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

Pull read/write updates from Al Viro:
 "Christoph's fs/read_write.c series - consolidation and cleanups"

* 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  nfsd: remove nfsd_vfs_read
  nfsd: use vfs_iter_read/write
  fs: implement vfs_iter_write using do_iter_write
  fs: implement vfs_iter_read using do_iter_read
  fs: move more code into do_iter_read/do_iter_write
  fs: remove __do_readv_writev
  fs: remove do_compat_readv_writev
  fs: remove do_readv_writev

drivers/block/loop.c

@@ -273,7 +273,7 @@ static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos)
 	iov_iter_bvec(&i, ITER_BVEC, bvec, 1, bvec->bv_len);
 
 	file_start_write(file);
-	bw = vfs_iter_write(file, &i, ppos);
+	bw = vfs_iter_write(file, &i, ppos, 0);
 	file_end_write(file);
 
 	if (likely(bw ==  bvec->bv_len))
@@ -349,7 +349,7 @@ static int lo_read_simple(struct loop_device *lo, struct request *rq,
 
 	rq_for_each_segment(bvec, rq, iter) {
 		iov_iter_bvec(&i, ITER_BVEC, &bvec, 1, bvec.bv_len);
-		len = vfs_iter_read(lo->lo_backing_file, &i, &pos);
+		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
 		if (len < 0)
 			return len;
 
@@ -390,7 +390,7 @@ static int lo_read_transfer(struct loop_device *lo, struct request *rq,
 		b.bv_len = bvec.bv_len;
 
 		iov_iter_bvec(&i, ITER_BVEC, &b, 1, b.bv_len);
-		len = vfs_iter_read(lo->lo_backing_file, &i, &pos);
+		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
 		if (len < 0) {
 			ret = len;
 			goto out_free_page;

drivers/target/target_core_file.c

@@ -273,9 +273,9 @@ static int fd_do_rw(struct se_cmd *cmd, struct file *fd,
 
 	iov_iter_bvec(&iter, ITER_BVEC, bvec, sgl_nents, len);
 	if (is_write)
-		ret = vfs_iter_write(fd, &iter, &pos);
+		ret = vfs_iter_write(fd, &iter, &pos, 0);
 	else
-		ret = vfs_iter_read(fd, &iter, &pos);
+		ret = vfs_iter_read(fd, &iter, &pos, 0);
 
 	if (is_write) {
 		if (ret < 0 || ret != data_length) {
@@ -409,7 +409,7 @@ fd_execute_write_same(struct se_cmd *cmd)
 	}
 
 	iov_iter_bvec(&iter, ITER_BVEC, bvec, nolb, len);
-	ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos);
+	ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos, 0);
 
 	kfree(bvec);
 	if (ret < 0 || ret != len) {

fs/coda/file.c

@@ -34,7 +34,7 @@ coda_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 
 	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
 
-	return vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos);
+	return vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0);
 }
 
 static ssize_t
@@ -51,7 +51,7 @@ coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to)
 	host_file = cfi->cfi_container;
 	file_start_write(host_file);
 	inode_lock(coda_inode);
-	ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos);
+	ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0);
 	coda_inode->i_size = file_inode(host_file)->i_size;
 	coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
 	coda_inode->i_mtime = coda_inode->i_ctime = current_time(coda_inode);

fs/nfsd/vfs.c

@@ -911,24 +911,13 @@ __be32 nfsd_splice_read(struct svc_rqst *rqstp,
 __be32 nfsd_readv(struct file *file, loff_t offset, struct kvec *vec, int vlen,
 		unsigned long *count)
 {
-	mm_segment_t oldfs;
+	struct iov_iter iter;
 	int host_err;
 
-	oldfs = get_fs();
-	set_fs(KERNEL_DS);
-	host_err = vfs_readv(file, (struct iovec __user *)vec, vlen, &offset, 0);
-	set_fs(oldfs);
-	return nfsd_finish_read(file, count, host_err);
-}
+	iov_iter_kvec(&iter, READ | ITER_KVEC, vec, vlen, *count);
+	host_err = vfs_iter_read(file, &iter, &offset, 0);
 
