[PATCH 001/437] fs: split do_loop_readv_writev() into separate read/write side helpers

Jens Axboe
2024-04-11T15:31:31Z

No functional changes, just in preparation for using these separately.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/read_write.c | 43 +++++++++++++++++++++++++++++++++----------
1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index d4c036e82b6c..82ec75937b08 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -746,8 +746,10 @@ 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, int type, rwf_t flags)
+static ssize_t do_loop_readv(struct file *file, struct iov_iter *iter,
+ loff_t *ppos, rwf_t flags,
+ ssize_t (*read)(struct file *, char __user *,
+ size_t, loff_t *))
{
ssize_t ret = 0;

@@ -757,14 +759,35 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
while (iov_iter_count(iter)) {
ssize_t nr;

- if (type == READ) {
- nr = filp->f_op->read(filp, iter_iov_addr(iter),
- iter_iov_len(iter), ppos);
- } else {
- nr = filp->f_op->write(filp, iter_iov_addr(iter),
- iter_iov_len(iter), ppos);
+ nr = read(file, iter_iov_addr(iter), iter_iov_len(iter), ppos);
+ if (nr < 0) {
+ if (!ret)
+ ret = nr;
+ break;
}
+ ret += nr;
+ if (nr != iter_iov_len(iter))
+ break;
+ iov_iter_advance(iter, nr);
+ }
+
+ return ret;
+}
+
+static ssize_t do_loop_writev(struct file *file, struct iov_iter *iter,
+ loff_t *ppos, rwf_t flags,
+ ssize_t (*write)(struct file *, const char __user *,
+ size_t, loff_t *))
+{
+ ssize_t ret = 0;
+
+ if (flags & ~RWF_HIPRI)
+ return -EOPNOTSUPP;
+
+ while (iov_iter_count(iter)) {
+ ssize_t nr;

+ nr = write(file, iter_iov_addr(iter), iter_iov_len(iter), ppos);
if (nr < 0) {
if (!ret)
ret = nr;
@@ -931,7 +954,7 @@ static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
if (file->f_op->read_iter)
ret = do_iter_readv_writev(file, &iter, pos, READ, flags);
else
- ret = do_loop_readv_writev(file, &iter, pos, READ, flags);
+ ret = do_loop_readv(file, &iter, pos, flags, file->f_op->read);
out:
if (ret >= 0)
fsnotify_access(file);
@@ -970,7 +993,7 @@ static ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
if (file->f_op->write_iter)
ret = do_iter_readv_writev(file, &iter, pos, WRITE, flags);
else
- ret = do_loop_readv_writev(file, &iter, pos, WRITE, flags);
+ ret = do_loop_writev(file, &iter, pos, flags, file->f_op->write);
if (ret > 0)
fsnotify_modify(file);
file_end_write(file);
--
2.43.0