On 2/10/23 8:18?PM, 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. Usually you'd use task_sigpending() to distinguis the two, but fatal_signal_pending() as Linus suggests would also work. The only concern here is that since you'll be potentially blocking on waiting for the pipe to be readable - if task does indeed have task_work pending and that very task_work is the one that will ensure that the pipe is now readable, then you're waiting condition will never be satisfied. -- Jens Axboe
