On Sat, Feb 11, 2023 at 11:18:38AM +0800, Ming Lei wrote: > 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]. BTW, I meant the added flags are source/sink private flags, which are not used by generic pipe/splice code, just used by the actual source and sink subsystem. thanks, Ming