-static __be32
-nfsd_vfs_read(struct svc_rqst *rqstp, struct file *file,
-	      loff_t offset, struct kvec *vec, int vlen, unsigned long *count)
-{
-	if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
-		return nfsd_splice_read(rqstp, file, offset, count);
-	else
-		return nfsd_readv(file, offset, vec, vlen, count);
+	return nfsd_finish_read(file, count, host_err);
 }
 
 /*
@@ -974,7 +963,7 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 				unsigned long *cnt, int stable)
 {
 	struct svc_export	*exp;
-	mm_segment_t		oldfs;
+	struct iov_iter		iter;
 	__be32			err = 0;
 	int			host_err;
 	int			use_wgather;
@@ -1000,10 +989,8 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct file *file,
 	if (stable && !use_wgather)
 		flags |= RWF_SYNC;
 
-	/* Write the data. */
-	oldfs = get_fs(); set_fs(KERNEL_DS);
-	host_err = vfs_writev(file, (struct iovec __user *)vec, vlen, &pos, flags);
-	set_fs(oldfs);
+	iov_iter_kvec(&iter, WRITE | ITER_KVEC, vec, vlen, *cnt);
+	host_err = vfs_iter_write(file, &iter, &pos, flags);
 	if (host_err < 0)
 		goto out_nfserr;
 	*cnt = host_err;
@@ -1044,7 +1031,12 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	ra = nfsd_init_raparms(file);
 
 	trace_read_opened(rqstp, fhp, offset, vlen);
-	err = nfsd_vfs_read(rqstp, file, offset, vec, vlen, count);
+
+	if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
+		err = nfsd_splice_read(rqstp, file, offset, count);
+	else
+		err = nfsd_readv(file, offset, vec, vlen, count);
+
 	trace_read_io_done(rqstp, fhp, offset, vlen);
 
 	if (ra)

fs/read_write.c

@@ -356,46 +356,6 @@ out_putf:
 }
 #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;
-
-	iter->type |= READ;
-	ret = call_read_iter(file, &kiocb, iter);
-	BUG_ON(ret == -EIOCBQUEUED);
-	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;
-
-	iter->type |= WRITE;
-	ret = call_write_iter(file, &kiocb, iter);
-	BUG_ON(ret == -EIOCBQUEUED);
-	if (ret > 0)
-		*ppos = kiocb.ki_pos;
-	return ret;
-}
-EXPORT_SYMBOL(vfs_iter_write);
-
 int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
 {
 	struct inode *inode;
@@ -910,86 +870,114 @@ out:
 }
 #endif
 
-static ssize_t __do_readv_writev(int type, struct file *file,
-				 struct iov_iter *iter, loff_t *pos, int flags)
+static ssize_t do_iter_read(struct file *file, struct iov_iter *iter,
+		loff_t *pos, int flags)
 {
 	size_t tot_len;
 	ssize_t ret = 0;
 
+	if (!(file->f_mode & FMODE_READ))
+		return -EBADF;
+	if (!(file->f_mode & FMODE_CAN_READ))
+		return -EINVAL;
+
 	tot_len = iov_iter_count(iter);
 	if (!tot_len)
 		goto out;
-	ret = rw_verify_area(type, file, pos, tot_len);
+	ret = rw_verify_area(READ, file, pos, tot_len);
 	if (ret < 0)
-		goto out;
-
-	if (type != READ)
-		file_start_write(file);
+		return ret;
 
