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authorJens Axboe <axboe@kernel.dk>2019-09-23 11:05:34 -0600
committerJens Axboe <axboe@kernel.dk>2019-09-23 11:05:34 -0600
commit32960613b7c3352ddf38c42596e28a16ae36335e (patch)
tree60748bfdf64056a50293f2b4c0641c3e728e6813 /fs/io_uring.c
parent5262f567987d3c30052b22e78c35c2313d07b230 (diff)
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>
Diffstat (limited to 'fs/io_uring.c')
-rw-r--r--fs/io_uring.c60
1 files changed, 54 insertions, 6 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 9d8e703bc851..ca7570aca430 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1298,6 +1298,51 @@ static void io_async_list_note(int rw, struct io_kiocb *req, size_t len)
}
}
+/*
+ * For files that don't have ->read_iter() and ->write_iter(), handle them
+ * by looping over ->read() or ->write() manually.
+ */
+static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb,
+ struct iov_iter *iter)
+{
+ ssize_t ret = 0;
+
+ /*
+ * Don't support polled IO through this interface, and we can't
+ * support non-blocking either. For the latter, this just causes
+ * the kiocb to be handled from an async context.
+ */
+ if (kiocb->ki_flags & IOCB_HIPRI)
+ return -EOPNOTSUPP;
+ if (kiocb->ki_flags & IOCB_NOWAIT)
+ return -EAGAIN;
+
+ while (iov_iter_count(iter)) {
+ struct iovec iovec = iov_iter_iovec(iter);
+ ssize_t nr;
+
+ if (rw == READ) {
+ nr = file->f_op->read(file, iovec.iov_base,
+ iovec.iov_len, &kiocb->ki_pos);
+ } else {
+ nr = file->f_op->write(file, iovec.iov_base,
+ iovec.iov_len, &kiocb->ki_pos);
+ }
+
+ if (nr < 0) {
+ if (!ret)
+ ret = nr;
+ break;
+ }
+ ret += nr;
+ if (nr != iovec.iov_len)
+ break;
+ iov_iter_advance(iter, nr);
+ }
+
+ return ret;
+}
+
static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
bool force_nonblock)
{
@@ -1315,8 +1360,6 @@ static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
if (unlikely(!(file->f_mode & FMODE_READ)))
return -EBADF;
- if (unlikely(!file->f_op->read_iter))
- return -EINVAL;
ret = io_import_iovec(req->ctx, READ, s, &iovec, &iter);
if (ret < 0)
@@ -1331,7 +1374,11 @@ static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
if (!ret) {
ssize_t ret2;
- ret2 = call_read_iter(file, kiocb, &iter);
+ if (file->f_op->read_iter)
+ ret2 = call_read_iter(file, kiocb, &iter);
+ else
+ ret2 = loop_rw_iter(READ, file, kiocb, &iter);
+
/*
* In case of a short read, punt to async. This can happen
* if we have data partially cached. Alternatively we can
@@ -1376,8 +1423,6 @@ static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
file = kiocb->ki_filp;
if (unlikely(!(file->f_mode & FMODE_WRITE)))
return -EBADF;
- if (unlikely(!file->f_op->write_iter))
- return -EINVAL;
ret = io_import_iovec(req->ctx, WRITE, s, &iovec, &iter);
if (ret < 0)
@@ -1415,7 +1460,10 @@ static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
}
kiocb->ki_flags |= IOCB_WRITE;
- ret2 = call_write_iter(file, kiocb, &iter);
+ if (file->f_op->write_iter)
+ ret2 = call_write_iter(file, kiocb, &iter);
+ else
+ ret2 = loop_rw_iter(WRITE, file, kiocb, &iter);
if (!force_nonblock || ret2 != -EAGAIN) {
io_rw_done(kiocb, ret2);
} else {