iov_iter: Use accessor function

Use accessor functions to access an iterator's type and direction. This
allows for the possibility of using some other method of determining the
type of iterator than if-chains with bitwise-AND conditions.

Signed-off-by: David Howells <[e-mail]>

block/bio.c

···
 	/*
 	 * success
 	 */
-	if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) ||
+	if ((iov_iter_rw(iter) == WRITE && (!map_data || !map_data->null_mapped)) ||
 	    (map_data && map_data->from_user)) {
 		ret = bio_copy_from_iter(bio, iter);
 		if (ret)

fs/block_dev.c

···
 
 	dio->size = 0;
 	dio->multi_bio = false;
-	dio->should_dirty = is_read && (iter->type == ITER_IOVEC);
+	dio->should_dirty = is_read && iter_is_iovec(iter);
 
 	blk_start_plug(&plug);
 	for (;;) {

fs/ceph/file.c

···
 	if (ret < 0)
 		return ret;
 
-	if (unlikely(to->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(to))) {
 		size_t page_off;
 		ret = iov_iter_get_pages_alloc(to, &pages, len,
 					       &page_off);

fs/cifs/file.c

···
 		size_t copy = min_t(size_t, remaining, PAGE_SIZE);
 		size_t written;
 
-		if (unlikely(iter->type & ITER_PIPE)) {
+		if (unlikely(iov_iter_is_pipe(iter))) {
 			void *addr = kmap_atomic(page);
 
 			written = copy_to_iter(addr, copy, iter);
···
 	if (!is_sync_kiocb(iocb))
 		ctx->iocb = iocb;
 
-	if (to->type == ITER_IOVEC)
+	if (iter_is_iovec(to))
 		ctx->should_dirty = true;
 
 	rc = setup_aio_ctx_iter(ctx, to, READ);

fs/cifs/misc.c

···
 	struct page **pages = NULL;
 	struct bio_vec *bv = NULL;
 
-	if (iter->type & ITER_KVEC) {
+	if (iov_iter_is_kvec(iter)) {
 		memcpy(&ctx->iter, iter, sizeof(struct iov_iter));
 		ctx->len = count;
 		iov_iter_advance(iter, count);

fs/cifs/smbdirect.c

···
 
 	info->smbd_recv_pending++;
 
-	switch (msg->msg_iter.type) {
-	case READ | ITER_KVEC:
+	if (iov_iter_rw(&msg->msg_iter) == WRITE) {
+		/* It's a bug in upper layer to get there */
+		cifs_dbg(VFS, "CIFS: invalid msg iter dir %u\n",
+			 iov_iter_rw(&msg->msg_iter));
+		rc = -EINVAL;
+		goto out;
+	}
+
+	switch (iov_iter_type(&msg->msg_iter)) {
+	case ITER_KVEC:
 		buf = msg->msg_iter.kvec->iov_base;
 		to_read = msg->msg_iter.kvec->iov_len;
 		rc = smbd_recv_buf(info, buf, to_read);
 		break;
 
-	case READ | ITER_BVEC:
+	case ITER_BVEC:
 		page = msg->msg_iter.bvec->bv_page;
 		page_offset = msg->msg_iter.bvec->bv_offset;
 		to_read = msg->msg_iter.bvec->bv_len;
···
 	default:
 		/* It's a bug in upper layer to get there */
 		cifs_dbg(VFS, "CIFS: invalid msg type %d\n",
-			msg->msg_iter.type);
+			 iov_iter_type(&msg->msg_iter));
 		rc = -EINVAL;
 	}
 
+out:
 	info->smbd_recv_pending--;
 	wake_up(&info->wait_smbd_recv_pending);
 

fs/direct-io.c

···
 	spin_lock_init(&dio->bio_lock);
 	dio->refcount = 1;
 
-	dio->should_dirty = (iter->type == ITER_IOVEC);
+	dio->should_dirty = iter_is_iovec(iter) && iov_iter_rw(iter) == READ;
 	sdio.iter = iter;
 	sdio.final_block_in_request = end >> blkbits;
 

fs/fuse/file.c

···
 	ssize_t ret = 0;
 
 	/* Special case for kernel I/O: can copy directly into the buffer */
-	if (ii->type & ITER_KVEC) {
+	if (iov_iter_is_kvec(ii)) {
 		unsigned long user_addr = fuse_get_user_addr(ii);
 		size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
 

fs/iomap.c

···
 		if (pos >= dio->i_size)
 			goto out_free_dio;
 
-		if (iter->type == ITER_IOVEC)
+		if (iter_is_iovec(iter) && iov_iter_rw(iter) == READ)
 			dio->flags |= IOMAP_DIO_DIRTY;
 	} else {
 		flags |= IOMAP_WRITE;

include/linux/uio.h

···
 	size_t iov_len;
 };
 
