[PATCH 2/9] vfs: pass type instead of fn to do_{loop,iter}_readv_writev()

Miklos Szeredi
2017-02-17T16:09:48Z

fs/read_write.c | 37 ++++++++++++++++++-------------------
1 file changed, 18 insertions(+), 19 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index b7cf7e2cb8c5..c9da4492a462 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -23,9 +23,6 @@
#include <linux/uaccess.h>
#include <asm/unistd.h>

-typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
-typedef ssize_t (*iter_fn_t)(struct kiocb *, struct iov_iter *);
-
const struct file_operations generic_ro_fops = {
.llseek = generic_file_llseek,
.read_iter = generic_file_read_iter,
@@ -675,7 +672,7 @@ unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
EXPORT_SYMBOL(iov_shorten);

static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
- loff_t *ppos, iter_fn_t fn, int flags)
+ loff_t *ppos, int type, int flags)
{
struct kiocb kiocb;
ssize_t ret;
@@ -692,7 +689,10 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
kiocb.ki_flags |= (IOCB_DSYNC | IOCB_SYNC);
kiocb.ki_pos = *ppos;

- ret = fn(&kiocb, iter);
+ if (type == READ)
+ ret = filp->f_op->read_iter(&kiocb, iter);
+ else
+ ret = filp->f_op->write_iter(&kiocb, iter);
BUG_ON(ret == -EIOCBQUEUED);
*ppos = kiocb.ki_pos;
return ret;
@@ -700,7 +700,7 @@ static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,

/* Do it by hand, with file-ops */
static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
- loff_t *ppos, io_fn_t fn, int flags)
+ loff_t *ppos, int type, int flags)
{
ssize_t ret = 0;

@@ -711,7 +711,13 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
struct iovec iovec = iov_iter_iovec(iter);
ssize_t nr;

- nr = fn(filp, iovec.iov_base, iovec.iov_len, ppos);
+ if (type == READ) {
+ nr = filp->f_op->read(filp, iovec.iov_base,
+ iovec.iov_len, ppos);
+ } else {
+ nr = filp->f_op->write(filp, iovec.iov_base,
+ iovec.iov_len, ppos);
+ }

if (nr < 0) {
if (!ret)
@@ -839,8 +845,6 @@ static ssize_t __do_readv_writev(int type, struct file *file,
{
size_t tot_len;
ssize_t ret = 0;
- io_fn_t fn;
- iter_fn_t iter_fn;

tot_len = iov_iter_count(iter);
if (!tot_len)
@@ -849,19 +853,14 @@ static ssize_t __do_readv_writev(int type, struct file *file,
if (ret < 0)
goto out;

- if (type == READ) {
- fn = file->f_op->read;
- iter_fn = file->f_op->read_iter;
- } else {
- fn = (io_fn_t)file->f_op->write;
- iter_fn = file->f_op->write_iter;
+ if (type != READ)
file_start_write(file);
- }

- if (iter_fn)
- ret = do_iter_readv_writev(file, iter, pos, iter_fn, flags);
+ if ((type == READ && file->f_op->read_iter) ||
+ (type == WRITE && file->f_op->write_iter))
+ ret = do_iter_readv_writev(file, iter, pos, type, flags);
else
- ret = do_loop_readv_writev(file, iter, pos, fn, flags);
+ ret = do_loop_readv_writev(file, iter, pos, type, flags);

if (type != READ)
file_end_write(file);
--
2.5.5