diff options
Diffstat (limited to 'fs/io_uring.c')
| -rw-r--r-- | fs/io_uring.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 23e08c10f486..92debd8be535 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1089,7 +1089,7 @@ static int io_read(struct io_kiocb *req, const struct sqe_submit *s, struct iov_iter iter; struct file *file; size_t iov_count; - ssize_t ret; + ssize_t read_size, ret; ret = io_prep_rw(req, s, force_nonblock); if (ret) @@ -1105,13 +1105,24 @@ static int io_read(struct io_kiocb *req, const struct sqe_submit *s, if (ret < 0) return ret; + read_size = ret; iov_count = iov_iter_count(&iter); ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_count); if (!ret) { ssize_t ret2; - /* Catch -EAGAIN return for forced non-blocking submission */ ret2 = call_read_iter(file, kiocb, &iter); + /* + * In case of a short read, punt to async. This can happen + * if we have data partially cached. Alternatively we can + * return the short read, in which case the application will + * need to issue another SQE and wait for it. That SQE will + * need async punt anyway, so it's more efficient to do it + * here. + */ + if (force_nonblock && ret2 > 0 && ret2 < read_size) + ret2 = -EAGAIN; + /* Catch -EAGAIN return for forced non-blocking submission */ if (!force_nonblock || ret2 != -EAGAIN) { io_rw_done(kiocb, ret2); } else { |