-enum {
+enum iter_type {
 	ITER_IOVEC = 0,
 	ITER_KVEC = 2,
 	ITER_BVEC = 4,
···
 		};
 	};
 };
+
+static inline enum iter_type iov_iter_type(const struct iov_iter *i)
+{
+	return i->type & ~(READ | WRITE);
+}
+
+static inline bool iter_is_iovec(const struct iov_iter *i)
+{
+	return iov_iter_type(i) == ITER_IOVEC;
+}
+
+static inline bool iov_iter_is_kvec(const struct iov_iter *i)
+{
+	return iov_iter_type(i) == ITER_KVEC;
+}
+
+static inline bool iov_iter_is_bvec(const struct iov_iter *i)
+{
+	return iov_iter_type(i) == ITER_BVEC;
+}
+
+static inline bool iov_iter_is_pipe(const struct iov_iter *i)
+{
+	return iov_iter_type(i) == ITER_PIPE;
+}
+
+static inline unsigned char iov_iter_rw(const struct iov_iter *i)
+{
+	return i->type & (READ | WRITE);
+}
 
 /*
  * Total number of bytes covered by an iovec.
···
 }
 
 #define iov_for_each(iov, iter, start)				\
-	if (!((start).type & (ITER_BVEC | ITER_PIPE)))		\
+	if (iov_iter_type(start) == ITER_IOVEC ||		\
+	    iov_iter_type(start) == ITER_KVEC)			\
 	for (iter = (start);					\
 	     (iter).count &&					\
 	     ((iov = iov_iter_iovec(&(iter))), 1);		\
···
 {
 	return i->count;
 }
-
-static inline bool iter_is_iovec(const struct iov_iter *i)
-{
-	return !(i->type & (ITER_BVEC | ITER_KVEC | ITER_PIPE));
-}
-
-/*
- * Get one of READ or WRITE out of iter->type without any other flags OR'd in
- * with it.
- *
- * The ?: is just for type safety.
- */
-#define iov_iter_rw(i) ((0 ? (struct iov_iter *)0 : (i))->type & (READ | WRITE))
 
 /*
  * Cap the iov_iter by given limit; note that the second argument is

lib/iov_iter.c

···
 size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
 {
 	const char *from = addr;
-	if (unlikely(i->type & ITER_PIPE))
+	if (unlikely(iov_iter_is_pipe(i)))
 		return copy_pipe_to_iter(addr, bytes, i);
 	if (iter_is_iovec(i))
 		might_fault();
···
 	const char *from = addr;
 	unsigned long rem, curr_addr, s_addr = (unsigned long) addr;
 
-	if (unlikely(i->type & ITER_PIPE))
+	if (unlikely(iov_iter_is_pipe(i)))
 		return copy_pipe_to_iter_mcsafe(addr, bytes, i);
 	if (iter_is_iovec(i))
 		might_fault();
···
 size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
 {
 	char *to = addr;
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		WARN_ON(1);
 		return 0;
 	}
···
 bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
 {
 	char *to = addr;
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		WARN_ON(1);
 		return false;
 	}
···
 size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
 {
 	char *to = addr;
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		WARN_ON(1);
 		return 0;
 	}
···
 size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
 {
 	char *to = addr;
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		WARN_ON(1);
 		return 0;
 	}
···
 bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
 {
 	char *to = addr;
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		WARN_ON(1);
 		return false;
 	}
···
 		size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
 		kunmap_atomic(kaddr);
 		return wanted;
-	} else if (likely(!(i->type & ITER_PIPE)))
+	} else if (likely(!iov_iter_is_pipe(i)))
 		return copy_page_to_iter_iovec(page, offset, bytes, i);
 	else
 		return copy_page_to_iter_pipe(page, offset, bytes, i);
···
 {
 	if (unlikely(!page_copy_sane(page, offset, bytes)))
 		return 0;
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		WARN_ON(1);
 		return 0;
 	}
···
 
 size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
 {
-	if (unlikely(i->type & ITER_PIPE))
+	if (unlikely(iov_iter_is_pipe(i)))
 		return pipe_zero(bytes, i);
 	iterate_and_advance(i, bytes, v,
 		clear_user(v.iov_base, v.iov_len),
···
 		kunmap_atomic(kaddr);
 		return 0;
 	}
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		kunmap_atomic(kaddr);
 		WARN_ON(1);
 		return 0;
···
 
 void iov_iter_advance(struct iov_iter *i, size_t size)
 {
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		pipe_advance(i, size);
 		return;
 	}
···
 	if (WARN_ON(unroll > MAX_RW_COUNT))
 		return;
 	i->count += unroll;
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		struct pipe_inode_info *pipe = i->pipe;
 		int idx = i->idx;
 		size_t off = i->iov_offset;
···
 		return;
 	}
 	unroll -= i->iov_offset;
-	if (i->type & ITER_BVEC) {
+	if (iov_iter_is_bvec(i)) {
 		const struct bio_vec *bvec = i->bvec;
 		while (1) {
 			size_t n = (--bvec)->bv_len;
···
  */
 size_t iov_iter_single_seg_count(const struct iov_iter *i)
 {
-	if (unlikely(i->type & ITER_PIPE))
+	if (unlikely(iov_iter_is_pipe(i)))
 		return i->count;	// it is a silly place, anyway
 	if (i->nr_segs == 1)
 		return i->count;
-	else if (i->type & ITER_BVEC)
+	else if (iov_iter_is_bvec(i))
 		return min(i->count, i->bvec->bv_len - i->iov_offset);
 	else
 		return min(i->count, i->iov->iov_len - i->iov_offset);
···
 	unsigned long res = 0;
 	size_t size = i->count;
 
