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 <dhowells@redhat.com>

block/bio.c

@@ -1255,7 +1255,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
 	/*
 	 * 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

@@ -349,7 +349,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages)
 
 	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

@@ -658,7 +658,7 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
 	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

@@ -2990,7 +2990,7 @@ cifs_readdata_to_iov(struct cifs_readdata *rdata, struct iov_iter *iter)
 		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);
@@ -3302,7 +3302,7 @@ ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to)
 	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

@@ -786,7 +786,7 @@ setup_aio_ctx_iter(struct cifs_aio_ctx *ctx, struct iov_iter *iter, int rw)
 	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

@@ -2054,14 +2054,22 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg)
 
 	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;
@@ -2071,10 +2079,11 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg)
 	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

@@ -1313,7 +1313,7 @@ do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
 	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

@@ -1271,7 +1271,7 @@ static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
 	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

@@ -1795,7 +1795,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 		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

@@ -21,7 +21,7 @@ struct kvec {
 	size_t iov_len;
 };
 
-enum {
+enum iter_type {
 	ITER_IOVEC = 0,
 	ITER_KVEC = 2,
 	ITER_BVEC = 4,
@@ -47,6 +47,36 @@ struct iov_iter {
 	};
 };
 
+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.
  *
@@ -74,7 +104,8 @@ static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
 }
 
 #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);		\
@@ -202,19 +233,6 @@ static inline size_t iov_iter_count(const struct iov_iter *i)
 	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
  * *not* the new size - it's upper limit for such.  Passing it a value

lib/iov_iter.c

@@ -558,7 +558,7 @@ static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
 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();
@@ -658,7 +658,7 @@ size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i)
 	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();
@@ -692,7 +692,7 @@ EXPORT_SYMBOL_GPL(_copy_to_iter_mcsafe);
 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;
 	}
@@ -712,7 +712,7 @@ EXPORT_SYMBOL(_copy_from_iter);
 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;
 	}
@@ -739,7 +739,7 @@ EXPORT_SYMBOL(_copy_from_iter_full);
 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;
 	}
@@ -773,7 +773,7 @@ EXPORT_SYMBOL(_copy_from_iter_nocache);
 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;
 	}
@@ -794,7 +794,7 @@ EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache);
 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;
 	}
@@ -836,7 +836,7 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
 		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);
@@ -848,7 +848,7 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
 {
 	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;
 	}
@@ -888,7 +888,7 @@ static size_t pipe_zero(size_t bytes, struct iov_iter *i)
 
 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),
@@ -908,7 +908,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
 		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;
@@ -972,7 +972,7 @@ static void pipe_advance(struct iov_iter *i, size_t size)
 
 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;
 	}
@@ -987,7 +987,7 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll)
 	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;
@@ -1016,7 +1016,7 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll)
 		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;
@@ -1049,11 +1049,11 @@ EXPORT_SYMBOL(iov_iter_revert);
  */
 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);
@@ -1106,7 +1106,7 @@ unsigned long iov_iter_alignment(const struct iov_iter *i)
 	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;
@@ -1125,7 +1125,7 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
 	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;
 	}
@@ -1193,7 +1193,7 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
 	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;
@@ -1205,7 +1205,7 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
 			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;
@@ -1270,7 +1270,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 	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;
@@ -1283,7 +1283,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 		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;
@@ -1313,7 +1313,7 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
 	__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;
 	}
@@ -1355,7 +1355,7 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
 	__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;
 	}
@@ -1400,7 +1400,7 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
 	__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;
 	}
@@ -1443,7 +1443,7 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages)
 	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;
@@ -1481,11 +1481,11 @@ EXPORT_SYMBOL(iov_iter_npages);
 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

@@ -2122,7 +2122,7 @@ static ssize_t generic_file_buffered_read(struct kiocb *iocb,
 					!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

@@ -322,7 +322,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
 	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

@@ -799,7 +799,7 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 	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;
@@ -1457,7 +1457,7 @@ int tls_sw_recvmsg(struct sock *sk,
 	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;