Merge branch 'iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull iov_iter updates from Al Viro:
 "More iov_iter work - missing counterpart of iov_iter_init() for
  bvec-backed ones and vfs_read_iter()/vfs_write_iter() - wrappers for
  sync calls of ->read_iter()/->write_iter()"

* 'iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: add vfs_iter_{read,write} helpers
  new helper: iov_iter_bvec()

fs/read_write.c

@@ -333,6 +333,52 @@ SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
 }
 #endif
 
+ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos)
+{
+	struct kiocb kiocb;
+	ssize_t ret;
+
+	if (!file->f_op->read_iter)
+		return -EINVAL;
+
+	init_sync_kiocb(&kiocb, file);
+	kiocb.ki_pos = *ppos;
+	kiocb.ki_nbytes = iov_iter_count(iter);
+
+	iter->type |= READ;
+	ret = file->f_op->read_iter(&kiocb, iter);
+	if (ret == -EIOCBQUEUED)
+		ret = wait_on_sync_kiocb(&kiocb);
+
+	if (ret > 0)
+		*ppos = kiocb.ki_pos;
+	return ret;
+}
+EXPORT_SYMBOL(vfs_iter_read);
+
+ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos)
+{
+	struct kiocb kiocb;
+	ssize_t ret;
+
+	if (!file->f_op->write_iter)
+		return -EINVAL;
+
+	init_sync_kiocb(&kiocb, file);
+	kiocb.ki_pos = *ppos;
+	kiocb.ki_nbytes = iov_iter_count(iter);
+
+	iter->type |= WRITE;
+	ret = file->f_op->write_iter(&kiocb, iter);
+	if (ret == -EIOCBQUEUED)
+		ret = wait_on_sync_kiocb(&kiocb);
+
+	if (ret > 0)
+		*ppos = kiocb.ki_pos;
+	return ret;
+}
+EXPORT_SYMBOL(vfs_iter_write);
+
 /*
  * rw_verify_area doesn't like huge counts. We limit
  * them to something that fits in "int" so that others

fs/splice.c

@@ -961,7 +961,6 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 	splice_from_pipe_begin(&sd);
 	while (sd.total_len) {
 		struct iov_iter from;
-		struct kiocb kiocb;
 		size_t left;
 		int n, idx;
 
@@ -1005,29 +1004,15 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 			left -= this_len;
 		}
 
-		/* ... iov_iter */
-		from.type = ITER_BVEC | WRITE;
-		from.bvec = array;
-		from.nr_segs = n;
-		from.count = sd.total_len - left;
-		from.iov_offset = 0;
-
-		/* ... and iocb */
-		init_sync_kiocb(&kiocb, out);
-		kiocb.ki_pos = sd.pos;
-		kiocb.ki_nbytes = sd.total_len - left;
-
-		/* now, send it */
-		ret = out->f_op->write_iter(&kiocb, &from);
-		if (-EIOCBQUEUED == ret)
-			ret = wait_on_sync_kiocb(&kiocb);
-
+		iov_iter_bvec(&from, ITER_BVEC | WRITE, array, n,
+			      sd.total_len - left);
+		ret = vfs_iter_write(out, &from, &sd.pos);
 		if (ret <= 0)
 			break;
 
 		sd.num_spliced += ret;
 		sd.total_len -= ret;
-		*ppos = sd.pos = kiocb.ki_pos;
+		*ppos = sd.pos;
 
 		/* dismiss the fully eaten buffers, adjust the partial one */
 		while (ret) {

include/linux/fs.h

@@ -2548,6 +2548,9 @@ extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t l
 extern ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
 extern ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
 
+ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos);
+ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos);
+
 /* fs/block_dev.c */
 extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);
 extern ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from);

include/linux/uio.h

@@ -88,7 +88,9 @@ size_t iov_iter_zero(size_t bytes, struct iov_iter *);
 unsigned long iov_iter_alignment(const struct iov_iter *i);
 void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
 			unsigned long nr_segs, size_t count);
-void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *iov,
+void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *kvec,
+			unsigned long nr_segs, size_t count);
+void iov_iter_bvec(struct iov_iter *i, int direction, const struct bio_vec *bvec,
 			unsigned long nr_segs, size_t count);
 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
 			size_t maxsize, unsigned maxpages, size_t *start);

mm/iov_iter.c

@@ -501,18 +501,31 @@ size_t iov_iter_single_seg_count(const struct iov_iter *i)
 EXPORT_SYMBOL(iov_iter_single_seg_count);
 
 void iov_iter_kvec(struct iov_iter *i, int direction,
-			const struct kvec *iov, unsigned long nr_segs,
+			const struct kvec *kvec, unsigned long nr_segs,
 			size_t count)
 {
 	BUG_ON(!(direction & ITER_KVEC));
 	i->type = direction;
-	i->kvec = (struct kvec *)iov;
+	i->kvec = kvec;
 	i->nr_segs = nr_segs;
 	i->iov_offset = 0;
 	i->count = count;
 }
 EXPORT_SYMBOL(iov_iter_kvec);
 
+void iov_iter_bvec(struct iov_iter *i, int direction,
+			const struct bio_vec *bvec, unsigned long nr_segs,
+			size_t count)
+{
+	BUG_ON(!(direction & ITER_BVEC));
+	i->type = direction;
+	i->bvec = bvec;
+	i->nr_segs = nr_segs;
+	i->iov_offset = 0;
+	i->count = count;
+}
+EXPORT_SYMBOL(iov_iter_bvec);
+
 unsigned long iov_iter_alignment(const struct iov_iter *i)
 {
 	unsigned long res = 0;

mm/page_io.c

@@ -269,14 +269,9 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
 			.bv_len  = PAGE_SIZE,
 			.bv_offset = 0
 		};
-		struct iov_iter from = {
-			.type = ITER_BVEC | WRITE,
-			.count = PAGE_SIZE,
-			.iov_offset = 0,
-			.nr_segs = 1,
-		};
-		from.bvec = &bv;	/* older gcc versions are broken */
+		struct iov_iter from;
 
+		iov_iter_bvec(&from, ITER_BVEC | WRITE, &bv, 1, PAGE_SIZE);
 		init_sync_kiocb(&kiocb, swap_file);
 		kiocb.ki_pos = page_file_offset(page);
 		kiocb.ki_nbytes = PAGE_SIZE;