start adding the tag to iov_iter

For now, just use the same thing we pass to ->direct_IO() - it's all
iovec-based at the moment.  Pass it explicitly to iov_iter_init() and
account for kvec vs. iovec in there, by the same kludge NFS ->direct_IO()
uses.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/btrfs/file.c

@@ -1740,7 +1740,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
 		goto out;
 	}
 
-	iov_iter_init(&i, iov, nr_segs, count, 0);
+	iov_iter_init(&i, WRITE, iov, nr_segs, count);
 
 	err = file_remove_suid(file);
 	if (err) {

fs/ceph/file.c

@@ -582,7 +582,7 @@ ceph_sync_direct_write(struct kiocb *iocb, const struct iovec *iov,
 		CEPH_OSD_FLAG_ONDISK |
 		CEPH_OSD_FLAG_WRITE;
 
-	iov_iter_init(&i, iov, nr_segs, count, 0);
+	iov_iter_init(&i, WRITE, iov, nr_segs, count);
 
 	while (iov_iter_count(&i) > 0) {
 		void __user *data = i.iov->iov_base + i.iov_offset;
@@ -703,7 +703,7 @@ static ssize_t ceph_sync_write(struct kiocb *iocb, const struct iovec *iov,
 		CEPH_OSD_FLAG_WRITE |
 		CEPH_OSD_FLAG_ACK;
 
-	iov_iter_init(&i, iov, nr_segs, count, 0);
+	iov_iter_init(&i, WRITE, iov, nr_segs, count);
 
 	while ((len = iov_iter_count(&i)) > 0) {
 		size_t left;
@@ -808,7 +808,7 @@ static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
 	int checkeof = 0, read = 0;
 	struct iov_iter i;
 
-	iov_iter_init(&i, iov, nr_segs, len, 0);
+	iov_iter_init(&i, READ, iov, nr_segs, len);
 
 again:
 	dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
@@ -961,7 +961,7 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
 		 * are pending vmtruncate. So write and vmtruncate
 		 * can not run at the same time
 		 */
-		iov_iter_init(&from, iov, nr_segs, count, 0);
+		iov_iter_init(&from, WRITE, iov, nr_segs, count);
 		written = generic_perform_write(file, &from, pos);
 		if (likely(written >= 0))
 			iocb->ki_pos = pos + written;

fs/cifs/file.c

@@ -2424,7 +2424,7 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
 	else
 		pid = current->tgid;
 
-	iov_iter_init(&it, iov, nr_segs, len, 0);
+	iov_iter_init(&it, WRITE, iov, nr_segs, len);
 	do {
 		size_t save_len;
 
@@ -2854,7 +2854,7 @@ ssize_t cifs_user_readv(struct kiocb *iocb, const struct iovec *iov,
 	if (!len)
 		return 0;
 
-	iov_iter_init(&to, iov, nr_segs, len, 0);
+	iov_iter_init(&to, READ, iov, nr_segs, len);
 
 	INIT_LIST_HEAD(&rdata_list);
 	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);

fs/fuse/file.c

@@ -1217,7 +1217,7 @@ 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, iov, nr_segs, count, 0);
+	iov_iter_init(&i, WRITE, iov, nr_segs, count);
 
 	if (count == 0)
 		goto out;
@@ -1386,7 +1386,7 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
 	struct fuse_req *req;
 	struct iov_iter ii;
 
-	iov_iter_init(&ii, iov, nr_segs, count, 0);
+	iov_iter_init(&ii, write ? WRITE : READ, iov, nr_segs, count);
 
 	if (io->async)
 		req = fuse_get_req_for_background(fc, fuse_iter_npages(&ii));
@@ -2367,7 +2367,7 @@ static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
 	if (!bytes)
 		return 0;
 
-	iov_iter_init(&ii, iov, nr_segs, bytes, 0);
+	iov_iter_init(&ii, to_user ? READ : WRITE, iov, nr_segs, bytes);
 
 	while (iov_iter_count(&ii)) {
 		struct page *page = pages[page_idx++];

fs/nfs/file.c

@@ -173,7 +173,7 @@ nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
 	ssize_t result;
 	struct iov_iter to;
 
-	iov_iter_init(&to, iov, nr_segs, count, 0);
+	iov_iter_init(&to, READ, iov, nr_segs, count);
 
 	if (iocb->ki_filp->f_flags & O_DIRECT)
 		return nfs_file_direct_read(iocb, &to, pos, true);
@@ -648,7 +648,7 @@ ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
 	ssize_t result;
 	size_t count = iov_length(iov, nr_segs);
 	struct iov_iter from;
-	iov_iter_init(&from, iov, nr_segs, count, 0);
+	iov_iter_init(&from, WRITE, iov, nr_segs, count);
 
 	result = nfs_key_timeout_notify(file, inode);
 	if (result)

fs/ocfs2/file.c

@@ -2361,7 +2361,7 @@ static ssize_t ocfs2_file_aio_write(struct kiocb *iocb,
 	if (ret)
 		goto out_dio;
 
-	iov_iter_init(&from, iov, nr_segs, count, 0);
+	iov_iter_init(&from, WRITE, iov, nr_segs, count);
 	if (direct_io) {
 		written = generic_file_direct_write(iocb, &from, *ppos,
 						    count, ocount);

fs/pipe.c

@@ -287,7 +287,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
 	if (unlikely(total_len == 0))
 		return 0;
 
