iov_iter_truncate()

Now It Can Be Done(tm) - we don't need to do iov_shorten() in
generic_file_direct_write() anymore, now that all ->direct_IO()
instances are converted to proper iov_iter methods and honour
iter->count and iter->iov_offset properly.

Get rid of count/ocount arguments of generic_file_direct_write(),
while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 8 insertions, 10 deletions

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 7026014717bc..66d2d5de19d2 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1188,8 +1188,7 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
-	size_t count = 0;
-	size_t ocount = 0;
+	size_t count;
 	ssize_t written = 0;
 	ssize_t written_buffered = 0;
 	struct inode *inode = mapping->host;
@@ -1208,7 +1207,8 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 
 	WARN_ON(iocb->ki_pos != pos);
 
-	count = ocount = iov_length(iov, nr_segs);
+	count = iov_length(iov, nr_segs);
+	iov_iter_init(&i, WRITE, iov, nr_segs, count);
 	mutex_lock(&inode->i_mutex);
 
 	/* We can write back this queue in page reclaim */
@@ -1217,11 +1217,11 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
 	if (err)
 		goto out;
-	iov_iter_init(&i, WRITE, iov, nr_segs, count);
 
 	if (count == 0)
 		goto out;
 
+	iov_iter_truncate(&i, count);
 	err = file_remove_suid(file);
 	if (err)
 		goto out;
@@ -1231,8 +1231,8 @@ static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 		goto out;
 
 	if (file->f_flags & O_DIRECT) {
-		written = generic_file_direct_write(iocb, &i, pos, count, ocount);
-		if (written < 0 || written == count)
+		written = generic_file_direct_write(iocb, &i, pos);
+		if (written < 0 || !iov_iter_count(&i))
 			goto out;
 
 		pos += written;
@@ -1469,8 +1469,7 @@ static ssize_t __fuse_direct_write(struct fuse_io_priv *io,
 
 	res = generic_write_checks(file, ppos, &count, 0);
 	if (!res) {
-		if (iter->count > count)
-			iter->count = count;
+		iov_iter_truncate(iter, count);
 		res = fuse_direct_io(io, iter, ppos, FUSE_DIO_WRITE);
 	}
 
@@ -2896,8 +2895,7 @@ fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
 		if (offset >= i_size)
 			return 0;
 		count = min_t(loff_t, count, fuse_round_up(i_size - offset));
-		if (iter->count > count)
-			iter->count = count;
+		iov_iter_truncate(iter, count);
 	}
 
 	io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);