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io_uring: correctly handle non ->{read,write}_iter() file_operations
Currently we just -EINVAL a read or write to an fd that isn't backed by ->read_iter() or ->write_iter(). But we can handle them just fine, as long as we punt fo async context first. Implement a simple loop function for doing ->read() or ->write() instead, and ensure we call it appropriately. Reported-by: 李通洲 <carter.li@eoitek.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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parent
5262f56798
commit
32960613b7
1 changed files with 54 additions and 6 deletions
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@ -1298,6 +1298,51 @@ static void io_async_list_note(int rw, struct io_kiocb *req, size_t len)
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}
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}
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/*
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* For files that don't have ->read_iter() and ->write_iter(), handle them
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* by looping over ->read() or ->write() manually.
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*/
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static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb,
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struct iov_iter *iter)
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{
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ssize_t ret = 0;
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/*
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* Don't support polled IO through this interface, and we can't
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* support non-blocking either. For the latter, this just causes
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* the kiocb to be handled from an async context.
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*/
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if (kiocb->ki_flags & IOCB_HIPRI)
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return -EOPNOTSUPP;
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if (kiocb->ki_flags & IOCB_NOWAIT)
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return -EAGAIN;
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while (iov_iter_count(iter)) {
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struct iovec iovec = iov_iter_iovec(iter);
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ssize_t nr;
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if (rw == READ) {
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nr = file->f_op->read(file, iovec.iov_base,
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iovec.iov_len, &kiocb->ki_pos);
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} else {
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nr = file->f_op->write(file, iovec.iov_base,
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iovec.iov_len, &kiocb->ki_pos);
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}
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if (nr < 0) {
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if (!ret)
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ret = nr;
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break;
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}
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ret += nr;
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if (nr != iovec.iov_len)
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break;
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iov_iter_advance(iter, nr);
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}
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return ret;
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}
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static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
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bool force_nonblock)
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{
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@ -1315,8 +1360,6 @@ static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
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if (unlikely(!(file->f_mode & FMODE_READ)))
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return -EBADF;
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if (unlikely(!file->f_op->read_iter))
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return -EINVAL;
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ret = io_import_iovec(req->ctx, READ, s, &iovec, &iter);
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if (ret < 0)
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@ -1331,7 +1374,11 @@ static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
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if (!ret) {
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ssize_t ret2;
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if (file->f_op->read_iter)
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ret2 = call_read_iter(file, kiocb, &iter);
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else
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ret2 = loop_rw_iter(READ, file, kiocb, &iter);
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/*
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* In case of a short read, punt to async. This can happen
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* if we have data partially cached. Alternatively we can
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@ -1376,8 +1423,6 @@ static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
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file = kiocb->ki_filp;
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if (unlikely(!(file->f_mode & FMODE_WRITE)))
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return -EBADF;
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if (unlikely(!file->f_op->write_iter))
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return -EINVAL;
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ret = io_import_iovec(req->ctx, WRITE, s, &iovec, &iter);
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if (ret < 0)
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@ -1415,7 +1460,10 @@ static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
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}
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kiocb->ki_flags |= IOCB_WRITE;
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if (file->f_op->write_iter)
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ret2 = call_write_iter(file, kiocb, &iter);
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else
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ret2 = loop_rw_iter(WRITE, file, kiocb, &iter);
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if (!force_nonblock || ret2 != -EAGAIN) {
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io_rw_done(kiocb, ret2);
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} else {
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