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		if (size && i->iov_offset && allocated(&i->pipe->bufs[i->idx]))
 			return size | i->iov_offset;
 		return size;
···
 	unsigned long res = 0;
 	size_t size = i->count;
 
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		WARN_ON(1);
 		return ~0U;
 	}
···
 	if (maxsize > i->count)
 		maxsize = i->count;
 
-	if (unlikely(i->type & ITER_PIPE))
+	if (unlikely(iov_iter_is_pipe(i)))
 		return pipe_get_pages(i, pages, maxsize, maxpages, start);
 	iterate_all_kinds(i, maxsize, v, ({
 		unsigned long addr = (unsigned long)v.iov_base;
···
 			len = maxpages * PAGE_SIZE;
 		addr &= ~(PAGE_SIZE - 1);
 		n = DIV_ROUND_UP(len, PAGE_SIZE);
-		res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
+		res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, pages);
 		if (unlikely(res < 0))
 			return res;
 		return (res == n ? len : res * PAGE_SIZE) - *start;
···
 	if (maxsize > i->count)
 		maxsize = i->count;
 
-	if (unlikely(i->type & ITER_PIPE))
+	if (unlikely(iov_iter_is_pipe(i)))
 		return pipe_get_pages_alloc(i, pages, maxsize, start);
 	iterate_all_kinds(i, maxsize, v, ({
 		unsigned long addr = (unsigned long)v.iov_base;
···
 		p = get_pages_array(n);
 		if (!p)
 			return -ENOMEM;
-		res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
+		res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, p);
 		if (unlikely(res < 0)) {
 			kvfree(p);
 			return res;
···
 	__wsum sum, next;
 	size_t off = 0;
 	sum = *csum;
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		WARN_ON(1);
 		return 0;
 	}
···
 	__wsum sum, next;
 	size_t off = 0;
 	sum = *csum;
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		WARN_ON(1);
 		return false;
 	}
···
 	__wsum sum, next;
 	size_t off = 0;
 	sum = *csum;
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		WARN_ON(1);	/* for now */
 		return 0;
 	}
···
 	if (!size)
 		return 0;
 
-	if (unlikely(i->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(i))) {
 		struct pipe_inode_info *pipe = i->pipe;
 		size_t off;
 		int idx;
···
 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
 {
 	*new = *old;
-	if (unlikely(new->type & ITER_PIPE)) {
+	if (unlikely(iov_iter_is_pipe(new))) {
 		WARN_ON(1);
 		return NULL;
 	}
-	if (new->type & ITER_BVEC)
+	if (iov_iter_is_bvec(new))
 		return new->bvec = kmemdup(new->bvec,
 				    new->nr_segs * sizeof(struct bio_vec),
 				    flags);

mm/filemap.c

···
 					!mapping->a_ops->is_partially_uptodate)
 				goto page_not_up_to_date;
 			/* pipes can't handle partially uptodate pages */
-			if (unlikely(iter->type & ITER_PIPE))
+			if (unlikely(iov_iter_is_pipe(iter)))
 				goto page_not_up_to_date;
 			if (!trylock_page(page))
 				goto page_not_up_to_date;

net/9p/trans_virtio.c

···
 	if (!iov_iter_count(data))
 		return 0;
 
-	if (!(data->type & ITER_KVEC)) {
+	if (iov_iter_is_kvec(data)) {
 		int n;
 		/*
 		 * We allow only p9_max_pages pinned. We wait for the

net/tls/tls_sw.c

···
 	struct crypto_tfm *tfm = crypto_aead_tfm(ctx->aead_send);
 	bool async_capable = tfm->__crt_alg->cra_flags & CRYPTO_ALG_ASYNC;
 	unsigned char record_type = TLS_RECORD_TYPE_DATA;
-	bool is_kvec = msg->msg_iter.type & ITER_KVEC;
+	bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
 	bool eor = !(msg->msg_flags & MSG_MORE);
 	size_t try_to_copy, copied = 0;
 	struct sk_msg *msg_pl, *msg_en;
···
 	bool cmsg = false;
 	int target, err = 0;
 	long timeo;
-	bool is_kvec = msg->msg_iter.type & ITER_KVEC;
+	bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
 	int num_async = 0;
 
 	flags |= nonblock;