that > sets it also sets SPLICE_F_NONBLOCK. > > And the *only* thing that actually then checks that field is > 'splice_from_pipe_next()', where there are exactly two > signal_pending() checks that it adds to, and > > (a) the first one is to protect from endless loops > > (b) the second one is irrelevant when SPLICE_F_NONBLOCK is set > > So honestly, just NAK on that series. > > I think that instead of 'ignore_sig' (which shouldn't exist), that > first 'signal_pending()' check in splice_from_pipe_next() should just > be changed into a 'fatal_signal_pending()'. Good point, here the signal is often from task_work_add() called by io_uring. > > But that 'ack_page_consuming' thing looks even more disgusting, and > since I'm not sure why it even exists, I don't know what it's doing > wrong. The motivation is for confirming that if the produced buffer can be used for READ or WRITE. Another way could be to add PIPE_BUF_FLAG_MAY_READ[WRITE]. thanks, Ming
