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>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 75eb71357adf..17535e0a4547 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1451,6 +1451,8 @@ struct block_device_operations;
 #define HAVE_COMPAT_IOCTL 1
 #define HAVE_UNLOCKED_IOCTL 1
 
+struct iov_iter;
+
 struct file_operations {
         struct module *owner;
         loff_t (*llseek) (struct file *, loff_t, int);
@@ -1458,6 +1460,8 @@ struct file_operations {
         ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
         ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
         ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
+        ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
+        ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
         int (*iterate) (struct file *, struct dir_context *);
         unsigned int (*poll) (struct file *, struct poll_table_struct *);
         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
@@ -2415,6 +2419,8 @@ extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *, loff
 extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
 extern ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
 extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
+extern ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
+extern ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
 
 /* fs/block_dev.c */
 extern ssize_t blkdev_aio_write(struct kiocb *iocb, const struct iovec *iov,