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authorAl Viro <viro@zeniv.linux.org.uk>2014-02-12 03:37:41 +0400
committerAl Viro <viro@zeniv.linux.org.uk>2014-05-07 01:36:00 +0400
commit293bc9822fa9b3c9d4b7893bcb241e085580771a (patch)
tree89aae8e9d832199906d413dcffd5b885bcee14fe /Documentation/filesystems
parent7f7f25e82d54870df24d415a7007fbd327da027b (diff)
downloadlinux-293bc9822fa9b3c9d4b7893bcb241e085580771a.tar.xz
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>
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/Locking2
-rw-r--r--Documentation/filesystems/vfs.txt10
2 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 9b0d5a33c8bf..b18dd1779029 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -430,6 +430,8 @@ prototypes:
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);
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 1846374a5add..a1d0d7a30165 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -806,6 +806,8 @@ 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);
@@ -836,11 +838,15 @@ otherwise noted.
read: called by read(2) and related system calls
- aio_read: called by io_submit(2) and other asynchronous I/O operations
+ aio_read: vectored, possibly asynchronous read
+
+ read_iter: possibly asynchronous read with iov_iter as destination
write: called by write(2) and related system calls
- aio_write: called by io_submit(2) and other asynchronous I/O operations
+ aio_write: vectored, possibly asynchronous write
+
+ write_iter: possibly asynchronous write with iov_iter as source
iterate: called when the VFS needs to read the directory contents