-	if ((type == READ && file->f_op->read_iter) ||
-	    (type == WRITE && file->f_op->write_iter))
-		ret = do_iter_readv_writev(file, iter, pos, type, flags);
+	if (file->f_op->read_iter)
+		ret = do_iter_readv_writev(file, iter, pos, READ, flags);
 	else
-		ret = do_loop_readv_writev(file, iter, pos, type, flags);
-
-	if (type != READ)
-		file_end_write(file);
-
+		ret = do_loop_readv_writev(file, iter, pos, READ, flags);
 out:
-	if ((ret + (type == READ)) > 0) {
-		if (type == READ)
-			fsnotify_access(file);
-		else
-			fsnotify_modify(file);
-	}
+	if (ret >= 0)
+		fsnotify_access(file);
 	return ret;
 }
 
-static ssize_t do_readv_writev(int type, struct file *file,
-			       const struct iovec __user *uvector,
-			       unsigned long nr_segs, loff_t *pos,
-			       int flags)
+ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
+		int flags)
 {
-	struct iovec iovstack[UIO_FASTIOV];
-	struct iovec *iov = iovstack;
-	struct iov_iter iter;
-	ssize_t ret;
+	if (!file->f_op->read_iter)
+		return -EINVAL;
+	return do_iter_read(file, iter, ppos, flags);
+}
+EXPORT_SYMBOL(vfs_iter_read);
+
+static ssize_t do_iter_write(struct file *file, struct iov_iter *iter,
+		loff_t *pos, int flags)
+{
+	size_t tot_len;
+	ssize_t ret = 0;
+
+	if (!(file->f_mode & FMODE_WRITE))
+		return -EBADF;
+	if (!(file->f_mode & FMODE_CAN_WRITE))
+		return -EINVAL;
 
-	ret = import_iovec(type, uvector, nr_segs,
-			   ARRAY_SIZE(iovstack), &iov, &iter);
+	tot_len = iov_iter_count(iter);
+	if (!tot_len)
+		return 0;
+	ret = rw_verify_area(WRITE, file, pos, tot_len);
 	if (ret < 0)
 		return ret;
 
-	ret = __do_readv_writev(type, file, &iter, pos, flags);
-	kfree(iov);
-
+	file_start_write(file);
+	if (file->f_op->write_iter)
+		ret = do_iter_readv_writev(file, iter, pos, WRITE, flags);
+	else
+		ret = do_loop_readv_writev(file, iter, pos, WRITE, flags);
+	file_end_write(file);
+	if (ret > 0)
+		fsnotify_modify(file);
 	return ret;
 }
 
+ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
+		int flags)
+{
+	if (!file->f_op->write_iter)
+		return -EINVAL;
+	return do_iter_write(file, iter, ppos, flags);
+}
+EXPORT_SYMBOL(vfs_iter_write);
+
 ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
 		  unsigned long vlen, loff_t *pos, int flags)
 {
-	if (!(file->f_mode & FMODE_READ))
-		return -EBADF;
-	if (!(file->f_mode & FMODE_CAN_READ))
-		return -EINVAL;
+	struct iovec iovstack[UIO_FASTIOV];
+	struct iovec *iov = iovstack;
+	struct iov_iter iter;
+	ssize_t ret;
 
-	return do_readv_writev(READ, file, vec, vlen, pos, flags);
-}
+	ret = import_iovec(READ, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
+	if (ret >= 0) {
+		ret = do_iter_read(file, &iter, pos, flags);
+		kfree(iov);
+	}
 
+	return ret;
+}
 EXPORT_SYMBOL(vfs_readv);
 
 ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
 		   unsigned long vlen, loff_t *pos, int flags)
 {
-	if (!(file->f_mode & FMODE_WRITE))
-		return -EBADF;
-	if (!(file->f_mode & FMODE_CAN_WRITE))
-		return -EINVAL;
+	struct iovec iovstack[UIO_FASTIOV];
+	struct iovec *iov = iovstack;
+	struct iov_iter iter;
+	ssize_t ret;
 
