On 8/31/20 3:59 AM, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 5.8-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
Here's a backport:
From 0414a859ee85f9a6b7d692fac115594e19f872ee Mon Sep 17 00:00:00 2001
From: Jens Axboe axboe@kernel.dk Date: Wed, 26 Aug 2020 10:36:20 -0600 Subject: [PATCH 3/3] io_uring: make offset == -1 consistent with preadv2/pwritev2
The man page for io_uring generally claims were consistent with what preadv2 and pwritev2 accept, but turns out there's a slight discrepancy in how offset == -1 is handled for pipes/streams. preadv doesn't allow it, but preadv2 does. This currently causes io_uring to return -EINVAL if that is attempted, but we should allow that as documented.
This change makes us consistent with preadv2/pwritev2 for just passing in a NULL ppos for streams if the offset is -1.
Cc: stable@vger.kernel.org # v5.7+ Reported-by: Benedikt Ames wisp3rwind@posteo.eu Signed-off-by: Jens Axboe axboe@kernel.dk --- fs/io_uring.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c index 2b7018456091..4115bfedf15d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2518,6 +2518,11 @@ static ssize_t io_import_iovec(int rw, struct io_kiocb *req, return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter); }
+static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb) +{ + return kiocb->ki_filp->f_mode & FMODE_STREAM ? NULL : &kiocb->ki_pos; +} + /* * For files that don't have ->read_iter() and ->write_iter(), handle them * by looping over ->read() or ->write() manually. @@ -2553,10 +2558,10 @@ static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb,
if (rw == READ) { nr = file->f_op->read(file, iovec.iov_base, - iovec.iov_len, &kiocb->ki_pos); + iovec.iov_len, io_kiocb_ppos(kiocb)); } else { nr = file->f_op->write(file, iovec.iov_base, - iovec.iov_len, &kiocb->ki_pos); + iovec.iov_len, io_kiocb_ppos(kiocb)); }
if (iov_iter_is_bvec(iter)) @@ -2681,7 +2686,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock) goto copy_iov;
iov_count = iov_iter_count(&iter); - ret = rw_verify_area(READ, req->file, &kiocb->ki_pos, iov_count); + ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), iov_count); if (!ret) { ssize_t ret2;
@@ -2780,7 +2785,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock) goto copy_iov;
iov_count = iov_iter_count(&iter); - ret = rw_verify_area(WRITE, req->file, &kiocb->ki_pos, iov_count); + ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), iov_count); if (!ret) { ssize_t ret2;