-	iov_iter_init(&iter, iov, nr_segs, total_len, 0);
+	iov_iter_init(&iter, READ, iov, nr_segs, total_len);
 
 	do_wakeup = 0;
 	ret = 0;

fs/splice.c

@@ -1548,7 +1548,7 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov,
 	if (ret <= 0)
 		return ret;
 
-	iov_iter_init(&iter, iov, nr_segs, count, 0);
+	iov_iter_init(&iter, READ, iov, nr_segs, count);
 
 	sd.len = 0;
 	sd.total_len = count;

fs/xfs/xfs_file.c

@@ -697,7 +697,7 @@ xfs_file_dio_aio_write(
 	}
 
 	trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0);
-	iov_iter_init(&from, iovp, nr_segs, count, 0);
+	iov_iter_init(&from, WRITE, iovp, nr_segs, count);
 	ret = generic_file_direct_write(iocb, &from, pos, count, ocount);
 
 out:
@@ -731,7 +731,7 @@ xfs_file_buffered_aio_write(
 	if (ret)
 		goto out;
 
-	iov_iter_init(&from, iovp, nr_segs, count, 0);
+	iov_iter_init(&from, WRITE, iovp, nr_segs, count);
 	/* We can write back this queue in page reclaim */
 	current->backing_dev_info = mapping->backing_dev_info;
 

include/linux/uio.h

@@ -20,6 +20,7 @@ struct kvec {
 };
 
 struct iov_iter {
+	int type;
 	const struct iovec *iov;
 	unsigned long nr_segs;
 	size_t iov_offset;
@@ -68,18 +69,8 @@ size_t iov_iter_single_seg_count(const struct iov_iter *i);
 size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
 			 struct iov_iter *i);
 unsigned long iov_iter_alignment(const struct iov_iter *i);
-
-static inline void iov_iter_init(struct iov_iter *i,
-			const struct iovec *iov, unsigned long nr_segs,
-			size_t count, size_t written)
-{
-	i->iov = iov;
-	i->nr_segs = nr_segs;
-	i->iov_offset = 0;
-	i->count = count + written;
-
-	iov_iter_advance(i, written);
-}
+void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov,
+			unsigned long nr_segs, size_t count);
 
 static inline size_t iov_iter_count(struct iov_iter *i)
 {

mm/filemap.c

@@ -1730,7 +1730,7 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
 	size_t count = iov_length(iov, nr_segs);
 	struct iov_iter i;
 
-	iov_iter_init(&i, iov, nr_segs, count, 0);
+	iov_iter_init(&i, READ, iov, nr_segs, count);
 	return generic_file_read_iter(iocb, &i);
 }
 EXPORT_SYMBOL(generic_file_aio_read);
@@ -2596,7 +2596,7 @@ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 	if (err)
 		goto out;
 
-	iov_iter_init(&from, iov, nr_segs, count, 0);
+	iov_iter_init(&from, WRITE, iov, nr_segs, count);
 
 	/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
 	if (unlikely(file->f_flags & O_DIRECT)) {

mm/iov_iter.c

@@ -220,3 +220,18 @@ unsigned long iov_iter_alignment(const struct iov_iter *i)
 	return res;
 }
 EXPORT_SYMBOL(iov_iter_alignment);
+
+void iov_iter_init(struct iov_iter *i, int direction,
+			const struct iovec *iov, unsigned long nr_segs,
+			size_t count)
+{
+	/* It will get better.  Eventually... */
+	if (segment_eq(get_fs(), KERNEL_DS))
+		direction |= REQ_KERNEL;
+	i->type = direction;
+	i->iov = iov;
+	i->nr_segs = nr_segs;
+	i->iov_offset = 0;
+	i->count = count;
+}
+EXPORT_SYMBOL(iov_iter_init);

mm/page_io.c

@@ -268,7 +268,7 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
 		init_sync_kiocb(&kiocb, swap_file);
 		kiocb.ki_pos = page_file_offset(page);
 		kiocb.ki_nbytes = PAGE_SIZE;
-		iov_iter_init(&from, &iov, 1, PAGE_SIZE, 0);
+		iov_iter_init(&from, KERNEL_WRITE, &iov, 1, PAGE_SIZE);
 
 		set_page_writeback(page);
 		unlock_page(page);

mm/process_vm_access.c

@@ -274,7 +274,7 @@ static ssize_t process_vm_rw(pid_t pid,
 	if (rc <= 0)
 		goto free_iovecs;
 
-	iov_iter_init(&iter, iov_l, liovcnt, rc, 0);
+	iov_iter_init(&iter, vm_write ? WRITE : READ, iov_l, liovcnt, rc);
 
 	rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,
 				   iovstack_r, &iov_r);
@@ -337,7 +337,7 @@ compat_process_vm_rw(compat_pid_t pid,
 						  &iov_l);
 	if (rc <= 0)
 		goto free_iovecs;
-	iov_iter_init(&iter, iov_l, liovcnt, rc, 0);
+	iov_iter_init(&iter, vm_write ? WRITE : READ, iov_l, liovcnt, rc);
 	rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,
 					  UIO_FASTIOV, iovstack_r,
 					  &iov_r);

mm/shmem.c

@@ -1417,7 +1417,7 @@ static ssize_t shmem_file_aio_read(struct kiocb *iocb,
 	loff_t *ppos = &iocb->ki_pos;
 	struct iov_iter iter;
 
-	iov_iter_init(&iter, iov, nr_segs, count, 0);
+	iov_iter_init(&iter, READ, iov, nr_segs, count);
 
 	/*
 	 * Might this read be for a stacking filesystem?  Then when reading