[PATCH 1/9] fs: refactor new_sync_read

Christoph Hellwig
2020-06-26T07:59:04Z

Pass the read_iter method as a parameter and mark the function
non-static. This allows reusing it for additional callsites e.g.
in procfs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/read_write.c | 8 +++++---
include/linux/fs.h | 2 ++
2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index e7f36b15683049..e765c95ff3440d 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -401,7 +401,8 @@ int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t
read_write == READ ? MAY_READ : MAY_WRITE);
}

-static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
+ssize_t iter_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos,
+ ssize_t (*cb)(struct kiocb *iocb, struct iov_iter *iter))
{
struct iovec iov = { .iov_base = buf, .iov_len = len };
struct kiocb kiocb;
@@ -412,7 +413,7 @@ static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, lo
kiocb.ki_pos = (ppos ? *ppos : 0);
iov_iter_init(&iter, READ, &iov, 1, len);

- ret = call_read_iter(filp, &kiocb, &iter);
+ ret = cb(&kiocb, &iter);
BUG_ON(ret == -EIOCBQUEUED);
if (ppos)
*ppos = kiocb.ki_pos;
@@ -488,7 +489,8 @@ ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
if (file->f_op->read)
ret = file->f_op->read(file, buf, count, pos);
else if (file->f_op->read_iter)
- ret = new_sync_read(file, buf, count, pos);
+ ret = iter_read(file, buf, count, pos,
+ file->f_op->read_iter);
else
ret = -EINVAL;
if (ret > 0) {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index fac6aead402a98..b9b2ee31ef9bf1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1916,6 +1916,8 @@ ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
unsigned long nr_segs, unsigned long fast_segs,
struct iovec *fast_pointer,
struct iovec **ret_pointer);
+ssize_t iter_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos,
+ ssize_t (*cb)(struct kiocb *iocb, struct iov_iter *iter));

extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
--
2.26.2