new methods: ->read_iter() and ->write_iter()
Beginning to introduce those. Just the callers for now, and it's
clumsier than it'll eventually become; once we finish converting
aio_read and aio_write instances, the things will get nicer.
For now, these guys are in parallel to ->aio_read() and ->aio_write();
they take iocb and iov_iter, with everything in iov_iter already
validated. File offset is passed in iocb->ki_pos, iov/nr_segs -
in iov_iter.
Main concerns in that series are stack footprint and ability to
split the damn thing cleanly.
[fix from Peter Ujfalusi <peter.ujfalusi@ti.com> folded]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/aio.c b/fs/aio.c
index a0ed6c7..56b2860 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1241,6 +1241,7 @@
typedef ssize_t (aio_rw_op)(struct kiocb *, const struct iovec *,
unsigned long, loff_t);
+typedef ssize_t (rw_iter_op)(struct kiocb *, struct iov_iter *);
static ssize_t aio_setup_vectored_rw(struct kiocb *kiocb,
int rw, char __user *buf,
@@ -1298,7 +1299,9 @@
int rw;
fmode_t mode;
aio_rw_op *rw_op;
+ rw_iter_op *iter_op;
struct iovec inline_vec, *iovec = &inline_vec;
+ struct iov_iter iter;
switch (opcode) {
case IOCB_CMD_PREAD:
@@ -1306,6 +1309,7 @@
mode = FMODE_READ;
rw = READ;
rw_op = file->f_op->aio_read;
+ iter_op = file->f_op->read_iter;
goto rw_common;
case IOCB_CMD_PWRITE:
@@ -1313,12 +1317,13 @@
mode = FMODE_WRITE;
rw = WRITE;
rw_op = file->f_op->aio_write;
+ iter_op = file->f_op->write_iter;
goto rw_common;
rw_common:
if (unlikely(!(file->f_mode & mode)))
return -EBADF;
- if (!rw_op)
+ if (!rw_op && !iter_op)
return -EINVAL;
ret = (opcode == IOCB_CMD_PREADV ||
@@ -1347,7 +1352,12 @@
if (rw == WRITE)
file_start_write(file);
- ret = rw_op(req, iovec, nr_segs, req->ki_pos);
+ if (iter_op) {
+ iov_iter_init(&iter, rw, iovec, nr_segs, req->ki_nbytes);
+ ret = iter_op(req, &iter);
+ } else {
+ ret = rw_op(req, iovec, nr_segs, req->ki_pos);
+ }
if (rw == WRITE)
file_end_write(file);