-	return do_readv_writev(WRITE, file, vec, vlen, pos, flags);
+	ret = import_iovec(WRITE, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
+	if (ret >= 0) {
+		ret = do_iter_write(file, &iter, pos, flags);
+		kfree(iov);
+	}
+	return ret;
 }
-
 EXPORT_SYMBOL(vfs_writev);
 
 static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec,
@@ -1137,44 +1125,20 @@ SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec,
 }
 
 #ifdef CONFIG_COMPAT
-
-static ssize_t compat_do_readv_writev(int type, struct file *file,
-			       const struct compat_iovec __user *uvector,
-			       unsigned long nr_segs, loff_t *pos,
-			       int flags)
+static size_t compat_readv(struct file *file,
+			   const struct compat_iovec __user *vec,
+			   unsigned long vlen, loff_t *pos, int flags)
 {
 	struct iovec iovstack[UIO_FASTIOV];
 	struct iovec *iov = iovstack;
 	struct iov_iter iter;
 	ssize_t ret;
 
-	ret = compat_import_iovec(type, uvector, nr_segs,
-				  UIO_FASTIOV, &iov, &iter);
-	if (ret < 0)
-		return ret;
-
-	ret = __do_readv_writev(type, file, &iter, pos, flags);
-	kfree(iov);
-
-	return ret;
-}
-
-static size_t compat_readv(struct file *file,
-			   const struct compat_iovec __user *vec,
-			   unsigned long vlen, loff_t *pos, int flags)
-{
-	ssize_t ret = -EBADF;
-
-	if (!(file->f_mode & FMODE_READ))
-		goto out;
-
-	ret = -EINVAL;
-	if (!(file->f_mode & FMODE_CAN_READ))
-		goto out;
-
-	ret = compat_do_readv_writev(READ, file, vec, vlen, pos, flags);
-
-out:
+	ret = compat_import_iovec(READ, vec, vlen, UIO_FASTIOV, &iov, &iter);
+	if (ret >= 0) {
+		ret = do_iter_read(file, &iter, pos, flags);
+		kfree(iov);
+	}
 	if (ret > 0)
 		add_rchar(current, ret);
 	inc_syscr(current);
@@ -1270,18 +1234,16 @@ static size_t compat_writev(struct file *file,
 			    const struct compat_iovec __user *vec,
 			    unsigned long vlen, loff_t *pos, int flags)
 {
-	ssize_t ret = -EBADF;
-
-	if (!(file->f_mode & FMODE_WRITE))
-		goto out;
-
-	ret = -EINVAL;
-	if (!(file->f_mode & FMODE_CAN_WRITE))
-		goto out;
-
-	ret = compat_do_readv_writev(WRITE, file, vec, vlen, pos, flags);
+	struct iovec iovstack[UIO_FASTIOV];
+	struct iovec *iov = iovstack;
+	struct iov_iter iter;
+	ssize_t ret;
 
-out:
+	ret = compat_import_iovec(WRITE, vec, vlen, UIO_FASTIOV, &iov, &iter);
+	if (ret >= 0) {
+		ret = do_iter_write(file, &iter, pos, flags);
+		kfree(iov);
+	}
 	if (ret > 0)
 		add_wchar(current, ret);
 	inc_syscw(current);

fs/splice.c

@@ -762,7 +762,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 
 		iov_iter_bvec(&from, ITER_BVEC | WRITE, array, n,
 			      sd.total_len - left);
-		ret = vfs_iter_write(out, &from, &sd.pos);
+		ret = vfs_iter_write(out, &from, &sd.pos, 0);
 		if (ret <= 0)
 			break;
 

include/linux/fs.h

@@ -2819,8 +2819,10 @@ extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);
 extern ssize_t generic_file_direct_write(struct kiocb *, struct iov_iter *);
 extern ssize_t generic_perform_write(struct file *, struct iov_iter *, loff_t);
 
-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);
+ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
+		int flags);
+ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
+		int flags);
 
 /* fs/block_dev.c */
 extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);