Commit 5aac0390 authored by Jens Axboe's avatar Jens Axboe Committed by Jakub Kicinski
Browse files

tun: honor IOCB_NOWAIT flag 



tun only checks the file O_NONBLOCK flag, but it should also be checking
the iocb IOCB_NOWAIT flag. Any fops using ->read/write_iter() should check
both, otherwise it breaks users that correctly expect O_NONBLOCK semantics
if IOCB_NOWAIT is set.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/e9451860-96cc-c7c7-47b8-fe42cadd5f4c@kernel.dk


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c5dab094

drivers/net/tun.c

+11 −3
Original line number Diff line number Diff line
@@ -1961,12 +1961,15 @@ static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from) 
	struct tun_file *tfile = file->private_data;

	struct tun_struct *tun = tun_get(tfile);

	ssize_t result;

	int noblock = 0;



	if (!tun)

		return -EBADFD;



	result = tun_get_user(tun, tfile, NULL, from,

			      file->f_flags & O_NONBLOCK, false);

	if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))

		noblock = 1;



	result = tun_get_user(tun, tfile, NULL, from, noblock, false);



	tun_put(tun);

	return result;
@@ -2185,10 +2188,15 @@ static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 
	struct tun_file *tfile = file->private_data;

	struct tun_struct *tun = tun_get(tfile);

	ssize_t len = iov_iter_count(to), ret;

	int noblock = 0;



	if (!tun)

		return -EBADFD;

	ret = tun_do_read(tun, tfile, to, file->f_flags & O_NONBLOCK, NULL);



	if ((file->f_flags & O_NONBLOCK) || (iocb->ki_flags & IOCB_NOWAIT))

		noblock = 1;



	ret = tun_do_read(tun, tfile, to, noblock, NULL);

	ret = min_t(ssize_t, ret, len);

	if (ret > 0)

		iocb->ki_pos = ret;