Attachment #302935 for bug #216458




		if (bufs)	/* More to do? */
			continue;
		if (!pipe->writers)
		{       do_wakeup = 1;
			break;
		}
		if (!pipe->waiting_writers) {
			/* syscall merging: Usually we must not sleep
			 * if O_NONBLOCK is set, or if we got some data.

		}
		if (do_wakeup) {
			wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT | EPOLLWRNORM);
			if ( pipe->fasync_writers )
				kill_fasync(&pipe->fasync_writers, SIGIO, ( ret > 0 ) ? POLL_OUT : ((!pipe->readers) ? POLL_HUP : POLL_OUT));
		}
		pipe_wait(pipe);
	}
	__pipe_unlock(pipe);

	if ( (!pipe->writers) && pipe->fasync_readers )
	       	kill_fasync(&pipe->fasync_readers, SIGIO, POLL_HUP);

	if ( do_wakeup ) {
		/* Signal writers asynchronously that there is more room. */
		wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT | EPOLLWRNORM);
		if ( pipe->fasync_writers )
			kill_fasync(&pipe->fasync_writers, SIGIO, (ret > 0) ? POLL_OUT  : ((!pipe->readers) ? POLL_HUP : POLL_OUT));
	}

	if (ret > 0)
		file_accessed(filp);
	return ret;

		}
		if (do_wakeup) {
			wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN | EPOLLRDNORM);
			if ( pipe->fasync_readers )
				kill_fasync(&pipe->fasync_readers, SIGIO, (ret > 0) ? POLL_IN : ((!pipe->writers) ? POLL_HUP : POLL_IN));
			do_wakeup = 0;
		}
		pipe->waiting_writers++;

	}
out:
	__pipe_unlock(pipe);

	if (do_wakeup) {
		wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN | EPOLLRDNORM);
		if ( pipe->fasync_readers )
			kill_fasync(&pipe->fasync_readers, SIGIO, (ret > 0) ? POLL_IN : ((!pipe->writers) ? POLL_HUP : POLL_IN));
	}

	if ((ret > 0) && sb_start_write_trylock(file_inode(filp)->i_sb)) {
		int err = file_update_time(filp);
		if (err)
			ret = err;


	if (pipe->readers || pipe->writers) {
		wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN | EPOLLOUT | EPOLLRDNORM | EPOLLWRNORM | EPOLLERR | EPOLLHUP);
		if ( pipe->fasync_readers && !pipe->writers )
			kill_fasync(&pipe->fasync_readers, SIGIO, POLL_HUP);
		else if (pipe->fasync_readers)
			kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
		if ( pipe->fasync_writers && !pipe->readers )
			kill_fasync(&pipe->fasync_writers, SIGIO, POLL_HUP);
		else if (pipe->fasync_writers)
			kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
	}

	__pipe_unlock(pipe);

	put_pipe_info(inode, pipe);

Return to bug 216458

Lines 307-313 pipe_read(struct kiocb *iocb, struct iov Link Here

(-)linux-4.18.0-372.26.1.el8.x86_64/fs/pipe.c,kbz216458 (-9 / +28 lines)
307	if (bufs) /* More to do? */	307	if (bufs) /* More to do? */
308	continue;	308	continue;
309	if (!pipe->writers)	309	if (!pipe->writers)
		310	{ do_wakeup = 1;
310	break;	311	break;
		312	}
311	if (!pipe->waiting_writers) {	313	if (!pipe->waiting_writers) {
312	/* syscall merging: Usually we must not sleep	314	/* syscall merging: Usually we must not sleep
313	* if O_NONBLOCK is set, or if we got some data.	315	* if O_NONBLOCK is set, or if we got some data.
Lines 328-344 pipe_read(struct kiocb *iocb, struct iov Link Here
328	}	330	}
329	if (do_wakeup) {	331	if (do_wakeup) {
330	wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT \| EPOLLWRNORM);	332	wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT \| EPOLLWRNORM);
331	kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);	333	if ( pipe->fasync_writers )
		334	kill_fasync(&pipe->fasync_writers, SIGIO, ( ret > 0 ) ? POLL_OUT : ((!pipe->readers) ? POLL_HUP : POLL_OUT));
332	}	335	}
333	pipe_wait(pipe);	336	pipe_wait(pipe);
334	}	337	}
335	__pipe_unlock(pipe);	338	__pipe_unlock(pipe);
336		339
337	/* Signal writers asynchronously that there is more room. */	340	if ( (!pipe->writers) && pipe->fasync_readers )
338	if (do_wakeup) {	341	kill_fasync(&pipe->fasync_readers, SIGIO, POLL_HUP);
		342
		343	if ( do_wakeup ) {
		344	/* Signal writers asynchronously that there is more room. */
339	wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT \| EPOLLWRNORM);	345	wake_up_interruptible_sync_poll(&pipe->wait, EPOLLOUT \| EPOLLWRNORM);
340	kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);	346	if ( pipe->fasync_writers )
		347	kill_fasync(&pipe->fasync_writers, SIGIO, (ret > 0) ? POLL_OUT : ((!pipe->readers) ? POLL_HUP : POLL_OUT));
341	}	348	}
		349
342	if (ret > 0)	350	if (ret > 0)
343	file_accessed(filp);	351	file_accessed(filp);
344	return ret;	352	return ret;
Lines 464-470 pipe_write(struct kiocb *iocb, struct io Link Here
464	}	472	}
465	if (do_wakeup) {	473	if (do_wakeup) {
466	wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN \| EPOLLRDNORM);	474	wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN \| EPOLLRDNORM);
467	kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);	475	if ( pipe->fasync_readers )
		476	kill_fasync(&pipe->fasync_readers, SIGIO, (ret > 0) ? POLL_IN : ((!pipe->writers) ? POLL_HUP : POLL_IN));
468	do_wakeup = 0;	477	do_wakeup = 0;
469	}	478	}
470	pipe->waiting_writers++;	479	pipe->waiting_writers++;
Lines 473-483 pipe_write(struct kiocb *iocb, struct io Link Here
473	}	482	}
474	out:	483	out:
475	__pipe_unlock(pipe);	484	__pipe_unlock(pipe);
		485
476	if (do_wakeup) {	486	if (do_wakeup) {
477	wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN \| EPOLLRDNORM);	487	wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN \| EPOLLRDNORM);
478	kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);	488	if ( pipe->fasync_readers )
		489	kill_fasync(&pipe->fasync_readers, SIGIO, (ret > 0) ? POLL_IN : ((!pipe->writers) ? POLL_HUP : POLL_IN));
479	}	490	}
480	if (ret > 0 && sb_start_write_trylock(file_inode(filp)->i_sb)) {	491
		492	if ((ret > 0) && sb_start_write_trylock(file_inode(filp)->i_sb)) {
481	int err = file_update_time(filp);	493	int err = file_update_time(filp);
482	if (err)	494	if (err)
483	ret = err;	495	ret = err;
Lines 569-577 pipe_release(struct inode *inode, struct Link Here
569		581
570	if (pipe->readers \|\| pipe->writers) {	582	if (pipe->readers \|\| pipe->writers) {
571	wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN \| EPOLLOUT \| EPOLLRDNORM \| EPOLLWRNORM \| EPOLLERR \| EPOLLHUP);	583	wake_up_interruptible_sync_poll(&pipe->wait, EPOLLIN \| EPOLLOUT \| EPOLLRDNORM \| EPOLLWRNORM \| EPOLLERR \| EPOLLHUP);
572	kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);	584	if ( pipe->fasync_readers && !pipe->writers )
573	kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);	585	kill_fasync(&pipe->fasync_readers, SIGIO, POLL_HUP);
		586	else if (pipe->fasync_readers)
		587	kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
		588	if ( pipe->fasync_writers && !pipe->readers )
		589	kill_fasync(&pipe->fasync_writers, SIGIO, POLL_HUP);
		590	else if (pipe->fasync_writers)
		591	kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
574	}	592	}
		593
575	__pipe_unlock(pipe);	594	__pipe_unlock(pipe);
576		595
577	put_pipe_info(inode, pipe);	596	put_pipe_info(inode, pipe);